On Thu, Nov 27, 2014 at 10:24:04AM +0530, Naidu Tellapati wrote:
> This commit adds support for ImgTec PowerDown Controller Watchdog Timer.
>
> Signed-off-by: Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>
> Signed-off-by: Jude.Abraham <Jude.Abraham@xxxxxxxxxx>
> Reviewed-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
> Reviewed-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxx>
> ---
> drivers/watchdog/Kconfig | 11 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/imgpdc_wdt.c | 298 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 310 insertions(+), 0 deletions(-)
> create mode 100644 drivers/watchdog/imgpdc_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index d0107d4..a184f23 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1235,6 +1235,17 @@ config BCM_KONA_WDT_DEBUG
>
> If in doubt, say 'N'.
>
> +config IMGPDC_WDT
> + tristate "Imagination Technologies PDC Watchdog Timer"
> + depends on HAS_IOMEM
> + depends on METAG || MIPS || COMPILE_TEST
> + help
> + Driver for Imagination Technologies PowerDown Controller
> + Watchdog Timer.
> +
> + To compile this driver as a loadable module, choose M here.
> + The module will be called imgpdc_wdt.
> +
> config LANTIQ_WDT
> tristate "Lantiq SoC watchdog"
> depends on LANTIQ
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index c569ec8..d4dfbb4 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -142,6 +142,7 @@ obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
> octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
> obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
> obj-$(CONFIG_RALINK_WDT) += rt2880_wdt.o
> +obj-$(CONFIG_IMGPDC_WDT) += imgpdc_wdt.o
>
> # PARISC Architecture
>
> diff --git a/drivers/watchdog/imgpdc_wdt.c b/drivers/watchdog/imgpdc_wdt.c
> new file mode 100644
> index 0000000..efb00b5
> --- /dev/null
> +++ b/drivers/watchdog/imgpdc_wdt.c
> @@ -0,0 +1,298 @@
> +/*
> + * Imagination Technologies PowerDown Controller Watchdog Timer.
> + *
> + * Copyright (c) 2014 Imagination Technologies Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + *
> + * Based on drivers/watchdog/sunxi_wdt.c Copyright (c) 2013 Carlo Caione
> + * 2012 Henrik Nordstrom
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/log2.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/watchdog.h>
> +
> +/* registers */
> +#define PDC_WD_SW_RESET 0x000
> +
> +#define PDC_WD_CONFIG 0x004
> +#define PDC_WD_CONFIG_ENABLE BIT(31)
> +#define PDC_WD_CONFIG_DELAY_MASK 0x0000001f
> +#define PDC_WD_CONFIG_DELAY_SHIFT 0
> +
> +#define PDC_WD_TICKLE1 0x008
> +#define PDC_WD_TICKLE1_MAGIC 0xabcd1234
> +
> +#define PDC_WD_TICKLE2 0x00c
> +#define PDC_WD_TICKLE2_MAGIC 0x4321dcba
> +
> +#define PDC_WD_TICKLE_STATUS_MASK 0x00000007
> +#define PDC_WD_TICKLE_STATUS_SHIFT 0
> +#define PDC_WD_TICKLE_STATUS_HRESET 0x0 /* Hard reset */
> +#define PDC_WD_TICKLE_STATUS_TIMEOUT 0x1 /* Timeout */
> +#define PDC_WD_TICKLE_STATUS_TICKLE 0x2 /* Tickled incorrectly */
> +#define PDC_WD_TICKLE_STATUS_SRESET 0x3 /* Soft reset */
> +#define PDC_WD_TICKLE_STATUS_USER 0x4 /* User reset */
> +
> +/* timeout in seconds */
> +#define PDC_WD_MIN_TIMEOUT 1
> +#define PDC_WD_DEFAULT_TIMEOUT 64
> +
> +static int timeout = PDC_WD_DEFAULT_TIMEOUT;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout, "PDC watchdog delay in seconds (default 64s)");
It might be better to use __MODULE_STRING(PDC_WD_DEFAULT_TIMEOUT)
to encode the default timeout.
