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697 lines
19 KiB
697 lines
19 KiB
/* |
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* Bus driver for MIPS Common Device Memory Map (CDMM). |
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* |
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* Copyright (C) 2014-2015 Imagination Technologies Ltd. |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file "COPYING" in the main directory of this archive |
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* for more details. |
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*/ |
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|
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#include <linux/atomic.h> |
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#include <linux/err.h> |
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#include <linux/cpu.h> |
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#include <linux/cpumask.h> |
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#include <linux/io.h> |
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#include <linux/of_address.h> |
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#include <linux/of.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include <linux/smp.h> |
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#include <asm/cdmm.h> |
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#include <asm/hazards.h> |
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#include <asm/mipsregs.h> |
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|
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/* Access control and status register fields */ |
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#define CDMM_ACSR_DEVTYPE_SHIFT 24 |
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#define CDMM_ACSR_DEVTYPE (255ul << CDMM_ACSR_DEVTYPE_SHIFT) |
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#define CDMM_ACSR_DEVSIZE_SHIFT 16 |
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#define CDMM_ACSR_DEVSIZE (31ul << CDMM_ACSR_DEVSIZE_SHIFT) |
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#define CDMM_ACSR_DEVREV_SHIFT 12 |
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#define CDMM_ACSR_DEVREV (15ul << CDMM_ACSR_DEVREV_SHIFT) |
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#define CDMM_ACSR_UW (1ul << 3) |
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#define CDMM_ACSR_UR (1ul << 2) |
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#define CDMM_ACSR_SW (1ul << 1) |
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#define CDMM_ACSR_SR (1ul << 0) |
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|
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/* Each block of device registers is 64 bytes */ |
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#define CDMM_DRB_SIZE 64 |
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#define to_mips_cdmm_driver(d) container_of(d, struct mips_cdmm_driver, drv) |
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/* Default physical base address */ |
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static phys_addr_t mips_cdmm_default_base; |
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/* Bus operations */ |
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static const struct mips_cdmm_device_id * |
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mips_cdmm_lookup(const struct mips_cdmm_device_id *table, |
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struct mips_cdmm_device *dev) |
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{ |
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int ret = 0; |
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for (; table->type; ++table) { |
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ret = (dev->type == table->type); |
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if (ret) |
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break; |
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} |
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return ret ? table : NULL; |
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} |
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static int mips_cdmm_match(struct device *dev, struct device_driver *drv) |
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{ |
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
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struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(drv); |
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return mips_cdmm_lookup(cdrv->id_table, cdev) != NULL; |
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} |
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static int mips_cdmm_uevent(struct device *dev, struct kobj_uevent_env *env) |
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{ |
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
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int retval = 0; |
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retval = add_uevent_var(env, "CDMM_CPU=%u", cdev->cpu); |
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if (retval) |
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return retval; |
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retval = add_uevent_var(env, "CDMM_TYPE=0x%02x", cdev->type); |
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if (retval) |
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return retval; |
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retval = add_uevent_var(env, "CDMM_REV=%u", cdev->rev); |
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if (retval) |
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return retval; |
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retval = add_uevent_var(env, "MODALIAS=mipscdmm:t%02X", cdev->type); |
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return retval; |
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} |
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|
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/* Device attributes */ |
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#define CDMM_ATTR(name, fmt, arg...) \ |
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static ssize_t name##_show(struct device *_dev, \ |
