watchdog: arm_smc_wdt: add watchdog support

Implement a ARM SMCCC based driver that allow to use
a secure watchdog on the platform.

Signed-off-by: Lionel Debieve <lionel.debieve@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Tested-by: Patrick Delaunay <patrick.delaunay@foss.st.com>

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 668942e977fab4d0c457092dd624b9ed78d91750..a15fbd6cbf7fae19fbb16bc198d430686645312f 100644 (file)
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -361,6 +361,14 @@ config WDT_TANGIER
          Intel Tangier SoC. If you're using a board with Intel Tangier
          SoC, say Y here.
 
+config WDT_ARM_SMC
+       bool "ARM SMC watchdog timer support"
+       depends on WDT && ARM_SMCCC
+       imply WATCHDOG
+       help
+         Select this to enable Arm SMC watchdog timer. This watchdog will manage
+         a watchdog based on ARM SMCCC communication.
+
 config SPL_WDT
        bool "Enable driver model for watchdog timer drivers in SPL"
        depends on SPL_DM

diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index fd795b2e181cb1a0f55256e82a2c302f02a9849b..4da338669e3b5b01ef723250f5b98159a0015a52 100644 (file)
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_$(SPL_TPL_)WDT) += wdt-uclass.o
 obj-$(CONFIG_WDT_SANDBOX) += sandbox_wdt.o
 obj-$(CONFIG_WDT_ALARM_SANDBOX) += sandbox_alarm-wdt.o
 obj-$(CONFIG_WDT_APPLE) += apple_wdt.o
+obj-$(CONFIG_WDT_ARM_SMC) += arm_smc_wdt.o
 obj-$(CONFIG_WDT_ARMADA_37XX) += armada-37xx-wdt.o
 obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o
 obj-$(CONFIG_WDT_AST2600) += ast2600_wdt.o

diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c
new file mode 100644 (file)
index 0000000..0ea4444
--- /dev/null
+++ b/drivers/watchdog/arm_smc_wdt.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ARM Secure Monitor Call watchdog driver
+ * Copyright (C) 2022, STMicroelectronics - All Rights Reserved
+ * This file is based on Linux driver drivers/watchdog/arm_smc_wdt.c
+ */
+
+#define LOG_CATEGORY UCLASS_WDT
+
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <linux/arm-smccc.h>
+#include <linux/psci.h>
+#include <wdt.h>
+
+#define DRV_NAME               "arm_smc_wdt"
+
+#define WDT_TIMEOUT_SECS(TIMEOUT)      ((TIMEOUT) / 1000)
+
+enum smcwd_call {
+       SMCWD_INIT              = 0,
+       SMCWD_SET_TIMEOUT       = 1,
+       SMCWD_ENABLE            = 2,
+       SMCWD_PET               = 3,
+       SMCWD_GET_TIMELEFT      = 4,
+};
+
+struct smcwd_priv_data {
+       u32 smc_id;
+       unsigned int min_timeout;
+       unsigned int max_timeout;
+};
+
+static int smcwd_call(struct udevice *dev, enum smcwd_call call,
+                     unsigned long arg, struct arm_smccc_res *res)
+{
+       struct smcwd_priv_data *priv = dev_get_priv(dev);
+       struct arm_smccc_res local_res;
+
+       if (!res)
+               res = &local_res;
+
+       arm_smccc_smc(priv->smc_id, call, arg, 0, 0, 0, 0, 0, res);
+
+       if (res->a0 == PSCI_RET_NOT_SUPPORTED)
+               return -ENODEV;
+       if (res->a0 == PSCI_RET_INVALID_PARAMS)
+               return -EINVAL;
+       if (res->a0 != PSCI_RET_SUCCESS)
+               return -EIO;
+
+       return 0;
+}
+
+static int smcwd_reset(struct udevice *dev)
+{
+       return smcwd_call(dev, SMCWD_PET, 0, NULL);
+}
+
+static int smcwd_stop(struct udevice *dev)
+{
+       return smcwd_call(dev, SMCWD_ENABLE, 0, NULL);
+}
+
+static int smcwd_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+       struct smcwd_priv_data *priv = dev_get_priv(dev);
+       u64 timeout_sec = WDT_TIMEOUT_SECS(timeout_ms);
+       int err;
+
+       if (timeout_sec < priv->min_timeout || timeout_sec > priv->max_timeout) {
+               dev_err(dev, "Timeout value not supported\n");
+               return -EINVAL;
+       }
+
+       err = smcwd_call(dev, SMCWD_SET_TIMEOUT, timeout_sec, NULL);
+       if (err) {
+               dev_err(dev, "Timeout out configuration failed\n");
+               return err;
+       }
+
+       return smcwd_call(dev, SMCWD_ENABLE, 1, NULL);
+}
+
+static int smcwd_probe(struct udevice *dev)
+{
+       struct smcwd_priv_data *priv = dev_get_priv(dev);
+       struct arm_smccc_res res;
+       int err;
+
+       priv->smc_id = dev_read_u32_default(dev, "arm,smc-id", 0x82003D06);
+
+       err = smcwd_call(dev, SMCWD_INIT, 0, &res);
+       if (err < 0) {
+               dev_err(dev, "Init failed %i\n", err);
+               return err;
+       }
+
+       priv->min_timeout = res.a1;
+       priv->max_timeout = res.a2;
+
+       return 0;
+}
+
+static const struct wdt_ops smcwd_ops = {
+       .start          = smcwd_start,
+       .stop           = smcwd_stop,
+       .reset          = smcwd_reset,
+};
+
+static const struct udevice_id smcwd_dt_ids[] = {
+       { .compatible = "arm,smc-wdt" },
+       {}
+};
+
+U_BOOT_DRIVER(wdt_sandbox) = {
+       .name = "smcwd",
+       .id = UCLASS_WDT,
+       .of_match = smcwd_dt_ids,
+       .priv_auto = sizeof(struct smcwd_priv_data),
+       .probe = smcwd_probe,
+       .ops = &smcwd_ops,
+};