[PATCH v2] watchdog: versal: Add support for Xilinx window watchdog
Michal Simek
michal.simek at xilinx.com
Mon Mar 23 15:47:39 CET 2020
From: Ashok Reddy Soma <ashok.reddy.soma at xilinx.com>
Add support for Xilinx window watchdog, which can be found on
Versal platforms.
Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma at xilinx.com>
Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---
Changes in v2:
- Reverse subject prefixes
- Convert to regmap as was asked
- Rename WWDT_XILINX to WDT_XILINX
MAINTAINERS | 1 +
drivers/watchdog/Kconfig | 9 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/xilinx_wwdt.c | 179 +++++++++++++++++++++++++++++++++
4 files changed, 190 insertions(+)
create mode 100644 drivers/watchdog/xilinx_wwdt.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 92dda40a85df..b14d83475d7c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -447,6 +447,7 @@ M: Michal Simek <michal.simek at xilinx.com>
S: Maintained
T: git https://gitlab.denx.de/u-boot/custodians/u-boot-microblaze.git
F: arch/arm/mach-versal/
+F: drivers/watchdog/xilinx_wwdt.c
N: (?<!uni)versal
ARM VERSATILE EXPRESS DRIVERS
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index cb4da2e3cf88..6cafd243e049 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -185,6 +185,15 @@ config XILINX_TB_WATCHDOG
Select this to enable Xilinx Axi watchdog timer, which can be found on some
Xilinx Microblaze Platforms.
+config WDT_XILINX
+ bool "Xilinx window watchdog timer support"
+ depends on WDT && ARCH_VERSAL
+ select REGMAP
+ imply WATCHDOG
+ help
+ Select this to enable Xilinx window watchdog timer, which can be found on
+ Xilinx Versal Platforms.
+
config WDT_TANGIER
bool "Intel Tangier watchdog timer support"
depends on WDT && INTEL_MID
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 87f92a43b14e..519bbd3a40fc 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_WDT_OMAP3) += omap_wdt.o
obj-$(CONFIG_WDT_SP805) += sp805_wdt.o
obj-$(CONFIG_WDT_STM32MP) += stm32mp_wdt.o
obj-$(CONFIG_WDT_TANGIER) += tangier_wdt.o
+obj-$(CONFIG_WDT_XILINX) += xilinx_wwdt.o
diff --git a/drivers/watchdog/xilinx_wwdt.c b/drivers/watchdog/xilinx_wwdt.c
new file mode 100644
index 000000000000..d8a585a48306
--- /dev/null
+++ b/drivers/watchdog/xilinx_wwdt.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx window watchdog timer driver.
+ *
+ * Author(s): Michal Simek <michal.simek at xilinx.com>
+ * Ashok Reddy Soma <ashokred at xilinx.com>
+ *
+ * Copyright (c) 2020, Xilinx Inc.
+ */
+
+#include <clk.h>
+#include <common.h>
+#include <dm.h>
+#include <regmap.h>
+#include <wdt.h>
+#include <linux/compat.h>
+#include <linux/io.h>
+
+/* Refresh Register Masks */
+#define XWT_WWREF_GWRR_MASK BIT(0) /* Refresh and start new period */
+
+/* Generic Control/Status Register Masks */
+#define XWT_WWCSR_GWEN_MASK BIT(0) /* Enable Bit */
+
+/* Register offsets for the Wdt device */
+#define XWT_WWREF_OFFSET 0x1000 /* Refresh Register */
+#define XWT_WWCSR_OFFSET 0x2000 /* Control/Status Register */
+#define XWT_WWOFF_OFFSET 0x2008 /* Offset Register */
+#define XWT_WWCMP0_OFFSET 0x2010 /* Compare Value Register0 */
+#define XWT_WWCMP1_OFFSET 0x2014 /* Compare Value Register1 */
+#define XWT_WWWRST_OFFSET 0x2FD0 /* Warm Reset Register */
+
+struct xlnx_wwdt_priv {
+ bool enable_once;
+ struct regmap *regs;
+ struct clk clk;
+};
+
+struct xlnx_wwdt_platdata {
+ bool enable_once;
+};
+
+static int xlnx_wwdt_reset(struct udevice *dev)
+{
+ struct xlnx_wwdt_priv *wdt = dev_get_priv(dev);
