diff options
Diffstat (limited to 'drivers/watchdog/xilinx_wwdt.c')
| -rw-r--r-- | drivers/watchdog/xilinx_wwdt.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/watchdog/xilinx_wwdt.c b/drivers/watchdog/xilinx_wwdt.c new file mode 100644 index 0000000000..d271e2e8d6 --- /dev/null +++ b/drivers/watchdog/xilinx_wwdt.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Window watchdog device driver for Xilinx Versal WWDT + * + * Copyright (C) 2022 - 2023, Advanced Micro Devices, Inc. + */ + +#include <linux/clk.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/math64.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +/* Max timeout is calculated at 100MHz source clock */ +#define XWWDT_DEFAULT_TIMEOUT 42 +#define XWWDT_MIN_TIMEOUT 1 + +/* Register offsets for the WWDT device */ +#define XWWDT_MWR_OFFSET 0x00 +#define XWWDT_ESR_OFFSET 0x04 +#define XWWDT_FCR_OFFSET 0x08 +#define XWWDT_FWR_OFFSET 0x0c +#define XWWDT_SWR_OFFSET 0x10 + +/* Master Write Control Register Masks */ +#define XWWDT_MWR_MASK BIT(0) + +/* Enable and Status Register Masks */ +#define XWWDT_ESR_WINT_MASK BIT(16) +#define XWWDT_ESR_WSW_MASK BIT(8) +#define XWWDT_ESR_WEN_MASK BIT(0) + +#define XWWDT_CLOSE_WINDOW_PERCENT 50 + +static int wwdt_timeout; +static int closed_window_percent; + +module_param(wwdt_timeout, int, 0); +MODULE_PARM_DESC(wwdt_timeout, + "Watchdog time in seconds. (default=" + __MODULE_STRING(XWWDT_DEFAULT_TIMEOUT) ")"); +module_param(closed_window_percent, int, 0); +MODULE_PARM_DESC(closed_window_percent, + "Watchdog closed window percentage. (default=" + __MODULE_STRING(XWWDT_CLOSE_WINDOW_PERCENT) ")"); +/** + * struct xwwdt_device - Watchdog device structure + * @base: base io address of WDT device + * @spinlock: spinlock for IO register access + * @xilinx_wwdt_wdd: watchdog device structure + * @freq: source clock frequency of WWDT + * @close_percent: Closed window percent + */ +struct xwwdt_device { + void __iomem *base; + spinlock_t spinlock; /* spinlock for register handling */ + struct watchdog_device xilinx_wwdt_wdd; + unsigned long freq; + u32 close_percent; +}; + +static int xilinx_wwdt_start(struct watchdog_device *wdd) +{ + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); + struct watchdog_device *xilinx_wwdt_wdd = &xdev->xilinx_wwdt_wdd; + u64 time_out, closed_timeout, open_timeout; + u32 control_status_reg; + + /* Calculate timeout count */ + time_out = xdev->freq * wdd->timeout; + closed_timeout = div_u64(time_out * xdev->close_percent, 100); + open_timeout = time_out - closed_timeout; + wdd->min_hw_heartbeat_ms = xdev->close_percent * 10 * wdd->timeout; + + spin_lock(&xdev->spinlock); + + iowrite32(XWWDT_MWR_MASK, xdev->base + XWWDT_MWR_OFFSET); + iowrite32(~(u32)XWWDT_ESR_WEN_MASK, xdev->base + XWWDT_ESR_OFFSET); + iowrite32((u32)closed_timeout, xdev->base + XWWDT_FWR_OFFSET); + iowrite32((u32)open_timeout, xdev->base + XWWDT_SWR_OFFSET); + + /* Enable the window watchdog timer */ + control_status_reg = ioread32(xdev->base + XWWDT_ESR_OFFSET); + control_status_reg |= XWWDT_ESR_WEN_MASK; + iowrite32(control_status_reg, xdev->base + XWWDT_ESR_OFFSET); + + spin_unlock(&xdev->spinlock); + + dev_dbg(xilinx_wwdt_wdd->parent, "Watchdog Started!