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struct device_attribute *attr, char *buf) \ |
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{ \ |
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struct mips_cdmm_device *dev = to_mips_cdmm_device(_dev); \ |
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return sprintf(buf, fmt, arg); \ |
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} \ |
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static DEVICE_ATTR_RO(name); |
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CDMM_ATTR(cpu, "%u\n", dev->cpu); |
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CDMM_ATTR(type, "0x%02x\n", dev->type); |
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CDMM_ATTR(revision, "%u\n", dev->rev); |
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CDMM_ATTR(modalias, "mipscdmm:t%02X\n", dev->type); |
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CDMM_ATTR(resource, "\t%016llx\t%016llx\t%016lx\n", |
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(unsigned long long)dev->res.start, |
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(unsigned long long)dev->res.end, |
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dev->res.flags); |
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static struct attribute *mips_cdmm_dev_attrs[] = { |
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&dev_attr_cpu.attr, |
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&dev_attr_type.attr, |
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&dev_attr_revision.attr, |
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&dev_attr_modalias.attr, |
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&dev_attr_resource.attr, |
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NULL, |
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}; |
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ATTRIBUTE_GROUPS(mips_cdmm_dev); |
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struct bus_type mips_cdmm_bustype = { |
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.name = "cdmm", |
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.dev_groups = mips_cdmm_dev_groups, |
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.match = mips_cdmm_match, |
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.uevent = mips_cdmm_uevent, |
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}; |
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EXPORT_SYMBOL_GPL(mips_cdmm_bustype); |
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/* |
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* Standard driver callback helpers. |
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* |
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* All the CDMM driver callbacks need to be executed on the appropriate CPU from |
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* workqueues. For the standard driver callbacks we need a work function |
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* (mips_cdmm_{void,int}_work()) to do the actual call from the right CPU, and a |
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* wrapper function (generated with BUILD_PERCPU_HELPER) to arrange for the work |
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* function to be called on that CPU. |
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*/ |
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/** |
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* struct mips_cdmm_work_dev - Data for per-device call work. |
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* @fn: CDMM driver callback function to call for the device. |
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* @dev: CDMM device to pass to @fn. |
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*/ |
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struct mips_cdmm_work_dev { |
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void *fn; |
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struct mips_cdmm_device *dev; |
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}; |
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/** |
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* mips_cdmm_void_work() - Call a void returning CDMM driver callback. |
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* @data: struct mips_cdmm_work_dev pointer. |
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* |
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* A work_on_cpu() callback function to call an arbitrary CDMM driver callback |
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* function which doesn't return a value. |
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*/ |
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static long mips_cdmm_void_work(void *data) |
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{ |
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struct mips_cdmm_work_dev *work = data; |
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void (*fn)(struct mips_cdmm_device *) = work->fn; |
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fn(work->dev); |
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return 0; |
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} |
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/** |
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* mips_cdmm_int_work() - Call an int returning CDMM driver callback. |
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* @data: struct mips_cdmm_work_dev pointer. |
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* |
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* A work_on_cpu() callback function to call an arbitrary CDMM driver callback |
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* function which returns an int. |
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*/ |
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static long mips_cdmm_int_work(void *data) |
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{ |
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struct mips_cdmm_work_dev *work = data; |
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int (*fn)(struct mips_cdmm_device *) = work->fn; |
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return fn(work->dev); |
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} |
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#define _BUILD_RET_void |
