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421 lines
9.2 KiB
421 lines
9.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2020 BAIKAL ELECTRONICS, JSC |
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* |
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* Authors: |
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* Serge Semin <[email protected]> |
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* |
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* Baikal-T1 APB-bus driver |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/types.h> |
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#include <linux/device.h> |
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#include <linux/atomic.h> |
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#include <linux/platform_device.h> |
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#include <linux/interrupt.h> |
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#include <linux/io.h> |
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#include <linux/nmi.h> |
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#include <linux/of.h> |
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#include <linux/regmap.h> |
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#include <linux/clk.h> |
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#include <linux/reset.h> |
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#include <linux/time64.h> |
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#include <linux/clk.h> |
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#include <linux/sysfs.h> |
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#define APB_EHB_ISR 0x00 |
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#define APB_EHB_ISR_PENDING BIT(0) |
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#define APB_EHB_ISR_MASK BIT(1) |
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#define APB_EHB_ADDR 0x04 |
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#define APB_EHB_TIMEOUT 0x08 |
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#define APB_EHB_TIMEOUT_MIN 0x000003FFU |
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#define APB_EHB_TIMEOUT_MAX 0xFFFFFFFFU |
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/* |
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* struct bt1_apb - Baikal-T1 APB EHB private data |
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* @dev: Pointer to the device structure. |
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* @regs: APB EHB registers map. |
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* @res: No-device error injection memory region. |
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* @irq: Errors IRQ number. |
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* @rate: APB-bus reference clock rate. |
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* @pclk: APB-reference clock. |
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* @prst: APB domain reset line. |
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* @count: Number of errors detected. |
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*/ |
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struct bt1_apb { |
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struct device *dev; |
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struct regmap *regs; |
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void __iomem *res; |
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int irq; |
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unsigned long rate; |
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struct clk *pclk; |
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struct reset_control *prst; |
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atomic_t count; |
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}; |
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static const struct regmap_config bt1_apb_regmap_cfg = { |
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.reg_bits = 32, |
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.val_bits = 32, |
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.reg_stride = 4, |
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.max_register = APB_EHB_TIMEOUT, |
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.fast_io = true |
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}; |
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static inline unsigned long bt1_apb_n_to_timeout_us(struct bt1_apb *apb, u32 n) |
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{ |
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u64 timeout = (u64)n * USEC_PER_SEC; |
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do_div(timeout, apb->rate); |
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return timeout; |
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} |
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static inline unsigned long bt1_apb_timeout_to_n_us(struct bt1_apb *apb, |
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unsigned long timeout) |
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{ |
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u64 n = (u64)timeout * apb->rate; |
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do_div(n, USEC_PER_SEC); |
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return n; |
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} |
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static irqreturn_t bt1_apb_isr(int irq, void *data) |
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{ |
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struct bt1_apb *apb = data; |
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u32 addr = 0; |
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regmap_read(apb->regs, APB_EHB_ADDR, &addr); |
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dev_crit_ratelimited(apb->dev, |
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"APB-bus fault %d: Slave access timeout at 0x%08x\n", |
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atomic_inc_return(&apb->count), |
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addr); |
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/* |
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* Print backtrace on each CPU. This might be pointless if the fault |
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* has happened on the same CPU as the IRQ handler is executed or |
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* the other core proceeded further execution despite the error. |
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* But if it's not, by looking at the trace we would get straight to |
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* the cause of the problem. |
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*/ |
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trigger_all_cpu_backtrace(); |
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regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING, 0); |
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return IRQ_HANDLED; |
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} |
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static void bt1_apb_clear_data(void *data) |
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{ |
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struct bt1_apb *apb = data; |
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struct platform_device *pdev = to_platform_device(apb->dev); |
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platform_set_drvdata(pdev, NULL); |
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} |
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static struct bt1_apb *bt1_apb_create_data(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct bt1_apb *apb; |
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int ret; |
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apb = devm_kzalloc(dev, sizeof(*apb), GFP_KERNEL); |
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if (!apb) |
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return ERR_PTR(-ENOMEM); |
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ret = devm_add_action(dev, bt1_apb_clear_data, apb); |
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if (ret) { |
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dev_err(dev, "Can't add APB EHB data clear action\n"); |
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return ERR_PTR(ret); |