\n"); + + return 0; +} + +static int xilinx_wwdt_keepalive(struct watchdog_device *wdd) +{ + struct xwwdt_device *xdev = watchdog_get_drvdata(wdd); + u32 control_status_reg; + + spin_lock(&xdev->spinlock); + + /* Enable write access control bit for the window watchdog */ + iowrite32(XWWDT_MWR_MASK, xdev->base + XWWDT_MWR_OFFSET); + + /* Trigger restart kick to watchdog */ + control_status_reg = ioread32(xdev->base + XWWDT_ESR_OFFSET); + control_status_reg |= XWWDT_ESR_WSW_MASK; + iowrite32(control_status_reg, xdev->base + XWWDT_ESR_OFFSET); + + spin_unlock(&xdev->spinlock); + + return 0; +} + +static const struct watchdog_info xilinx_wwdt_ident = { + .options = WDIOF_KEEPALIVEPING | + WDIOF_SETTIMEOUT, + .firmware_version = 1, + .identity = "xlnx_window watchdog", +}; + +static const struct watchdog_ops xilinx_wwdt_ops = { + .owner = THIS_MODULE, + .start = xilinx_wwdt_start, + .ping = xilinx_wwdt_keepalive, +}; + +static int xwwdt_probe(struct platform_device *pdev) +{ + struct watchdog_device *xilinx_wwdt_wdd; + struct device *dev = &pdev->dev; + struct xwwdt_device *xdev; + struct clk *clk; + int ret; + + xdev = devm_kzalloc(dev, sizeof(*xdev), GFP_KERNEL); + if (!xdev) + return -ENOMEM; + + xilinx_wwdt_wdd = &xdev->xilinx_wwdt_wdd; + xilinx_wwdt_wdd->info = &xilinx_wwdt_ident; + xilinx_wwdt_wdd->ops = &xilinx_wwdt_ops; + xilinx_wwdt_wdd->parent = dev; + + xdev->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(xdev->base)) + return PTR_ERR(xdev->base); + + clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + xdev->freq = clk_get_rate(clk); + if (!xdev->freq) + return -EINVAL; + + xilinx_wwdt_wdd->min_timeout = XWWDT_MIN_TIMEOUT; + xilinx_wwdt_wdd->timeout = XWWDT_DEFAULT_TIMEOUT; + xilinx_wwdt_wdd->max_hw_heartbeat_ms = 1000 * xilinx_wwdt_wdd->timeout; + + if (closed_window_percent == 0 || closed_window_percent >= 100) + xdev->close_percent = XWWDT_CLOSE_WINDOW_PERCENT; + else + xdev->close_percent = closed_window_percent; + + watchdog_init_timeout(xilinx_wwdt_wdd, wwdt_timeout, &pdev->dev); + spin_lock_init(&xdev->spinlock); + watchdog_set_drvdata(xilinx_wwdt_wdd, xdev); + watchdog_set_nowayout(xilinx_wwdt_wdd, 1); + + ret = devm_watchdog_register_device(dev, xilinx_wwdt_wdd); + if (ret) + return ret; + + dev_info(dev, "Xilinx window watchdog Timer with timeout %ds\n", + xilinx_wwdt_wdd->timeout); + + return 0; +} + +static const struct of_device_id xwwdt_of_match[] = { + { .compatible = "xlnx,versal-wwdt", }, + {}, +}; +MODULE_DEVICE_TABLE(of, xwwdt_of_match); + +static struct platform_driver xwwdt_driver = { + .probe = xwwdt_probe, + .driver = { + .name = "Xilinx window watchdog", + .of_match_table = xwwdt_of_match, + }, +}; + +module_platform_driver(xwwdt_driver); + +MODULE_AUTHOR("Neeli Srinivas <srinivas.neeli@amd.com>"); +MODULE_DESCRIPTION("Xilinx window watchdog driver"); +MODULE_LICENSE("GPL"); |