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495 lines
11 KiB
495 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Generic driver for the OLPC Embedded Controller. |
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* |
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* Author: Andres Salomon <[email protected]> |
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* |
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* Copyright (C) 2011-2012 One Laptop per Child Foundation. |
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*/ |
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#include <linux/completion.h> |
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#include <linux/debugfs.h> |
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#include <linux/spinlock.h> |
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#include <linux/mutex.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include <linux/workqueue.h> |
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#include <linux/init.h> |
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#include <linux/list.h> |
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#include <linux/regulator/driver.h> |
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#include <linux/olpc-ec.h> |
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struct ec_cmd_desc { |
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u8 cmd; |
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u8 *inbuf, *outbuf; |
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size_t inlen, outlen; |
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int err; |
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struct completion finished; |
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struct list_head node; |
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void *priv; |
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}; |
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struct olpc_ec_priv { |
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struct olpc_ec_driver *drv; |
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u8 version; |
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struct work_struct worker; |
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struct mutex cmd_lock; |
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/* DCON regulator */ |
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bool dcon_enabled; |
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/* Pending EC commands */ |
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struct list_head cmd_q; |
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spinlock_t cmd_q_lock; |
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struct dentry *dbgfs_dir; |
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/* |
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* EC event mask to be applied during suspend (defining wakeup |
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* sources). |
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*/ |
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u16 ec_wakeup_mask; |
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/* |
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* Running an EC command while suspending means we don't always finish |
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* the command before the machine suspends. This means that the EC |
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* is expecting the command protocol to finish, but we after a period |
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* of time (while the OS is asleep) the EC times out and restarts its |
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* idle loop. Meanwhile, the OS wakes up, thinks it's still in the |
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* middle of the command protocol, starts throwing random things at |
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* the EC... and everyone's uphappy. |
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*/ |
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bool suspended; |
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}; |
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static struct olpc_ec_driver *ec_driver; |
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static struct olpc_ec_priv *ec_priv; |
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static void *ec_cb_arg; |
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void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg) |
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{ |
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ec_driver = drv; |
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ec_cb_arg = arg; |
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} |
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EXPORT_SYMBOL_GPL(olpc_ec_driver_register); |
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static void olpc_ec_worker(struct work_struct *w) |
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{ |
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struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker); |
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struct ec_cmd_desc *desc = NULL; |
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unsigned long flags; |
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/* Grab the first pending command from the queue */ |
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spin_lock_irqsave(&ec->cmd_q_lock, flags); |
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if (!list_empty(&ec->cmd_q)) { |
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desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node); |
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list_del(&desc->node); |
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} |
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spin_unlock_irqrestore(&ec->cmd_q_lock, flags); |
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/* Do we actually have anything to do? */ |
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if (!desc) |
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return; |
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/* Protect the EC hw with a mutex; only run one cmd at a time */ |
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mutex_lock(&ec->cmd_lock); |
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desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen, |
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desc->outbuf, desc->outlen, ec_cb_arg); |
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mutex_unlock(&ec->cmd_lock); |
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/* Finished, wake up olpc_ec_cmd() */ |
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complete(&desc->finished); |
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/* Run the worker thread again in case there are more cmds pending */ |
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schedule_work(&ec->worker); |
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} |
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/* |
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* Throw a cmd descripter onto the list. We now have SMP OLPC machines, so |
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* locking is pretty critical. |
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*/ |
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static void queue_ec_descriptor(struct ec_cmd_desc *desc, |
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struct olpc_ec_priv *ec) |
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{ |
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unsigned long flags; |
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INIT_LIST_HEAD(&desc->node); |