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#define _BUILD_RET_int return |
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/** |
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* BUILD_PERCPU_HELPER() - Helper to call a CDMM driver callback on right CPU. |
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* @_ret: Return type (void or int). |
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* @_name: Name of CDMM driver callback function. |
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* |
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* Generates a specific device callback function to call a CDMM driver callback |
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* function on the appropriate CPU for the device, and if applicable return the |
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* result. |
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*/ |
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#define BUILD_PERCPU_HELPER(_ret, _name) \ |
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static _ret mips_cdmm_##_name(struct device *dev) \ |
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{ \ |
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \ |
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struct mips_cdmm_driver *cdrv = to_mips_cdmm_driver(dev->driver); \ |
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struct mips_cdmm_work_dev work = { \ |
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.fn = cdrv->_name, \ |
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.dev = cdev, \ |
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}; \ |
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\ |
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_BUILD_RET_##_ret work_on_cpu(cdev->cpu, \ |
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mips_cdmm_##_ret##_work, &work); \ |
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} |
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/* Driver callback functions */ |
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BUILD_PERCPU_HELPER(int, probe) /* int mips_cdmm_probe(struct device) */ |
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BUILD_PERCPU_HELPER(int, remove) /* int mips_cdmm_remove(struct device) */ |
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BUILD_PERCPU_HELPER(void, shutdown) /* void mips_cdmm_shutdown(struct device) */ |
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/* Driver registration */ |
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/** |
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* mips_cdmm_driver_register() - Register a CDMM driver. |
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* @drv: CDMM driver information. |
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* |
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* Register a CDMM driver with the CDMM subsystem. The driver will be informed |
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* of matching devices which are discovered. |
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* |
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* Returns: 0 on success. |
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*/ |
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int mips_cdmm_driver_register(struct mips_cdmm_driver *drv) |
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{ |
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drv->drv.bus = &mips_cdmm_bustype; |
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if (drv->probe) |
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drv->drv.probe = mips_cdmm_probe; |
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if (drv->remove) |
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drv->drv.remove = mips_cdmm_remove; |
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if (drv->shutdown) |
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drv->drv.shutdown = mips_cdmm_shutdown; |
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return driver_register(&drv->drv); |
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} |
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EXPORT_SYMBOL_GPL(mips_cdmm_driver_register); |
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/** |
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* mips_cdmm_driver_unregister() - Unregister a CDMM driver. |
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* @drv: CDMM driver information. |
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* |
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* Unregister a CDMM driver from the CDMM subsystem. |
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*/ |
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void mips_cdmm_driver_unregister(struct mips_cdmm_driver *drv) |
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{ |
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driver_unregister(&drv->drv); |
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} |
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EXPORT_SYMBOL_GPL(mips_cdmm_driver_unregister); |
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/* CDMM initialisation and bus discovery */ |
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/** |
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* struct mips_cdmm_bus - Info about CDMM bus. |
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* @phys: Physical address at which it is mapped. |
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* @regs: Virtual address where registers can be accessed. |
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* @drbs: Total number of DRBs. |
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* @drbs_reserved: Number of DRBs reserved. |
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* @discovered: Whether the devices on the bus have been discovered yet. |
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* @offline: Whether the CDMM bus is going offline (or very early |
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* coming back online), in which case it should be |
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* reconfigured each time. |
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*/ |
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struct mips_cdmm_bus { |
