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Message-Id: <20240618222403.464872-3-prabhakar.mahadev-lad.rj@bp.renesas.com>
Date: Tue, 18 Jun 2024 23:24:03 +0100
From: Prabhakar <prabhakar.csengg@...il.com>
To: Wim Van Sebroeck <wim@...ux-watchdog.org>,
Guenter Roeck <linux@...ck-us.net>,
Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
Geert Uytterhoeven <geert+renesas@...der.be>,
Magnus Damm <magnus.damm@...il.com>,
Wolfram Sang <wsa+renesas@...g-engineering.com>
Cc: linux-watchdog@...r.kernel.org,
devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-renesas-soc@...r.kernel.org,
Prabhakar <prabhakar.csengg@...il.com>,
Biju Das <biju.das.jz@...renesas.com>,
Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: [PATCH 2/2] watchdog: Add Watchdog Timer driver for RZ/V2H(P)
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Add Watchdog Timer driver for RZ/V2H(P) SoC.
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
---
drivers/watchdog/Kconfig | 8 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/rzv2h_wdt.c | 248 +++++++++++++++++++++++++++++++++++
3 files changed, 257 insertions(+)
create mode 100644 drivers/watchdog/rzv2h_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 85eea38dbdf4..3f7bcc10ccc2 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -938,6 +938,14 @@ config RENESAS_RZG2LWDT
This driver adds watchdog support for the integrated watchdogs in the
Renesas RZ/G2L SoCs. These watchdogs can be used to reset a system.
+config RENESAS_RZV2HWDT
+ tristate "Renesas RZ/V2H(P) WDT Watchdog"
+ depends on ARCH_RENESAS || COMPILE_TEST
+ select WATCHDOG_CORE
+ help
+ This driver adds watchdog support for the integrated watchdogs in the
+ Renesas RZ/V2H(P) SoCs. These watchdogs can be used to reset a system.
+
config ASPEED_WATCHDOG
tristate "Aspeed BMC watchdog support"
depends on ARCH_ASPEED || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2d1117564f5b..295909a1b3b9 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -86,6 +86,7 @@ obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o
obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o
+obj-$(CONFIG_RENESAS_RZV2HWDT) += rzv2h_wdt.o
obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c
new file mode 100644
index 000000000000..08f97b4bab7f
--- /dev/null
+++ b/drivers/watchdog/rzv2h_wdt.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Renesas RZ/V2H(P) WDT Watchdog Driver
+ *
+ * Copyright (C) 2024 Renesas Electronics Corporation.
+ */
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/units.h>
+#include <linux/watchdog.h>
+
+#define WDTRR 0x00 /* RW, 8 */
+#define WDTCR 0x02 /* RW, 16 */
+#define WDTRCR 0x06 /* RW, 8 */
+
+#define WDTCR_TOPS_1024 0x00
+#define WDTCR_TOPS_16384 0x03
+
+#define WDTCR_CKS_CLK_1 0x00
+#define WDTCR_CKS_CLK_256 0x50
+
+#define WDTCR_RPES_0 0x300
+#define WDTCR_RPES_75 0x000
+
+#define WDTCR_RPSS_25 0x00
+#define WDTCR_RPSS_100 0x3000
+
+#define WDTRCR_RSTIRQS BIT(7)
+
+#define CLOCK_DIV_BY_256 256
+
+#define WDT_DEFAULT_TIMEOUT 60U
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct rzv2h_wdt_priv {
+ void __iomem *base;
+ struct watchdog_device wdev;
+ struct reset_control *rstc;
+ unsigned long oscclk_rate;
+};
+
+static u32 rzv2h_wdt_get_cycle_usec(struct rzv2h_wdt_priv *priv,
+ unsigned long cycle,
+ u16 wdttime)
+{
+ int clock_division_ratio;
+ u64 timer_cycle_us;
+
+ clock_division_ratio = CLOCK_DIV_BY_256;
+
+ timer_cycle_us = clock_division_ratio * (wdttime + 1) * MICRO;
+
+ return div64_ul(timer_cycle_us, cycle);
+}
+
+static int rzv2h_wdt_ping(struct watchdog_device *wdev)
+{
+ struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ unsigned long delay;
+
+ writeb(0x0, priv->base + WDTRR);
+ writeb(0xFF, priv->base + WDTRR);
+
+ /*
+ * Refreshing the down-counter requires up to 4 cycles
+ * of the signal for counting
+ */
+ delay = 4 * rzv2h_wdt_get_cycle_usec(priv, priv->oscclk_rate, 0);
+ udelay(delay);
+
+ return 0;
+}
+
+static void rzv2h_wdt_setup(struct watchdog_device *wdev, u16 wdtcr)
+{
+ struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+ writew(wdtcr, priv->base + WDTCR);
+
