138 lines
3.2 KiB
C
138 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
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/*
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* Copyright (C) 2019, STMicroelectronics - All Rights Reserved
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*/
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#include <common.h>
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#include <clk.h>
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#include <dm.h>
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#include <log.h>
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#include <syscon.h>
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#include <wdt.h>
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#include <asm/io.h>
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#include <linux/bitops.h>
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#include <linux/iopoll.h>
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/* IWDG registers */
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#define IWDG_KR 0x00 /* Key register */
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#define IWDG_PR 0x04 /* Prescaler Register */
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#define IWDG_RLR 0x08 /* ReLoad Register */
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#define IWDG_SR 0x0C /* Status Register */
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/* IWDG_KR register bit mask */
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#define KR_KEY_RELOAD 0xAAAA /* Reload counter enable */
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#define KR_KEY_ENABLE 0xCCCC /* Peripheral enable */
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#define KR_KEY_EWA 0x5555 /* Write access enable */
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/* IWDG_PR register bit values */
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#define PR_256 0x06 /* Prescaler set to 256 */
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/* IWDG_RLR register values */
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#define RLR_MAX 0xFFF /* Max value supported by reload register */
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/* IWDG_SR register bit values */
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#define SR_PVU BIT(0) /* Watchdog prescaler value update */
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#define SR_RVU BIT(1) /* Watchdog counter reload value update */
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struct stm32mp_wdt_priv {
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fdt_addr_t base; /* registers addr in physical memory */
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unsigned long wdt_clk_rate; /* Watchdog dedicated clock rate */
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};
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static int stm32mp_wdt_reset(struct udevice *dev)
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{
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struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
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writel(KR_KEY_RELOAD, priv->base + IWDG_KR);
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return 0;
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}
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static int stm32mp_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
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{
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struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
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int reload;
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u32 val;
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int ret;
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/* Prescaler fixed to 256 */
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reload = timeout_ms * priv->wdt_clk_rate / 256;
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if (reload > RLR_MAX + 1)
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/* Force to max watchdog counter reload value */
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reload = RLR_MAX + 1;
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else if (!reload)
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/* Force to min watchdog counter reload value */
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reload = priv->wdt_clk_rate / 256;
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/* Set prescaler & reload registers */
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writel(KR_KEY_EWA, priv->base + IWDG_KR);
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writel(PR_256, priv->base + IWDG_PR);
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writel(reload - 1, priv->base + IWDG_RLR);
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/* Enable watchdog */
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writel(KR_KEY_ENABLE, priv->base + IWDG_KR);
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/* Wait for the registers to be updated */
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ret = readl_poll_timeout(priv->base + IWDG_SR, val,
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val & (SR_PVU | SR_RVU), CONFIG_SYS_HZ);
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if (ret < 0) {
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pr_err("Updating IWDG registers timeout");
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return -ETIMEDOUT;
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}
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return 0;
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}
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static int stm32mp_wdt_probe(struct udevice *dev)
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{
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struct stm32mp_wdt_priv *priv = dev_get_priv(dev);
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struct clk clk;
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int ret;
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debug("IWDG init\n");
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priv->base = devfdt_get_addr(dev);
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if (priv->base == FDT_ADDR_T_NONE)
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return -EINVAL;
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/* Enable clock */
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ret = clk_get_by_name(dev, "pclk", &clk);
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if (ret)
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return ret;
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ret = clk_enable(&clk);
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if (ret)
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return ret;
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/* Get LSI clock */
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ret = clk_get_by_name(dev, "lsi", &clk);
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if (ret)
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return ret;
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priv->wdt_clk_rate = clk_get_rate(&clk);
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debug("IWDG init done\n");
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return 0;
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}
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static const struct wdt_ops stm32mp_wdt_ops = {
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.start = stm32mp_wdt_start,
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.reset = stm32mp_wdt_reset,
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};
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static const struct udevice_id stm32mp_wdt_match[] = {
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{ .compatible = "st,stm32mp1-iwdg" },
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{ /* sentinel */ }
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};
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U_BOOT_DRIVER(stm32mp_wdt) = {
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.name = "stm32mp-wdt",
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.id = UCLASS_WDT,
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.of_match = stm32mp_wdt_match,
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.priv_auto_alloc_size = sizeof(struct stm32mp_wdt_priv),
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.probe = stm32mp_wdt_probe,
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.ops = &stm32mp_wdt_ops,
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};
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