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spin_lock_irqsave(&ec->cmd_q_lock, flags); |
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list_add_tail(&desc->node, &ec->cmd_q); |
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spin_unlock_irqrestore(&ec->cmd_q_lock, flags); |
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schedule_work(&ec->worker); |
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} |
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int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen) |
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{ |
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struct olpc_ec_priv *ec = ec_priv; |
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struct ec_cmd_desc desc; |
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/* Driver not yet registered. */ |
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if (!ec_driver) |
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return -EPROBE_DEFER; |
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if (WARN_ON(!ec_driver->ec_cmd)) |
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return -ENODEV; |
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if (!ec) |
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return -ENOMEM; |
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/* Suspending in the middle of a command hoses things really badly */ |
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if (WARN_ON(ec->suspended)) |
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return -EBUSY; |
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might_sleep(); |
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desc.cmd = cmd; |
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desc.inbuf = inbuf; |
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desc.outbuf = outbuf; |
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desc.inlen = inlen; |
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desc.outlen = outlen; |
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desc.err = 0; |
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init_completion(&desc.finished); |
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queue_ec_descriptor(&desc, ec); |
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/* Timeouts must be handled in the platform-specific EC hook */ |
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wait_for_completion(&desc.finished); |
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/* The worker thread dequeues the cmd; no need to do anything here */ |
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return desc.err; |
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} |
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EXPORT_SYMBOL_GPL(olpc_ec_cmd); |
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void olpc_ec_wakeup_set(u16 value) |
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{ |
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struct olpc_ec_priv *ec = ec_priv; |
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if (WARN_ON(!ec)) |
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return; |
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ec->ec_wakeup_mask |= value; |
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} |
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EXPORT_SYMBOL_GPL(olpc_ec_wakeup_set); |
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void olpc_ec_wakeup_clear(u16 value) |
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{ |
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struct olpc_ec_priv *ec = ec_priv; |
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if (WARN_ON(!ec)) |
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return; |
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ec->ec_wakeup_mask &= ~value; |
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} |
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EXPORT_SYMBOL_GPL(olpc_ec_wakeup_clear); |
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int olpc_ec_mask_write(u16 bits) |
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{ |
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struct olpc_ec_priv *ec = ec_priv; |
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if (WARN_ON(!ec)) |
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return -ENODEV; |
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/* EC version 0x5f adds support for wide SCI mask */ |
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if (ec->version >= 0x5f) { |
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__be16 ec_word = cpu_to_be16(bits); |
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return olpc_ec_cmd(EC_WRITE_EXT_SCI_MASK, (void *)&ec_word, 2, NULL, 0); |
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} else { |
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u8 ec_byte = bits & 0xff; |
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return olpc_ec_cmd(EC_WRITE_SCI_MASK, &ec_byte, 1, NULL, 0); |
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} |
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} |
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EXPORT_SYMBOL_GPL(olpc_ec_mask_write); |
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/* |
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* Returns true if the compile and runtime configurations allow for EC events |
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* to wake the system. |
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*/ |
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bool olpc_ec_wakeup_available(void) |
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{ |
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if (WARN_ON(!ec_driver)) |
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return false; |
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return ec_driver->wakeup_available; |
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} |
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EXPORT_SYMBOL_GPL(olpc_ec_wakeup_available); |
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int olpc_ec_sci_query(u16 *sci_value) |
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{ |
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struct olpc_ec_priv *ec = ec_priv; |
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int ret; |
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if (WARN_ON(!ec)) |
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return -ENODEV; |
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/* EC version 0x5f adds support for wide SCI mask */ |
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if (ec->version >= 0x5f) { |
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__be16 ec_word; |
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ret = olpc_ec_cmd(EC_EXT_SCI_QUERY, NULL, 0, (void *)&ec_word, 2); |
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if (ret == 0) |
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*sci_value = be16_to_cpu(ec_word); |
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} else { |
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u8 ec_byte; |
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ret = olpc_ec_cmd(EC_SCI_QUERY, NULL, 0, &ec_byte, 1); |
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if (ret == 0) |
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*sci_value = ec_byte; |
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} |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(olpc_ec_sci_query); |
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#ifdef CONFIG_DEBUG_FS |
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/* |
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* debugfs support for "generic commands", to allow sending |