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} |
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apb->dev = dev; |
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atomic_set(&apb->count, 0); |
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platform_set_drvdata(pdev, apb); |
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return apb; |
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} |
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static int bt1_apb_request_regs(struct bt1_apb *apb) |
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{ |
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struct platform_device *pdev = to_platform_device(apb->dev); |
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void __iomem *regs; |
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regs = devm_platform_ioremap_resource_byname(pdev, "ehb"); |
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if (IS_ERR(regs)) { |
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dev_err(apb->dev, "Couldn't map APB EHB registers\n"); |
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return PTR_ERR(regs); |
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} |
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apb->regs = devm_regmap_init_mmio(apb->dev, regs, &bt1_apb_regmap_cfg); |
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if (IS_ERR(apb->regs)) { |
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dev_err(apb->dev, "Couldn't create APB EHB regmap\n"); |
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return PTR_ERR(apb->regs); |
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} |
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apb->res = devm_platform_ioremap_resource_byname(pdev, "nodev"); |
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if (IS_ERR(apb->res)) |
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dev_err(apb->dev, "Couldn't map reserved region\n"); |
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return PTR_ERR_OR_ZERO(apb->res); |
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} |
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static int bt1_apb_request_rst(struct bt1_apb *apb) |
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{ |
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int ret; |
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apb->prst = devm_reset_control_get_optional_exclusive(apb->dev, "prst"); |
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if (IS_ERR(apb->prst)) { |
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dev_warn(apb->dev, "Couldn't get reset control line\n"); |
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return PTR_ERR(apb->prst); |
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} |
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ret = reset_control_deassert(apb->prst); |
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if (ret) |
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dev_err(apb->dev, "Failed to deassert the reset line\n"); |
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return ret; |
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} |
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static void bt1_apb_disable_clk(void *data) |
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{ |
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struct bt1_apb *apb = data; |
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clk_disable_unprepare(apb->pclk); |
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} |
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static int bt1_apb_request_clk(struct bt1_apb *apb) |
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{ |
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int ret; |
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apb->pclk = devm_clk_get(apb->dev, "pclk"); |
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if (IS_ERR(apb->pclk)) { |
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dev_err(apb->dev, "Couldn't get APB clock descriptor\n"); |
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return PTR_ERR(apb->pclk); |
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} |
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ret = clk_prepare_enable(apb->pclk); |
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if (ret) { |
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dev_err(apb->dev, "Couldn't enable the APB clock\n"); |
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return ret; |
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} |
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ret = devm_add_action_or_reset(apb->dev, bt1_apb_disable_clk, apb); |
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if (ret) { |
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dev_err(apb->dev, "Can't add APB EHB clocks disable action\n"); |
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return ret; |
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} |
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apb->rate = clk_get_rate(apb->pclk); |
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if (!apb->rate) { |
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dev_err(apb->dev, "Invalid clock rate\n"); |
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return -EINVAL; |
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} |
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return 0; |
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} |
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static void bt1_apb_clear_irq(void *data) |
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{ |
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struct bt1_apb *apb = data; |
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regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_MASK, 0); |
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} |
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static int bt1_apb_request_irq(struct bt1_apb *apb) |
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{ |
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struct platform_device *pdev = to_platform_device(apb->dev); |
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int ret; |
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apb->irq = platform_get_irq(pdev, 0); |
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if (apb->irq < 0) |
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return apb->irq; |
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ret = devm_request_irq(apb->dev, apb->irq, bt1_apb_isr, IRQF_SHARED, |
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"bt1-apb", apb); |
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if (ret) { |
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dev_err(apb->dev, "Couldn't request APB EHB IRQ\n"); |
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return ret; |
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} |
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ret = devm_add_action(apb->dev, bt1_apb_clear_irq, apb); |
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if (ret) { |
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dev_err(apb->dev, "Can't add APB EHB IRQs clear action\n"); |
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return ret; |
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} |
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/* Unmask IRQ and clear it' pending flag. */ |
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regmap_update_bits(apb->regs, APB_EHB_ISR, |
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APB_EHB_ISR_PENDING | APB_EHB_ISR_MASK, |
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APB_EHB_ISR_MASK); |
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return 0; |
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} |
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static ssize_t count_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct bt1_apb *apb = dev_get_drvdata(dev); |
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return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&apb->count)); |
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} |
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static DEVICE_ATTR_RO(count); |
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static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct bt1_apb *apb = dev_get_drvdata(dev); |
