From bedbef8ad3e75a304af6361af235302bcc61d06b Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 14 May 2024 06:39:01 +0000
Subject: [PATCH] 修改内核路径

---
 kernel/drivers/watchdog/rza_wdt.c |  112 ++++++++++++++++++++++++++++++++++++++++----------------
 1 files changed, 80 insertions(+), 32 deletions(-)

diff --git a/kernel/drivers/watchdog/rza_wdt.c b/kernel/drivers/watchdog/rza_wdt.c
index e618218..7b6c365 100644
--- a/kernel/drivers/watchdog/rza_wdt.c
+++ b/kernel/drivers/watchdog/rza_wdt.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Renesas RZ/A Series WDT Driver
  *
  * Copyright (C) 2017 Renesas Electronics America, Inc.
  * Copyright (C) 2017 Chris Brandt
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License.  See the file "COPYING" in the main directory of this archive
- * for more details.
  */
 
 #include <linux/bitops.h>
@@ -14,6 +11,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/watchdog.h>
 
@@ -34,11 +32,44 @@
 #define WRCSR_RSTE		BIT(6)
 #define WRCSR_CLEAR_WOVF	0xA500	/* special value */
 
+/* The maximum CKS register setting value to get the longest timeout */
+#define CKS_3BIT		0x7
+#define CKS_4BIT		0xF
+
+#define DIVIDER_3BIT		16384	/* Clock divider when CKS = 0x7 */
+#define DIVIDER_4BIT		4194304	/* Clock divider when CKS = 0xF */
+
 struct rza_wdt {
 	struct watchdog_device wdev;
 	void __iomem *base;
 	struct clk *clk;
+	u8 count;
+	u8 cks;
 };
+
+static void rza_wdt_calc_timeout(struct rza_wdt *priv, int timeout)
+{
+	unsigned long rate = clk_get_rate(priv->clk);
+	unsigned int ticks;
+
+	if (priv->cks == CKS_4BIT) {
+		ticks = DIV_ROUND_UP(timeout * rate, DIVIDER_4BIT);
+
+		/*
+		 * Since max_timeout was set in probe, we know that the timeout
+		 * value passed will never calculate to a tick value greater
+		 * than 256.
+		 */
+		priv->count = 256 - ticks;
+
+	} else {
+		/* Start timer with longest timeout */
+		priv->count = 0;
+	}
+
+	pr_debug("%s: timeout set to %u (WTCNT=%d)\n", __func__,
+		 timeout, priv->count);
+}
 
 static int rza_wdt_start(struct watchdog_device *wdev)
 {
@@ -51,13 +82,12 @@
 	readb(priv->base + WRCSR);
 	writew(WRCSR_CLEAR_WOVF, priv->base + WRCSR);
 
-	/*
-	 * Start timer with slowest clock source and reset option enabled.
-	 */
+	rza_wdt_calc_timeout(priv, wdev->timeout);
+
 	writew(WRCSR_MAGIC | WRCSR_RSTE, priv->base + WRCSR);
-	writew(WTCNT_MAGIC | 0, priv->base + WTCNT);
-	writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME | WTSCR_CKS(7),
-	       priv->base + WTCSR);
+	writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
+	writew(WTCSR_MAGIC | WTSCR_WT | WTSCR_TME |
+	       WTSCR_CKS(priv->cks), priv->base + WTCSR);
 
 	return 0;
 }
@@ -75,8 +105,17 @@
 {
 	struct rza_wdt *priv = watchdog_get_drvdata(wdev);
 
-	writew(WTCNT_MAGIC | 0, priv->base + WTCNT);
+	writew(WTCNT_MAGIC | priv->count, priv->base + WTCNT);
 
+	pr_debug("%s: timeout = %u\n", __func__, wdev->timeout);
+
+	return 0;
+}
+
+static int rza_set_timeout(struct watchdog_device *wdev, unsigned int timeout)
+{
+	wdev->timeout = timeout;
+	rza_wdt_start(wdev);
 	return 0;
 }
 
@@ -121,65 +160,74 @@
 	.start = rza_wdt_start,
 	.stop = rza_wdt_stop,
 	.ping = rza_wdt_ping,
+	.set_timeout = rza_set_timeout,
 	.restart = rza_wdt_restart,
 };
 
 static int rza_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct rza_wdt *priv;
-	struct resource *res;
 	unsigned long rate;
 	int ret;
 
-	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	priv->base = devm_ioremap_resource(&pdev->dev, res);
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
-	priv->clk = devm_clk_get(&pdev->dev, NULL);
+	priv->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(priv->clk))
 		return PTR_ERR(priv->clk);
 
 	rate = clk_get_rate(priv->clk);
 	if (rate < 16384) {
-		dev_err(&pdev->dev, "invalid clock rate (%ld)\n", rate);
+		dev_err(dev, "invalid clock rate (%ld)\n", rate);
 		return -ENOENT;
 	}
 
-	/* Assume slowest clock rate possible (CKS=7) */
-	rate /= 16384;
-
 	priv->wdev.info = &rza_wdt_ident,
 	priv->wdev.ops = &rza_wdt_ops,
-	priv->wdev.parent = &pdev->dev;
+	priv->wdev.parent = dev;
 
-	/*
-	 * Since the max possible timeout of our 8-bit count register is less
-	 * than a second, we must use max_hw_heartbeat_ms.
-	 */
-	priv->wdev.max_hw_heartbeat_ms = (1000 * U8_MAX) / rate;
-	dev_dbg(&pdev->dev, "max hw timeout of %dms\n",
-		 priv->wdev.max_hw_heartbeat_ms);
+	priv->cks = (u8)(uintptr_t) of_device_get_match_data(dev);
+	if (priv->cks == CKS_4BIT) {
+		/* Assume slowest clock rate possible (CKS=0xF) */
+		priv->wdev.max_timeout = (DIVIDER_4BIT * U8_MAX) / rate;
+
+	} else if (priv->cks == CKS_3BIT) {
+		/* Assume slowest clock rate possible (CKS=7) */
+		rate /= DIVIDER_3BIT;
+
+		/*
+		 * Since the max possible timeout of our 8-bit count
+		 * register is less than a second, we must use
+		 * max_hw_heartbeat_ms.
+		 */
+		priv->wdev.max_hw_heartbeat_ms = (1000 * U8_MAX) / rate;
+		dev_dbg(dev, "max hw timeout of %dms\n",
+			priv->wdev.max_hw_heartbeat_ms);
+	}
 
 	priv->wdev.min_timeout = 1;
 	priv->wdev.timeout = DEFAULT_TIMEOUT;
 
-	watchdog_init_timeout(&priv->wdev, 0, &pdev->dev);
+	watchdog_init_timeout(&priv->wdev, 0, dev);
 	watchdog_set_drvdata(&priv->wdev, priv);
 
-	ret = devm_watchdog_register_device(&pdev->dev, &priv->wdev);
+	ret = devm_watchdog_register_device(dev, &priv->wdev);
 	if (ret)
-		dev_err(&pdev->dev, "Cannot register watchdog device\n");
+		dev_err(dev, "Cannot register watchdog device\n");
 
 	return ret;
 }
 
 static const struct of_device_id rza_wdt_of_match[] = {
-	{ .compatible = "renesas,rza-wdt", },
+	{ .compatible = "renesas,r7s9210-wdt",	.data = (void *)CKS_4BIT, },
+	{ .compatible = "renesas,rza-wdt",	.data = (void *)CKS_3BIT, },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, rza_wdt_of_match);

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