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phys_addr_t phys; |
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void __iomem *regs; |
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unsigned int drbs; |
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unsigned int drbs_reserved; |
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bool discovered; |
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bool offline; |
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}; |
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static struct mips_cdmm_bus mips_cdmm_boot_bus; |
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static DEFINE_PER_CPU(struct mips_cdmm_bus *, mips_cdmm_buses); |
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static atomic_t mips_cdmm_next_id = ATOMIC_INIT(-1); |
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/** |
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* mips_cdmm_get_bus() - Get the per-CPU CDMM bus information. |
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* |
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* Get information about the per-CPU CDMM bus, if the bus is present. |
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* |
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* The caller must prevent migration to another CPU, either by disabling |
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* pre-emption or by running from a pinned kernel thread. |
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* |
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* Returns: Pointer to CDMM bus information for the current CPU. |
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* May return ERR_PTR(-errno) in case of error, so check with |
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* IS_ERR(). |
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*/ |
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static struct mips_cdmm_bus *mips_cdmm_get_bus(void) |
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{ |
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struct mips_cdmm_bus *bus, **bus_p; |
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unsigned long flags; |
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unsigned int cpu; |
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if (!cpu_has_cdmm) |
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return ERR_PTR(-ENODEV); |
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cpu = smp_processor_id(); |
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/* Avoid early use of per-cpu primitives before initialised */ |
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if (cpu == 0) |
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return &mips_cdmm_boot_bus; |
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/* Get bus pointer */ |
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bus_p = per_cpu_ptr(&mips_cdmm_buses, cpu); |
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local_irq_save(flags); |
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bus = *bus_p; |
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/* Attempt allocation if NULL */ |
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if (unlikely(!bus)) { |
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bus = kzalloc(sizeof(*bus), GFP_ATOMIC); |
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if (unlikely(!bus)) |
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bus = ERR_PTR(-ENOMEM); |
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else |
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*bus_p = bus; |
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} |
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local_irq_restore(flags); |
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return bus; |
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} |
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/** |
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* mips_cdmm_cur_base() - Find current physical base address of CDMM region. |
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* |
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* Returns: Physical base address of CDMM region according to cdmmbase CP0 |
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* register, or 0 if the CDMM region is disabled. |
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*/ |
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static phys_addr_t mips_cdmm_cur_base(void) |
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{ |
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unsigned long cdmmbase = read_c0_cdmmbase(); |
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if (!(cdmmbase & MIPS_CDMMBASE_EN)) |
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return 0; |
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return (cdmmbase >> MIPS_CDMMBASE_ADDR_SHIFT) |
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<< MIPS_CDMMBASE_ADDR_START; |
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} |
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/** |
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* mips_cdmm_phys_base() - Choose a physical base address for CDMM region. |
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* |
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* Picking a suitable physical address at which to map the CDMM region is |
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* platform specific, so this weak function can be overridden by platform |
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* code to pick a suitable value if none is configured by the bootloader. |
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* By default this method tries to find a CDMM-specific node in the system |
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* dtb. Note that this won't work for early serial console. |
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*/ |
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phys_addr_t __weak mips_cdmm_phys_base(void) |
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{ |
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struct device_node *np; |
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struct resource res; |
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int err; |