+
+ regmap_write(wdt->regs, XWT_WWREF_OFFSET, XWT_WWREF_GWRR_MASK);
+
+ return 0;
+}
+
+static int xlnx_wwdt_stop(struct udevice *dev)
+{
+ u32 csr;
+ struct xlnx_wwdt_priv *wdt = dev_get_priv(dev);
+
+ if (wdt->enable_once) {
+ dev_warn(dev, "Can't stop Xilinx watchdog.\n");
+ return -EBUSY;
+ }
+
+ /* Disable the generic watchdog timer */
+ regmap_read(wdt->regs, XWT_WWCSR_OFFSET, &csr);
+ csr &= ~(XWT_WWCSR_GWEN_MASK);
+ regmap_write(wdt->regs, XWT_WWCSR_OFFSET, csr);
+
+ clk_disable(&wdt->clk);
+
+ dev_dbg(dev, "Watchdog disabled!\n");
+
+ return 0;
+}
+
+static int xlnx_wwdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+ int ret;
+ u32 csr;
+ u64 count;
+ unsigned long clock_f;
+ struct xlnx_wwdt_priv *wdt = dev_get_priv(dev);
+
+ clock_f = clk_get_rate(&wdt->clk);
+ if (IS_ERR_VALUE(clock_f)) {
+ dev_err(dev, "failed to get rate\n");
+ return clock_f;
+ }
+
+ dev_dbg(dev, "%s: CLK %ld\n", __func__, clock_f);
+
+ /* Calculate timeout count */
+ count = timeout * clock_f;
+
+ /* clk_enable will return -ENOSYS when it is not implemented */
+ ret = clk_enable(&wdt->clk);
+ if (ret && ret != -ENOSYS) {
+ dev_err(dev, "failed to enable clock\n");
+ return ret;
+ }
+
+ /*
+ * Timeout count is half as there are two windows
+ * first window overflow is ignored (interrupt),
+ * reset is only generated at second window overflow
+ */
+ count = count >> 1;
+
+ /* Disable the generic watchdog timer */
+ regmap_read(wdt->regs, XWT_WWCSR_OFFSET, &csr);
+ csr &= ~(XWT_WWCSR_GWEN_MASK);
+ regmap_write(wdt->regs, XWT_WWCSR_OFFSET, csr);
+
+ /* Set compare and offset registers for generic watchdog timeout */
+ regmap_write(wdt->regs, XWT_WWCMP0_OFFSET, (u32)count);
+ regmap_write(wdt->regs, XWT_WWCMP1_OFFSET, 0);
+ regmap_write(wdt->regs, XWT_WWOFF_OFFSET, (u32)count);
+
+ /* Enable the generic watchdog timer */
+ regmap_read(wdt->regs, XWT_WWCSR_OFFSET, &csr);
+ csr |= (XWT_WWCSR_GWEN_MASK);
+ regmap_write(wdt->regs, XWT_WWCSR_OFFSET, csr);
+
+ return 0;
+}
+
+static int xlnx_wwdt_probe(struct udevice *dev)
+{
+ int ret;
+ struct xlnx_wwdt_platdata *platdata = dev_get_platdata(dev);
+ struct xlnx_wwdt_priv *wdt = dev_get_priv(dev);
+
+ dev_dbg(dev, "%s: Probing wdt%u\n", __func__, dev->seq);
+
+ ret = regmap_init_mem(dev_ofnode(dev), &wdt->regs);
+ if (ret) {
+ dev_dbg(dev, "failed to get regbase of wwdt\n");
+ return ret;
+ }
+
+ wdt->enable_once = platdata->enable_once;
+
+ ret = clk_get_by_index(dev, 0, &wdt->clk);
+ if (ret < 0)
+ dev_err(dev, "failed to get clock\n");
+
+ return ret;
+}
+
+static int xlnx_wwdt_ofdata_to_platdata(struct udevice *dev)
+{
+ struct xlnx_wwdt_platdata *platdata = dev_get_platdata(dev);
+
+ platdata->enable_once = dev_read_u32_default(dev,
+ "xlnx,wdt-enable-once", 0);
+ dev_dbg(dev, "wdt-enable-once %d\n", platdata->enable_once);
+
+ return 0;
+}
+
+static const struct wdt_ops xlnx_wwdt_ops = {
+ .start = xlnx_wwdt_start,
+ .reset = xlnx_wwdt_reset,
+ .stop = xlnx_wwdt_stop,
+};
+
+static const struct udevice_id xlnx_wwdt_ids[] = {
+ { .compatible = "xlnx,versal-wwdt-1.0", },
+ {},
+};
+
+U_BOOT_DRIVER(xlnx_wwdt) = {
+ .name = "xlnx_wwdt",
+ .id = UCLASS_WDT,
+ .of_match = xlnx_wwdt_ids,
+ .probe = xlnx_wwdt_probe,
+ .priv_auto_alloc_size = sizeof(struct xlnx_wwdt_priv),
+ .platdata_auto_alloc_size = sizeof(struct xlnx_wwdt_platdata),
+ .ofdata_to_platdata = xlnx_wwdt_ofdata_to_platdata,
+ .ops = &xlnx_wwdt_ops,
+};
--
2.25.1
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