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
> +
> +struct pdc_wdt_dev {
> + struct watchdog_device wdt_dev;
> + struct clk *wdt_clk;
> + struct clk *sys_clk;
> + int min_delay;
> + void __iomem *base;
> +};
> +
> +static int pdc_wdt_keepalive(struct watchdog_device *wdt_dev)
> +{
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + writel(PDC_WD_TICKLE1_MAGIC, wdt->base + PDC_WD_TICKLE1);
> + writel(PDC_WD_TICKLE2_MAGIC, wdt->base + PDC_WD_TICKLE2);
> +
> + return 0;
> +}
> +
> +static int pdc_wdt_stop(struct watchdog_device *wdt_dev)
> +{
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + val = readl(wdt->base + PDC_WD_CONFIG);
> + val &= ~PDC_WD_CONFIG_ENABLE;
> + writel(val, wdt->base + PDC_WD_CONFIG);
> +
> + /* Must tickle to finish the stop */
> + pdc_wdt_keepalive(wdt_dev);
> +
> + return 0;
> +}
> +
> +static int pdc_wdt_set_timeout(struct watchdog_device *wdt_dev,
> + unsigned int new_timeout)
> +{
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + wdt->wdt_dev.timeout = new_timeout;
> + /* round up to the next power of 2 */
> + new_timeout = order_base_2(new_timeout);
> + val = readl(wdt->base + PDC_WD_CONFIG);
> + val &= ~PDC_WD_CONFIG_DELAY_MASK;
> + val |= (new_timeout + wdt->min_delay) << PDC_WD_CONFIG_DELAY_SHIFT;
> + writel(val, wdt->base + PDC_WD_CONFIG);
> +
> + return 0;
> +}
> +
> +/* Start the watchdog timer (delay should already be set) */
> +static int pdc_wdt_start(struct watchdog_device *wdt_dev)
> +{
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + val = readl(wdt->base + PDC_WD_CONFIG);
> + val |= PDC_WD_CONFIG_ENABLE;
> + writel(val, wdt->base + PDC_WD_CONFIG);
> +
> + return 0;
> +}
> +
> +static struct watchdog_info pdc_wdt_info = {
> + .identity = "IMG PDC Watchdog",
> + .options = WDIOF_SETTIMEOUT |
> + WDIOF_KEEPALIVEPING |
> + WDIOF_MAGICCLOSE,
> +};
> +
> +/* Kernel interface */
> +static const struct watchdog_ops pdc_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = pdc_wdt_start,
> + .stop = pdc_wdt_stop,
> + .ping = pdc_wdt_keepalive,
> + .set_timeout = pdc_wdt_set_timeout,
> +};
> +
> +static int pdc_wdt_probe(struct platform_device *pdev)
> +{
> + int ret, val;
> + unsigned long clk_rate;
> + struct resource *res;
> + struct pdc_wdt_dev *pdc_wdt;
> +
> + pdc_wdt = devm_kzalloc(&pdev->dev, sizeof(*pdc_wdt), GFP_KERNEL);
> + if (!pdc_wdt)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + pdc_wdt->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(pdc_wdt->base))
> + return PTR_ERR(pdc_wdt->base);
> +
> + pdc_wdt->sys_clk = devm_clk_get(&pdev->dev, "sys");
> + if (IS_ERR(pdc_wdt->sys_clk)) {
> + dev_err(&pdev->dev, "failed to get the sys clock.\n");
> + ret = PTR_ERR(pdc_wdt->wdt_clk);
sys_clk
> + return ret;
return PTR_ERR(pdc_wdt->sys_clk);
On a higher level, what is sys_clk needed and used for in the first place ?
The need for wdt_clk is obvious, but there is no explanation for the need
of sys_clk, and the bindings file doesn't give a hint either.
> + }
> +
> + pdc_wdt->wdt_clk = devm_clk_get(&pdev->dev, "wdt");
> + if (IS_ERR(pdc_wdt->wdt_clk)) {
> + dev_err(&pdev->dev, "failed to get the wdt clock.\n");
> + ret = PTR_ERR(pdc_wdt->wdt_clk);
> + return ret;
return PTR_ERR(pdc_wdt->wdt_clk);
> + }
> +
> + ret = clk_prepare_enable(pdc_wdt->sys_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "could not prepare or enable sys clock.\n");
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(pdc_wdt->wdt_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "could not prepare or enable wdt clock.\n");
> + goto disable_sys_clk;
I would suggest to drop the '.' in those messages.
> + }
> +
> + /* We use the clock rate to calculate the max timeout */
> + clk_rate = clk_get_rate(pdc_wdt->wdt_clk);
> + if (clk_rate == 0) {
> + dev_err(&pdev->dev, "failed to get clock rate\n");
> + ret = -EINVAL;
> + goto disable_wdt_clk;
> + }
> +
> + if (order_base_2(clk_rate) > PDC_WD_CONFIG_DELAY_MASK + 1) {
> + dev_err(&pdev->dev, "invalid clock rate\n");
> + ret = -EINVAL;
> + goto disable_wdt_clk;
> + }
> +
> + if (order_base_2(clk_rate) == 0)
> + pdc_wdt->wdt_dev.min_timeout = PDC_WD_MIN_TIMEOUT + 1;
> + else
> + pdc_wdt->wdt_dev.min_timeout = PDC_WD_MIN_TIMEOUT;
> +
> + pdc_wdt->min_delay = order_base_2(clk_rate) - 1;
Ultimately this means that min_delay can be smaller than 0,
which makes it quite difficult to validate the rest of the code
to ensure that it handles this case correctly.
