From: Shreenidhi Shedi imshedi@gmail.com

This IP can be found on Zynq and ZynqMP devices. The driver was tested with reset-on-timeout; feature.

Also adding WATCHDOG symbol to Kconfig because it is required.

Signed-off-by: Shreenidhi Shedi imshedi@gmail.com Signed-off-by: Michal Simek michal.simek@xilinx.com ---

drivers/watchdog/Kconfig | 11 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/cdns_wdt.c | 276 ++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 288 insertions(+) create mode 100644 drivers/watchdog/cdns_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index fc46b6774d57..f5df53b115f1 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -1,5 +1,8 @@ menu "Watchdog Timer Support"

+config WATCHDOG + bool + config HW_WATCHDOG bool

@@ -78,4 +81,12 @@ config WDT_ORION Select this to enable Orion watchdog timer, which can be found on some Marvell Armada chips.

+config WDT_CDNS + bool "Cadence watchdog timer support" + depends on WDT + select WATCHDOG + help + Select this to enable Cadence watchdog timer, which can be found on some + Xilinx Microzed Platform. + endmenu diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index ab6a6b79e1d7..4b97df3ab67b 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -22,3 +22,4 @@ obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o obj-$(CONFIG_WDT_BCM6345) += bcm6345_wdt.o obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o obj-$(CONFIG_WDT_ORION) += orion_wdt.o +obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o diff --git a/drivers/watchdog/cdns_wdt.c b/drivers/watchdog/cdns_wdt.c new file mode 100644 index 000000000000..12def7d27393 --- /dev/null +++ b/drivers/watchdog/cdns_wdt.c @@ -0,0 +1,276 @@ +/* + * Cadence WDT driver - Used by Xilinx Zynq + * Reference: Linux kernel Cadence watchdog driver. + * + * Author(s): Shreenidhi Shedi yesshedi@gmail.com + * + * SPDX-License-Identifier: GPL-2.0 + */ + +#include <common.h> +#include <dm.h> +#include <wdt.h> +#include <clk.h> +#include <linux/io.h> + +DECLARE_GLOBAL_DATA_PTR; + +struct cdns_regs { + u32 zmr; /* WD Zero mode register, offset - 0x0 */ + u32 ccr; /* Counter Control Register offset - 0x4 */ + u32 restart; /* Restart key register, offset - 0x8 */ + u32 status; /* Status Register, offset - 0xC */ +}; + +struct cdns_wdt_priv { + bool rst; + u32 timeout; + void __iomem *reg; + struct cdns_regs *regs; +}; + +#define CDNS_WDT_DEFAULT_TIMEOUT 10 + +/* Supports 1 - 516 sec */ +#define CDNS_WDT_MIN_TIMEOUT 1 +#define CDNS_WDT_MAX_TIMEOUT 516 + +/* Restart key */ +#define CDNS_WDT_RESTART_KEY 0x00001999 + +/* Counter register access key */ +#define CDNS_WDT_REGISTER_ACCESS_KEY 0x00920000 + +/* Counter value divisor */ +#define CDNS_WDT_COUNTER_VALUE_DIVISOR 0x1000 + +/* Clock prescaler value and selection */ +#define CDNS_WDT_PRESCALE_64 64 +#define CDNS_WDT_PRESCALE_512 512 +#define CDNS_WDT_PRESCALE_4096 4096 +#define CDNS_WDT_PRESCALE_SELECT_64 1 +#define CDNS_WDT_PRESCALE_SELECT_512 2 +#define CDNS_WDT_PRESCALE_SELECT_4096 3 + +/* Input clock frequency */ +#define CDNS_WDT_CLK_75MHZ 75000000 + +/* Counter maximum value */ +#define CDNS_WDT_COUNTER_MAX 0xFFF + +/********************* Register Map **********************************/ + +/* + * Zero Mode Register - This register controls how the time out is indicated + * and also contains the access code to allow writes to the register (0xABC). + */ +#define CDNS_WDT_ZMR_WDEN_MASK 0x00000001 /* Enable the WDT */ +#define CDNS_WDT_ZMR_RSTEN_MASK 0x00000002 /* Enable the reset output */ +#define CDNS_WDT_ZMR_IRQEN_MASK 0x00000004 /* Enable IRQ output */ +#define CDNS_WDT_ZMR_RSTLEN_16 0x00000030 /* Reset pulse of 16 pclk cycles */ +#define CDNS_WDT_ZMR_ZKEY_VAL 0x00ABC000 /* Access key, 0xABC << 12 */ + +/* + * Counter Control register - This register controls how fast the timer runs + * and the reset value and also contains the access code to allow writes to + * the register. + */ +#define CDNS_WDT_CCR_CRV_MASK 0x00003FFC /* Counter reset value */ + +/* Write access to Registers */ +static inline void cdns_wdt_writereg(u32 *addr, u32 val) +{ + writel(val, addr); +} + +/** + * cdns_wdt_reset - Reload the watchdog timer (i.e. pat the watchdog). + * + * @dev: Watchdog device + * + * Write the restart key value (0x00001999) to the restart register. + * + * Return: Always 0 + */ +static int32_t cdns_wdt_reset(struct udevice *dev) +{ + struct cdns_wdt_priv *priv = dev_get_priv(dev); + + debug("%s\n", __func__); + + cdns_wdt_writereg(&priv->regs->restart, CDNS_WDT_RESTART_KEY); + + return 