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* arbitrary EC commands from userspace. |
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*/ |
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#define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */ |
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#define EC_MAX_CMD_REPLY (8) |
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static DEFINE_MUTEX(ec_dbgfs_lock); |
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static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY]; |
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static unsigned int ec_dbgfs_resp_bytes; |
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static ssize_t ec_dbgfs_cmd_write(struct file *file, const char __user *buf, |
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size_t size, loff_t *ppos) |
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{ |
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int i, m; |
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unsigned char ec_cmd[EC_MAX_CMD_ARGS]; |
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unsigned int ec_cmd_int[EC_MAX_CMD_ARGS]; |
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char cmdbuf[64]; |
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int ec_cmd_bytes; |
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mutex_lock(&ec_dbgfs_lock); |
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size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size); |
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m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0], |
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&ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2], |
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&ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]); |
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if (m < 2 || ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) { |
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/* reset to prevent overflow on read */ |
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ec_dbgfs_resp_bytes = 0; |
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pr_debug("olpc-ec: bad ec cmd: cmd:response-count [arg1 [arg2 ...]]\n"); |
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size = -EINVAL; |
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goto out; |
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} |
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/* convert scanf'd ints to char */ |
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ec_cmd_bytes = m - 2; |
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for (i = 0; i <= ec_cmd_bytes; i++) |
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ec_cmd[i] = ec_cmd_int[i]; |
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pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %5ph, want %d returns\n", |
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ec_cmd[0], ec_cmd_bytes, ec_cmd + 1, |
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ec_dbgfs_resp_bytes); |
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olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1], |
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ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes); |
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pr_debug("olpc-ec: response %8ph (%d bytes expected)\n", |
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ec_dbgfs_resp, ec_dbgfs_resp_bytes); |
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out: |
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mutex_unlock(&ec_dbgfs_lock); |
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return size; |
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} |
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static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf, |
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size_t size, loff_t *ppos) |
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{ |
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unsigned int i, r; |
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char *rp; |
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char respbuf[64]; |
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mutex_lock(&ec_dbgfs_lock); |
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rp = respbuf; |
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rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]); |
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for (i = 1; i < ec_dbgfs_resp_bytes; i++) |
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rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]); |
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mutex_unlock(&ec_dbgfs_lock); |
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rp += sprintf(rp, "\n"); |
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r = rp - respbuf; |
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return simple_read_from_buffer(buf, size, ppos, respbuf, r); |
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} |
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static const struct file_operations ec_dbgfs_ops = { |
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.write = ec_dbgfs_cmd_write, |
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.read = ec_dbgfs_cmd_read, |
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}; |
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static struct dentry *olpc_ec_setup_debugfs(void) |
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{ |
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struct dentry *dbgfs_dir; |
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dbgfs_dir = debugfs_create_dir("olpc-ec", NULL); |
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if (IS_ERR_OR_NULL(dbgfs_dir)) |
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return NULL; |
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debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops); |
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return dbgfs_dir; |
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} |
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#else |
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static struct dentry *olpc_ec_setup_debugfs(void) |
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{ |
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return NULL; |
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} |
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#endif /* CONFIG_DEBUG_FS */ |
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static int olpc_ec_set_dcon_power(struct olpc_ec_priv *ec, bool state) |
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{ |
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unsigned char ec_byte = state; |
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int ret; |
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if (ec->dcon_enabled == state) |
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return 0; |
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ret = olpc_ec_cmd(EC_DCON_POWER_MODE, &ec_byte, 1, NULL, 0); |
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if (ret) |
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return ret; |
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ec->dcon_enabled = state; |
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return 0; |
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} |
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static int dcon_regulator_enable(struct regulator_dev *rdev) |
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{ |
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struct olpc_ec_priv *ec = rdev_get_drvdata(rdev); |
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return olpc_ec_set_dcon_power(ec, true); |