+ /* LSI needs RSTIRQS to be cleared */
+ writeb(readb(priv->base + WDTRCR) & ~WDTRCR_RSTIRQS, priv->base + WDTRCR);
+}
+
+static int rzv2h_wdt_start(struct watchdog_device *wdev)
+{
+ pm_runtime_get_sync(wdev->parent);
+
+ /*
+ * WDTCR
+ * - CKS[7:4] - Clock Division Ratio Select - 0101b: oscclk/256
+ * - RPSS[13:12] - Window Start Position Select - 11b: 100%
+ * - RPES[9:8] - Window End Position Select - 11b: 0%
+ * - TOPS[1:0] - Timeout Period Select - 11b: 16384 cycles (3FFFh)
+ */
+ rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_256 | WDTCR_RPSS_100 |
+ WDTCR_RPES_0 | WDTCR_TOPS_16384);
+
+ rzv2h_wdt_ping(wdev);
+
+ return 0;
+}
+
+static int rzv2h_wdt_stop(struct watchdog_device *wdev)
+{
+ struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev);
+
+ pm_runtime_put(wdev->parent);
+ reset_control_reset(priv->rstc);
+
+ return 0;
+}
+
+static const struct watchdog_info rzv2h_wdt_ident = {
+ .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
+ .identity = "Renesas RZ/V2H WDT Watchdog",
+};
+
+static int rzv2h_wdt_restart(struct watchdog_device *wdev,
+ unsigned long action, void *data)
+{
+ rzv2h_wdt_stop(wdev);
+
+ pm_runtime_get_sync(wdev->parent);
+
+ /*
+ * WDTCR
+ * - CKS[7:4] - Clock Division Ratio Select - 0000b: oscclk/1
+ * - RPSS[13:12] - Window Start Position Select - 00b: 25%
+ * - RPES[9:8] - Window End Position Select - 00b: 75%
+ * - TOPS[1:0] - Timeout Period Select - 00b: 1024 cycles (03FFh)
+ */
+ rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_1 | WDTCR_RPSS_25 |
+ WDTCR_RPES_75 | WDTCR_TOPS_1024);
+
+ rzv2h_wdt_ping(wdev);
+
+ return 0;
+}
+
+static const struct watchdog_ops rzv2h_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = rzv2h_wdt_start,
+ .stop = rzv2h_wdt_stop,
+ .ping = rzv2h_wdt_ping,
+ .restart = rzv2h_wdt_restart,
+};
+
+static void rzv2h_wdt_reset_assert(void *data)
+{
+ struct reset_control *rstc = data;
+
+ reset_control_assert(rstc);
+}
+
+static int rzv2h_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rzv2h_wdt_priv *priv;
+ struct clk *oscclk;
+ unsigned long rate;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ /* Get watchdog oscclk clock */
+ oscclk = clk_get(&pdev->dev, "oscclk");
+ if (IS_ERR(oscclk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(oscclk),
+ "no oscclk");
+
+ priv->oscclk_rate = clk_get_rate(oscclk);
+ clk_put(oscclk);
+ if (!priv->oscclk_rate)
+ return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0");
+
+ priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(priv->rstc))
+ return dev_err_probe(&pdev->dev, PTR_ERR(priv->rstc),
+ "failed to get cpg reset");
+
+ ret = reset_control_deassert(priv->rstc);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to deassert");
+ ret = devm_add_action_or_reset(&pdev->dev,
+ rzv2h_wdt_reset_assert,
+ priv->rstc);
+ if (ret < 0)
+ return ret;
+
+ rate = priv->oscclk_rate / 256;
+ priv->wdev.max_hw_heartbeat_ms = (1000 * 16383) / rate;
+ dev_dbg(dev, "max hw timeout of %dms\n",
+ priv->wdev.max_hw_heartbeat_ms);
+
+ priv->wdev.min_timeout = 1;
+ priv->wdev.timeout = WDT_DEFAULT_TIMEOUT;
+ priv->wdev.info = &rzv2h_wdt_ident;
+ priv->wdev.ops = &rzv2h_wdt_ops;
+ priv->wdev.parent = dev;
+ watchdog_set_drvdata(&priv->wdev, priv);
+ watchdog_set_nowayout(&priv->wdev, nowayout);
+ watchdog_stop_on_unregister(&priv->wdev);
+
+ ret = watchdog_init_timeout(&priv->wdev, 0, dev);
+ if (ret)
+ dev_warn(dev, "Specified timeout invalid, using default");
+
+ ret = devm_pm_runtime_enable(&pdev->dev);
+ if (ret)
+ return ret;
+
+ return devm_watchdog_register_device(&pdev->dev, &priv->wdev);
+}
+
+static const struct of_device_id rzv2h_wdt_ids[] = {
+ { .compatible = "renesas,r9a09g057-wdt", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rzv2h_wdt_ids);
+
+static struct platform_driver rzv2h_wdt_driver = {
+ .driver = {
+ .name = "rzv2h_wdt",
+ .of_match_table = rzv2h_wdt_ids,
+ },
+ .probe = rzv2h_wdt_probe,
+};
+module_platform_driver(rzv2h_wdt_driver);
+MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>");
+MODULE_DESCRIPTION("Renesas RZ/V2H(P) WDT Watchdog Driver");
--
2.34.1
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