Give that a clock rate of 1 is somewhere between highly unlikely and
unreasonable, wouldn't it be much easier to consider it to be invalid
and not try to handle it ?
> +
> + pdc_wdt->wdt_dev.info = &pdc_wdt_info;
> + pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
> + pdc_wdt->wdt_dev.max_timeout =
> + (1 << (PDC_WD_CONFIG_DELAY_MASK - pdc_wdt->min_delay));
> + pdc_wdt->wdt_dev.parent = &pdev->dev;
> +
> + ret = watchdog_init_timeout(&pdc_wdt->wdt_dev, timeout, &pdev->dev);
> + if (ret < 0) {
> + pdc_wdt->wdt_dev.timeout = pdc_wdt->wdt_dev.max_timeout;
> + dev_warn(&pdev->dev,
> + "Initial timeout out of range! setting max timeout\n");
> + }
> +
> + pdc_wdt_stop(&pdc_wdt->wdt_dev);
> +
> + /* Find what caused the last reset */
> + val = readl(pdc_wdt->base + PDC_WD_TICKLE1);
> + val = (val & PDC_WD_TICKLE_STATUS_MASK) >> PDC_WD_TICKLE_STATUS_SHIFT;
> + switch (val) {
> + case PDC_WD_TICKLE_STATUS_TICKLE:
> + case PDC_WD_TICKLE_STATUS_TIMEOUT:
> + pdc_wdt->wdt_dev.bootstatus |= WDIOF_CARDRESET;
> + dev_info(&pdev->dev,
> + "watchdog module last reset due to timeout\n");
> + break;
> + case PDC_WD_TICKLE_STATUS_HRESET:
> + dev_info(&pdev->dev,
> + "watchdog module last reset due to hard reset\n");
> + break;
> + case PDC_WD_TICKLE_STATUS_SRESET:
> + dev_info(&pdev->dev,
> + "watchdog module last reset due to soft reset\n");
> + break;
> + case PDC_WD_TICKLE_STATUS_USER:
> + dev_info(&pdev->dev,
> + "watchdog module last reset due to user reset\n");
> + break;
> + default:
> + dev_info(&pdev->dev,
> + "contains an illegal status code (%08x)\n", val);
> + break;
> + }
> +
> + watchdog_set_nowayout(&pdc_wdt->wdt_dev, nowayout);
> +
> + platform_set_drvdata(pdev, pdc_wdt);
> + watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
> +
> + ret = watchdog_register_device(&pdc_wdt->wdt_dev);
> + if (ret)
> + goto disable_wdt_clk;
> +
> + return 0;
> +
> +disable_wdt_clk:
> + clk_disable_unprepare(pdc_wdt->wdt_clk);
> +disable_sys_clk:
> + clk_disable_unprepare(pdc_wdt->sys_clk);
> + return ret;
> +}
> +
> +static void pdc_wdt_shutdown(struct platform_device *pdev)
> +{
> + struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
> +
> + pdc_wdt_stop(&pdc_wdt->wdt_dev);
> +}
> +
> +static int pdc_wdt_remove(struct platform_device *pdev)
> +{
> + struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
> +
> + pdc_wdt_stop(&pdc_wdt->wdt_dev);
> + watchdog_unregister_device(&pdc_wdt->wdt_dev);
> + clk_disable_unprepare(pdc_wdt->wdt_clk);
> + clk_disable_unprepare(pdc_wdt->sys_clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id pdc_wdt_match[] = {
> + { .compatible = "img,pdc-wdt" },
Will "img" be added to the list of vendor prefixes with some other patch ?
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, pdc_wdt_match);
> +
> +static struct platform_driver pdc_wdt_driver = {
> + .driver = {
> + .name = "imgpdc-wdt",
> + .of_match_table = pdc_wdt_match,
> + },
> + .probe = pdc_wdt_probe,
> + .remove = pdc_wdt_remove,
> + .shutdown = pdc_wdt_shutdown,
> +};
> +module_platform_driver(pdc_wdt_driver);
> +
> +MODULE_AUTHOR("Jude Abraham <Jude.Abraham@xxxxxxxxxx>");
> +MODULE_AUTHOR("Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.7.0.4
>
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