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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Xilinx window watchdog timer driver.
- *
- * Author(s): Michal Simek <michal.simek@xilinx.com>
- * Ashok Reddy Soma <ashokred@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 <dm/device_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_plat {
- 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;
- ret = clk_enable(&wdt->clk);
- if (ret) {
- 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_plat *plat = dev_get_plat(dev);
- struct xlnx_wwdt_priv *wdt = dev_get_priv(dev);
- dev_dbg(dev, "%s: Probing wdt%u\n", __func__, dev_seq(dev));
- 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 = plat->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_of_to_plat(struct udevice *dev)
- {
- struct xlnx_wwdt_plat *plat = dev_get_plat(dev);
- plat->enable_once = dev_read_u32_default(dev, "xlnx,wdt-enable-once",
- 0);
- dev_dbg(dev, "wdt-enable-once %d\n", plat->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 = sizeof(struct xlnx_wwdt_priv),
- .plat_auto = sizeof(struct xlnx_wwdt_plat),
- .of_to_plat = xlnx_wwdt_of_to_plat,
- .ops = &xlnx_wwdt_ops,
- };
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