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} |
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static int dcon_regulator_disable(struct regulator_dev *rdev) |
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{ |
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struct olpc_ec_priv *ec = rdev_get_drvdata(rdev); |
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return olpc_ec_set_dcon_power(ec, false); |
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} |
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static int dcon_regulator_is_enabled(struct regulator_dev *rdev) |
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{ |
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struct olpc_ec_priv *ec = rdev_get_drvdata(rdev); |
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return ec->dcon_enabled ? 1 : 0; |
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} |
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static const struct regulator_ops dcon_regulator_ops = { |
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.enable = dcon_regulator_enable, |
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.disable = dcon_regulator_disable, |
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.is_enabled = dcon_regulator_is_enabled, |
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}; |
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static const struct regulator_desc dcon_desc = { |
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.name = "dcon", |
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.id = 0, |
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.ops = &dcon_regulator_ops, |
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.type = REGULATOR_VOLTAGE, |
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.owner = THIS_MODULE, |
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.enable_time = 25000, |
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}; |
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static int olpc_ec_probe(struct platform_device *pdev) |
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{ |
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struct olpc_ec_priv *ec; |
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struct regulator_config config = { }; |
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struct regulator_dev *regulator; |
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int err; |
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if (!ec_driver) |
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return -ENODEV; |
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ec = kzalloc(sizeof(*ec), GFP_KERNEL); |
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if (!ec) |
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return -ENOMEM; |
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ec->drv = ec_driver; |
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INIT_WORK(&ec->worker, olpc_ec_worker); |
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mutex_init(&ec->cmd_lock); |
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INIT_LIST_HEAD(&ec->cmd_q); |
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spin_lock_init(&ec->cmd_q_lock); |
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ec_priv = ec; |
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platform_set_drvdata(pdev, ec); |
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/* get the EC revision */ |
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err = olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0, &ec->version, 1); |
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if (err) |
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goto error; |
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config.dev = pdev->dev.parent; |
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config.driver_data = ec; |
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ec->dcon_enabled = true; |
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regulator = devm_regulator_register(&pdev->dev, &dcon_desc, &config); |
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if (IS_ERR(regulator)) { |
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dev_err(&pdev->dev, "failed to register DCON regulator\n"); |
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err = PTR_ERR(regulator); |
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goto error; |
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} |
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ec->dbgfs_dir = olpc_ec_setup_debugfs(); |
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return 0; |
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error: |
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ec_priv = NULL; |
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kfree(ec); |
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return err; |
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} |
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static int olpc_ec_suspend(struct device *dev) |
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{ |
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struct platform_device *pdev = to_platform_device(dev); |
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struct olpc_ec_priv *ec = platform_get_drvdata(pdev); |
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int err = 0; |
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olpc_ec_mask_write(ec->ec_wakeup_mask); |
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if (ec_driver->suspend) |
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err = ec_driver->suspend(pdev); |
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if (!err) |
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ec->suspended = true; |
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return err; |
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} |
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static int olpc_ec_resume(struct device *dev) |
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{ |
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struct platform_device *pdev = to_platform_device(dev); |
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struct olpc_ec_priv *ec = platform_get_drvdata(pdev); |
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ec->suspended = false; |
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return ec_driver->resume ? ec_driver->resume(pdev) : 0; |
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} |
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static const struct dev_pm_ops olpc_ec_pm_ops = { |
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.suspend_late = olpc_ec_suspend, |
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.resume_early = olpc_ec_resume, |
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}; |
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static struct platform_driver olpc_ec_plat_driver = { |
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.probe = olpc_ec_probe, |
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.driver = { |
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.name = "olpc-ec", |
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.pm = &olpc_ec_pm_ops, |
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}, |
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}; |
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static int __init olpc_ec_init_module(void) |
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{ |
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return platform_driver_register(&olpc_ec_plat_driver); |
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} |
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arch_initcall(olpc_ec_init_module);
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