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unsigned long timeout; |
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int ret; |
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u32 n; |
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ret = regmap_read(apb->regs, APB_EHB_TIMEOUT, &n); |
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if (ret) |
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return ret; |
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timeout = bt1_apb_n_to_timeout_us(apb, n); |
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return scnprintf(buf, PAGE_SIZE, "%lu\n", timeout); |
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} |
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static ssize_t timeout_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *buf, size_t count) |
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{ |
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struct bt1_apb *apb = dev_get_drvdata(dev); |
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unsigned long timeout; |
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int ret; |
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u32 n; |
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if (kstrtoul(buf, 0, &timeout) < 0) |
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return -EINVAL; |
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n = bt1_apb_timeout_to_n_us(apb, timeout); |
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n = clamp(n, APB_EHB_TIMEOUT_MIN, APB_EHB_TIMEOUT_MAX); |
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ret = regmap_write(apb->regs, APB_EHB_TIMEOUT, n); |
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return ret ?: count; |
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} |
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static DEVICE_ATTR_RW(timeout); |
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static ssize_t inject_error_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return scnprintf(buf, PAGE_SIZE, "Error injection: nodev irq\n"); |
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} |
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static ssize_t inject_error_store(struct device *dev, |
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struct device_attribute *attr, |
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const char *data, size_t count) |
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{ |
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struct bt1_apb *apb = dev_get_drvdata(dev); |
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/* |
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* Either dummy read from the unmapped address in the APB IO area |
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* or manually set the IRQ status. |
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*/ |
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if (sysfs_streq(data, "nodev")) |
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readl(apb->res); |
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else if (sysfs_streq(data, "irq")) |
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regmap_update_bits(apb->regs, APB_EHB_ISR, APB_EHB_ISR_PENDING, |
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APB_EHB_ISR_PENDING); |
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else |
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return -EINVAL; |
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return count; |
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} |
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static DEVICE_ATTR_RW(inject_error); |
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static struct attribute *bt1_apb_sysfs_attrs[] = { |
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&dev_attr_count.attr, |
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&dev_attr_timeout.attr, |
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&dev_attr_inject_error.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(bt1_apb_sysfs); |
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static void bt1_apb_remove_sysfs(void *data) |
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{ |
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struct bt1_apb *apb = data; |
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device_remove_groups(apb->dev, bt1_apb_sysfs_groups); |
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} |
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static int bt1_apb_init_sysfs(struct bt1_apb *apb) |
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{ |
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int ret; |
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ret = device_add_groups(apb->dev, bt1_apb_sysfs_groups); |
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if (ret) { |
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dev_err(apb->dev, "Failed to create EHB APB sysfs nodes\n"); |
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return ret; |
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} |
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ret = devm_add_action_or_reset(apb->dev, bt1_apb_remove_sysfs, apb); |
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if (ret) |
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dev_err(apb->dev, "Can't add APB EHB sysfs remove action\n"); |
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return ret; |
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} |
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static int bt1_apb_probe(struct platform_device *pdev) |
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{ |
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struct bt1_apb *apb; |
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int ret; |
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apb = bt1_apb_create_data(pdev); |
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if (IS_ERR(apb)) |
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return PTR_ERR(apb); |
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ret = bt1_apb_request_regs(apb); |
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if (ret) |
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return ret; |
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ret = bt1_apb_request_rst(apb); |
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if (ret) |
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return ret; |
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ret = bt1_apb_request_clk(apb); |
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if (ret) |
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return ret; |
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ret = bt1_apb_request_irq(apb); |
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if (ret) |
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return ret; |
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ret = bt1_apb_init_sysfs(apb); |
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if (ret) |
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return ret; |
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return 0; |
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} |
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static const struct of_device_id bt1_apb_of_match[] = { |
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{ .compatible = "baikal,bt1-apb" }, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(of, bt1_apb_of_match); |
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static struct platform_driver bt1_apb_driver = { |
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.probe = bt1_apb_probe, |
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.driver = { |
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.name = "bt1-apb", |
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.of_match_table = bt1_apb_of_match |
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} |
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}; |
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module_platform_driver(bt1_apb_driver); |
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MODULE_AUTHOR("Serge Semin <[email protected]>"); |
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MODULE_DESCRIPTION("Baikal-T1 APB-bus driver"); |
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MODULE_LICENSE("GPL v2");
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