From 5028358a6a5c3e7fd2d20b190a4205ba3e136ab8 Mon Sep 17 00:00:00 2001 From: Ashok Reddy Soma Date: Wed, 11 Mar 2020 03:06:04 -0600 Subject: [PATCH] watchdog: versal: Add support for Xilinx window watchdog Add support for Xilinx window watchdog, which can be found on Versal platforms. Signed-off-by: Ashok Reddy Soma Reviewed-by: Stefan Roese --- 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 b50652bd85..d8d420f84f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -447,6 +447,7 @@ M: Michal Simek 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: (? + * Ashok Reddy Soma + * + * Copyright (c) 2020, Xilinx Inc. + */ + +#include +#include +#include +#include +#include +#include +#include + +/* 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, +};