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np = of_find_compatible_node(NULL, NULL, "mti,mips-cdmm"); |
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if (np) { |
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err = of_address_to_resource(np, 0, &res); |
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if (!err) |
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return res.start; |
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} |
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return 0; |
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} |
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/** |
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* mips_cdmm_setup() - Ensure the CDMM bus is initialised and usable. |
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* @bus: Pointer to bus information for current CPU. |
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* IS_ERR(bus) is checked, so no need for caller to check. |
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* |
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* The caller must prevent migration to another CPU, either by disabling |
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* pre-emption or by running from a pinned kernel thread. |
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* |
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* Returns 0 on success, -errno on failure. |
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*/ |
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static int mips_cdmm_setup(struct mips_cdmm_bus *bus) |
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{ |
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unsigned long cdmmbase, flags; |
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int ret = 0; |
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if (IS_ERR(bus)) |
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return PTR_ERR(bus); |
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local_irq_save(flags); |
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/* Don't set up bus a second time unless marked offline */ |
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if (bus->offline) { |
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/* If CDMM region is still set up, nothing to do */ |
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if (bus->phys == mips_cdmm_cur_base()) |
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goto out; |
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/* |
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* The CDMM region isn't set up as expected, so it needs |
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* reconfiguring, but then we can stop checking it. |
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*/ |
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bus->offline = false; |
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} else if (bus->phys > 1) { |
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goto out; |
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} |
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/* If the CDMM region is already configured, inherit that setup */ |
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if (!bus->phys) |
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bus->phys = mips_cdmm_cur_base(); |
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/* Otherwise, ask platform code for suggestions */ |
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if (!bus->phys) |
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bus->phys = mips_cdmm_phys_base(); |
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/* Otherwise, copy what other CPUs have done */ |
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if (!bus->phys) |
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bus->phys = mips_cdmm_default_base; |
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/* Otherwise, complain once */ |
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if (!bus->phys) { |
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bus->phys = 1; |
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/* |
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* If you hit this, either your bootloader needs to set up the |
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* CDMM on the boot CPU, or else you need to implement |
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* mips_cdmm_phys_base() for your platform (see asm/cdmm.h). |
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*/ |
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pr_err("cdmm%u: Failed to choose a physical base\n", |
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smp_processor_id()); |
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} |
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/* Already complained? */ |
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if (bus->phys == 1) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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/* Record our success for other CPUs to copy */ |
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mips_cdmm_default_base = bus->phys; |
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pr_debug("cdmm%u: Enabling CDMM region at %pa\n", |
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smp_processor_id(), &bus->phys); |
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/* Enable CDMM */ |
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cdmmbase = read_c0_cdmmbase(); |
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cdmmbase &= (1ul << MIPS_CDMMBASE_ADDR_SHIFT) - 1; |
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cdmmbase |= (bus->phys >> MIPS_CDMMBASE_ADDR_START) |
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<< MIPS_CDMMBASE_ADDR_SHIFT; |
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cdmmbase |= MIPS_CDMMBASE_EN; |
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write_c0_cdmmbase(cdmmbase); |
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tlbw_use_hazard(); |
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bus->regs = (void __iomem *)CKSEG1ADDR(bus->phys); |
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bus->drbs = 1 + ((cdmmbase & MIPS_CDMMBASE_SIZE) >> |