0; +} + +/** + * cdns_wdt_start - Enable and start the watchdog. + * + * @dev: Watchdog device + * @timeout: Timeout value + * @flags: Driver flags + * + * The counter value is calculated according to the formula: + * count = (timeout * clock) / prescaler + 1. + * + * The calculated count is divided by 0x1000 to obtain the field value + * to write to counter control register. + * + * Clears the contents of prescaler and counter reset value. Sets the + * prescaler to 4096 and the calculated count and access key + * to write to CCR Register. + * + * Sets the WDT (WDEN bit) and either the Reset signal(RSTEN bit) + * or Interrupt signal(IRQEN) with a specified cycles and the access + * key to write to ZMR Register. + * + * Return: Upon success 0, failure -1. + */ +static int cdns_wdt_start(struct udevice *dev, u64 timeout, ulong flags) +{ + ulong clk_f; + u32 count, prescaler, ctrl_clksel, data = 0; + struct clk clock; + struct cdns_wdt_priv *priv = dev_get_priv(dev); + + if (clk_get_by_index(dev, 0, &clock) < 0) { + dev_err(dev, "failed to get clock\n"); + return -1; + } + + clk_f = clk_get_rate(&clock); + if (IS_ERR_VALUE(clk_f)) { + dev_err(dev, "failed to get rate\n"); + return -1; + } + + debug("%s: CLK_FREQ %ld, timeout %lld\n", __func__, clk_f, timeout); + + if ((timeout < CDNS_WDT_MIN_TIMEOUT) || + (timeout > CDNS_WDT_MAX_TIMEOUT)) { + timeout = priv->timeout; + } + + if (clk_f <= CDNS_WDT_CLK_75MHZ) { + prescaler = CDNS_WDT_PRESCALE_512; + ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_512; + } else { + prescaler = CDNS_WDT_PRESCALE_4096; + ctrl_clksel = CDNS_WDT_PRESCALE_SELECT_4096; + } + + /* + * Counter value divisor to obtain the value of + * counter reset to be written to control register. + */ + count = (timeout * (clk_f / prescaler)) / + CDNS_WDT_COUNTER_VALUE_DIVISOR + 1; + + if (count > CDNS_WDT_COUNTER_MAX) + count = CDNS_WDT_COUNTER_MAX; + + cdns_wdt_writereg(&priv->regs->zmr, CDNS_WDT_ZMR_ZKEY_VAL); + + count = (count << 2) & CDNS_WDT_CCR_CRV_MASK; + + /* Write counter access key first to be able write to register */ + data = count | CDNS_WDT_REGISTER_ACCESS_KEY | ctrl_clksel; + cdns_wdt_writereg(&priv->regs->ccr, data); + + data = CDNS_WDT_ZMR_WDEN_MASK | CDNS_WDT_ZMR_RSTLEN_16 | + CDNS_WDT_ZMR_ZKEY_VAL; + + /* Reset on timeout if specified in device tree. */ + if (priv->rst) { + data |= CDNS_WDT_ZMR_RSTEN_MASK; + data &= ~CDNS_WDT_ZMR_IRQEN_MASK; + } else { + data &= ~CDNS_WDT_ZMR_RSTEN_MASK; + data |= CDNS_WDT_ZMR_IRQEN_MASK; + } + + cdns_wdt_writereg(&priv->regs->zmr, data); + cdns_wdt_writereg(&priv->regs->restart, CDNS_WDT_RESTART_KEY); + + return 0; +} + +/** + * cdns_wdt_stop - Stop the watchdog. + * + * @dev: Watchdog device + * + * Read the contents of the ZMR register, clear the WDEN bit in the register + * and set the access key for successful write. + * + * Return: Always 0 + */ +static int32_t cdns_wdt_stop(struct udevice *dev) +{ + struct cdns_wdt_priv *priv = dev_get_priv(dev); + + cdns_wdt_writereg(&priv->regs->zmr, + CDNS_WDT_ZMR_ZKEY_VAL & (~CDNS_WDT_ZMR_WDEN_MASK)); + + return 0; +} + +/** + * cdns_wdt_probe - Probe call for the device. + * + * @dev: Handle to the udevice structure. + * + * Return: Always 0. + */ +static int32_t cdns_wdt_probe(struct udevice *dev) +{ + struct cdns_wdt_priv *priv = dev_get_priv(dev); + + debug("%s: Probing wdt%u\n", __func__, dev->seq); + + priv->reg = ioremap((u32)priv->regs, sizeof(struct cdns_regs)); + + cdns_wdt_stop(dev); + + return 0; +} + +static int32_t cdns_wdt_ofdata_to_platdata(struct udevice *dev) +{ + int node = dev_of_offset(dev); + struct cdns_wdt_priv *priv = dev_get_priv(dev); + + priv->regs = devfdt_get_addr_ptr(dev); + if (IS_ERR(priv->regs)) + return PTR_ERR(priv->regs); + + priv->timeout = fdtdec_get_int(gd->fdt_blob, node, "timeout-sec", + CDNS_WDT_DEFAULT_TIMEOUT); + + priv->rst = fdtdec_get_bool(gd->fdt_blob, node, "reset-on-timeout"); + + debug("%s: timeout %d, reset %d\n", __func__, priv->timeout, priv->rst); + + return 0; +} + +static const struct wdt_ops cdns_wdt_ops = { + .start = cdns_wdt_start, + .reset = cdns_wdt_reset, + .stop = cdns_wdt_stop, +}; + +static const struct udevice_id cdns_wdt_ids[] = { + { .compatible = "cdns,wdt-r1p2" }, + {} +}; + +U_BOOT_DRIVER(cdns_wdt) = { + .name = "cdns_wdt", + .id = UCLASS_WDT, + .of_match = cdns_wdt_ids, + .probe = cdns_wdt_probe, + .priv_auto_alloc_size = sizeof(struct cdns_wdt_priv), + .ofdata_to_platdata = cdns_wdt_ofdata_to_platdata, + .ops = &cdns_wdt_ops, +};