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MIPS_CDMMBASE_SIZE_SHIFT); |
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bus->drbs_reserved = !!(cdmmbase & MIPS_CDMMBASE_CI); |
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out: |
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local_irq_restore(flags); |
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return ret; |
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} |
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/** |
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* mips_cdmm_early_probe() - Minimally probe for a specific device on CDMM. |
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* @dev_type: CDMM type code to look for. |
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* |
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* Minimally configure the in-CPU Common Device Memory Map (CDMM) and look for a |
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* specific device. This can be used to find a device very early in boot for |
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* example to configure an early FDC console device. |
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* |
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* The caller must prevent migration to another CPU, either by disabling |
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* pre-emption or by running from a pinned kernel thread. |
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* |
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* Returns: MMIO pointer to device memory. The caller can read the ACSR |
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* register to find more information about the device (such as the |
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* version number or the number of blocks). |
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* May return IOMEM_ERR_PTR(-errno) in case of error, so check with |
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* IS_ERR(). |
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*/ |
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void __iomem *mips_cdmm_early_probe(unsigned int dev_type) |
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{ |
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struct mips_cdmm_bus *bus; |
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void __iomem *cdmm; |
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u32 acsr; |
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unsigned int drb, type, size; |
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int err; |
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if (WARN_ON(!dev_type)) |
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return IOMEM_ERR_PTR(-ENODEV); |
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bus = mips_cdmm_get_bus(); |
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err = mips_cdmm_setup(bus); |
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if (err) |
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return IOMEM_ERR_PTR(err); |
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/* Skip the first block if it's reserved for more registers */ |
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drb = bus->drbs_reserved; |
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cdmm = bus->regs; |
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/* Look for a specific device type */ |
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for (; drb < bus->drbs; drb += size + 1) { |
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acsr = __raw_readl(cdmm + drb * CDMM_DRB_SIZE); |
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type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT; |
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if (type == dev_type) |
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return cdmm + drb * CDMM_DRB_SIZE; |
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size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT; |
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} |
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return IOMEM_ERR_PTR(-ENODEV); |
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} |
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EXPORT_SYMBOL_GPL(mips_cdmm_early_probe); |
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/** |
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* mips_cdmm_release() - Release a removed CDMM device. |
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* @dev: Device object |
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* |
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* Clean up the struct mips_cdmm_device for an unused CDMM device. This is |
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* called automatically by the driver core when a device is removed. |
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*/ |
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static void mips_cdmm_release(struct device *dev) |
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{ |
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struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); |
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kfree(cdev); |
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} |
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/** |
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* mips_cdmm_bus_discover() - Discover the devices on the CDMM bus. |
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* @bus: CDMM bus information, must already be set up. |
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*/ |
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static void mips_cdmm_bus_discover(struct mips_cdmm_bus *bus) |
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{ |
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void __iomem *cdmm; |
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u32 acsr; |
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unsigned int drb, type, size, rev; |
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struct mips_cdmm_device *dev; |
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unsigned int cpu = smp_processor_id(); |
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int ret = 0; |
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int id = 0; |
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/* Skip the first block if it's reserved for more registers */ |
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drb = bus->drbs_reserved; |
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cdmm = bus->regs; |
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/* Discover devices */ |
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bus->discovered = true; |
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pr_info("cdmm%u discovery (%u blocks)\n", cpu, bus->drbs); |
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for (; drb < bus->drbs; drb += size + 1) { |
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acsr = __raw_readl(cdmm + drb * CDMM_DRB_SIZE); |
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type = (acsr & CDMM_ACSR_DEVTYPE) >> CDMM_ACSR_DEVTYPE_SHIFT; |
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size = (acsr & CDMM_ACSR_DEVSIZE) >> CDMM_ACSR_DEVSIZE_SHIFT; |
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rev = (acsr & CDMM_ACSR_DEVREV) >> CDMM_ACSR_DEVREV_SHIFT; |
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|
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if (!type) |
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continue; |
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pr_info("cdmm%u-%u: @%u (%#x..%#x), type 0x%02x, rev %u\n", |
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cpu, id, drb, drb * CDMM_DRB_SIZE, |
|
(drb + size + 1) * CDMM_DRB_SIZE - 1, |
|
type, rev); |
|
|
|
dev = kzalloc(sizeof(*dev), GFP_KERNEL); |
|
if (!dev) |
|
break; |
|
|
|
dev->cpu = cpu; |
|
dev->res.start = bus->phys + drb * CDMM_DRB_SIZE; |
|
dev->res.end = bus->phys + |
|
(drb + size + 1) * CDMM_DRB_SIZE - 1; |
|
dev->res.flags = IORESOURCE_MEM; |
|
dev->type = type; |
|
dev->rev = rev; |
|
dev->dev.parent = get_cpu_device(cpu); |
|
dev->dev.bus = &mips_cdmm_bustype; |
|
dev->dev.id = atomic_inc_return(&mips_cdmm_next_id); |
|
dev->dev.release = mips_cdmm_release; |
|
|
|
dev_set_name(&dev->dev, "cdmm%u-%u", cpu, id); |
|
++id; |
|
ret = device_register(&dev->dev); |
|
if (ret) |
|
put_device(&dev->dev); |
|
} |
|
} |
|
|
|
|
|
/* |
|
* CPU hotplug and initialisation |
|
* |
|
* All the CDMM driver callbacks need to be executed on the appropriate CPU from |
|
* workqueues. For the CPU callbacks, they need to be called for all devices on |
|
* that CPU, so the work function calls bus_for_each_dev, using a helper |
|
* (generated with BUILD_PERDEV_HELPER) to call the driver callback if the |
|
* device's CPU matches. |
|
*/ |
|
|
|
/** |
|
* BUILD_PERDEV_HELPER() - Helper to call a CDMM driver callback if CPU matches. |
|
* @_name: Name of CDMM driver callback function. |
|
* |
|
* Generates a bus_for_each_dev callback function to call a specific CDMM driver |
|
* callback function for the device if the device's CPU matches that pointed to |
|
* by the data argument. |
|
* |
|
* This is used for informing drivers for all devices on a given CPU of some |
|
* event (such as the CPU going online/offline). |
|
* |
|
* It is expected to already be called from the appropriate CPU. |
|
*/ |
|
#define BUILD_PERDEV_HELPER(_name) \ |
|
static int mips_cdmm_##_name##_helper(struct device *dev, void *data) \ |
|
{ \ |
|
struct mips_cdmm_device *cdev = to_mips_cdmm_device(dev); \ |
|
struct mips_cdmm_driver *cdrv; \ |
|
unsigned int cpu = *(unsigned int *)data; \ |
|
\ |
|
if (cdev->cpu != cpu || !dev->driver) \ |
|
return 0; \ |
|
\ |
|
cdrv = to_mips_cdmm_driver(dev->driver); \ |
|
if (!cdrv->_name) \ |
|
return 0; \ |
|
return cdrv->_name(cdev); \ |
|
} |
|
|
|
/* bus_for_each_dev callback helper functions */ |
|
BUILD_PERDEV_HELPER(cpu_down) /* int mips_cdmm_cpu_down_helper(...) */ |
|
BUILD_PERDEV_HELPER(cpu_up) /* int mips_cdmm_cpu_up_helper(...) */ |
|
|
|
/** |
|
* mips_cdmm_cpu_down_prep() - Callback for CPUHP DOWN_PREP: |
|
* Tear down the CDMM bus. |
|
* @cpu: unsigned int CPU number. |
|
* |
|
* This function is executed on the hotplugged CPU and calls the CDMM |
|
* driver cpu_down callback for all devices on that CPU. |
|
*/ |
|
static int mips_cdmm_cpu_down_prep(unsigned int cpu) |
|
{ |
|
struct mips_cdmm_bus *bus; |
|
long ret; |
|
|
|
/* Inform all the devices on the bus */ |
|
ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, &cpu, |
|
mips_cdmm_cpu_down_helper); |
|
|
|
/* |
|
* While bus is offline, each use of it should reconfigure it just in |
|
* case it is first use when coming back online again. |
|
*/ |
|
bus = mips_cdmm_get_bus(); |
|
if (!IS_ERR(bus)) |
|
bus->offline = true; |
|
|
|
return ret; |
|
} |
|
|
|
/** |
|
* mips_cdmm_cpu_online() - Callback for CPUHP ONLINE: Bring up the CDMM bus. |
|
* @cpu: unsigned int CPU number. |
|
* |
|
* This work_on_cpu callback function is executed on a given CPU to discover |
|
* CDMM devices on that CPU, or to call the CDMM driver cpu_up callback for all |
|
* devices already discovered on that CPU. |
|
* |
|
* It is used as work_on_cpu callback function during |
|
* initialisation. When CPUs are brought online the function is |
|
* invoked directly on the hotplugged CPU. |
|
*/ |
|
static int mips_cdmm_cpu_online(unsigned int cpu) |
|
{ |
|
struct mips_cdmm_bus *bus; |
|
long ret; |
|
|
|
bus = mips_cdmm_get_bus(); |
|
ret = mips_cdmm_setup(bus); |
|
if (ret) |
|
return ret; |
|
|
|
/* Bus now set up, so we can drop the offline flag if still set */ |
|
bus->offline = false; |
|
|
|
if (!bus->discovered) |
|
mips_cdmm_bus_discover(bus); |
|
else |
|
/* Inform all the devices on the bus */ |
|
ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, &cpu, |
|
mips_cdmm_cpu_up_helper); |
|
|
|
return ret; |
|
} |
|
|
|
/** |
|
* mips_cdmm_init() - Initialise CDMM bus. |
|
* |
|
* Initialise CDMM bus, discover CDMM devices for online CPUs, and arrange for |
|
* hotplug notifications so the CDMM drivers can be kept up to date. |
|
*/ |
|
static int __init mips_cdmm_init(void) |
|
{ |
|
int ret; |
|
|
|
/* Register the bus */ |
|
ret = bus_register(&mips_cdmm_bustype); |
|
if (ret) |
|
return ret; |
|
|
|
/* We want to be notified about new CPUs */ |
|
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "bus/cdmm:online", |
|
mips_cdmm_cpu_online, mips_cdmm_cpu_down_prep); |
|
if (ret < 0) |
|
pr_warn("cdmm: Failed to register CPU notifier\n"); |
|
|
|
return ret; |
|
} |
|
subsys_initcall(mips_cdmm_init);
|
|
|