On Wed, Nov 12, 2014 at 7:18 AM, <Naidu.Tellapati@xxxxxxxxxx> wrote:
> From: Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>
>
> This commit adds support for ImgTec PowerDown Controller Watchdog Timer.
>
> Signed-off-by: Jude Abraham <Jude.Abraham@xxxxxxxxxx>
> Signed-off-by: Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index d0107d4..13fb1b2 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index c569ec8..467973c 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
These two diffs are full of unrelated changes for some reason.
> diff --git a/drivers/watchdog/imgpdc_wdt.c b/drivers/watchdog/imgpdc_wdt.c
> new file mode 100644
> index 0000000..df9ff1c
> --- /dev/null
> +++ b/drivers/watchdog/imgpdc_wdt.c
> @@ -0,0 +1,388 @@
> +/*
> + * 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/module.h>
> +#include <linux/watchdog.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/interrupt.h>
> +#include <linux/log2.h>
> +#include <linux/slab.h>
#includes should be sorted in alphabetical order.
> +/* registers */
> +#define PDC_WD_SW_RESET 0x000
> +#define PDC_WD_CONFIG 0x004
> +#define PDC_WD_TICKLE1 0x008
> +#define PDC_WD_TICKLE2 0x00c
> +#define PDC_WD_IRQ_STATUS 0x010
> +#define PDC_WD_IRQ_CLEAR 0x014
> +#define PDC_WD_IRQ_EN 0x018
> +
> +/* field masks */
> +#define PDC_WD_CONFIG_REMIND 0x00001f00
> +#define PDC_WD_CONFIG_REMIND_SHIFT 8
> +#define PDC_WD_CONFIG_DELAY 0x0000001f
> +#define PDC_WD_CONFIG_DELAY_SHIFT 0
> +#define PDC_WD_TICKLE_STATUS 0x00000007
> +#define PDC_WD_TICKLE_STATUS_SHIFT 0
> +#define PDC_WD_IRQ_REMIND 0x00000001
> +
> +/* constants */
> +#define PDC_WD_TICKLE1_MAGIC 0xabcd1234
> +#define PDC_WD_TICKLE2_MAGIC 0x4321dcba
> +#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 */
Perhaps put the register field masks/shifts #define next to their
corresponding register #define?
Also, I prefer to #define the unshifted mask, but I'm not sure there's
any rule about that.
> +/* timeout in seconds */
> +#define PDC_WD_MIN_TIMEOUT 1
> +#define PDC_WD_MAX_TIMEOUT 131072
> +#define PDC_WD_DEFAULT_TIMEOUT 64
> +#define PDC_WD_DEFAULT_PRETIMEOUT PDC_WD_MAX_TIMEOUT
> +#define MIN_TIMEOUT_SHIFT 14 /* Clock rate 32768Hz=2^(14+1)*/
The input clock is not fixed at 32kHz. I believe it can be configured
to run at a different rate.
> +static int timeout = PDC_WD_DEFAULT_TIMEOUT;
> +static int pretimeout = PDC_WD_DEFAULT_PRETIMEOUT;
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +
> +struct pdc_wdt_dev {
> + struct watchdog_device wdt_dev;
> + int irq;
> + struct clk *clk;
> + void __iomem *base;
> + unsigned int pretimeout;
> +};
> +
> +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 &= ~BIT(31);
This should be a #define, e.g. 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);
> +
> + if (new_timeout < PDC_WD_MIN_TIMEOUT ||
> + new_timeout > PDC_WD_MAX_TIMEOUT)
> + return -EINVAL;
> +
> + 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);
> +
> + /* number of 32.768KHz clocks, 2^(n+1) (14 is 1 sec) */
> + val &= ~PDC_WD_CONFIG_DELAY;
> + val |= (new_timeout + MIN_TIMEOUT_SHIFT) << PDC_WD_CONFIG_DELAY_SHIFT;
> + writel(val, wdt->base + PDC_WD_CONFIG);
Like I mentioned above, I don't think the input clock is fixed at
32kHz. You need to program the right value based on the input clock's
rate.
> +
> + return 0;
> +}
> +
> +static int pdc_wdt_set_pretimeout(struct watchdog_device *wdt_dev,
> + unsigned int new_pretimeout)
> +{
> + int delay;
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + /*
> + * Pretimeout is measured in seconds before main timeout.
> + * Subtract and round it once, and it will effectively change
> + * if the main timeout is changed.
> + */
> + delay = wdt->wdt_dev.timeout;
> + if (!new_pretimeout)
> + new_pretimeout = PDC_WD_MAX_TIMEOUT;
> + else if (new_pretimeout > 0 && new_pretimeout < delay)
> + new_pretimeout = delay - new_pretimeout;
> + else
> + return -EINVAL;
> +
> + pretimeout = new_pretimeout;
> + new_pretimeout = ilog2(new_pretimeout);
> + val = readl(wdt->base + PDC_WD_CONFIG);
> +
> + /* number of 32.768KHz clocks, 2^(n+1) (14 is 1 sec) */
> + val &= ~PDC_WD_CONFIG_REMIND;
> + val |= (new_pretimeout + MIN_TIMEOUT_SHIFT)
> + << PDC_WD_CONFIG_REMIND_SHIFT;
> + writel(val, wdt->base + PDC_WD_CONFIG);
> + wdt->pretimeout = pretimeout;
> +
> + return 0;
> +}
> +
> +/* Start the watchdog timer (delay should already be set */
> +static int pdc_wdt_start(struct watchdog_device *wdt_dev)
> +{
> + int ret;
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + ret = pdc_wdt_set_timeout(&wdt->wdt_dev, wdt->wdt_dev.timeout);
> + if (ret < 0)
> + return ret;
> +
> + val = readl(wdt->base + PDC_WD_CONFIG);
> + val |= BIT(31);
> + writel(val, wdt->base + PDC_WD_CONFIG);
> +
> + return 0;
> +}
> +
> +static long pdc_wdt_ioctl(struct watchdog_device *wdt_dev,
> + unsigned int cmd, unsigned long arg)
> +{
> + int ret = -ENOIOCTLCMD;
> + unsigned int new_pretimeout;
> + void __user *argp = (void __user *)arg;
> + int __user *p = argp;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + switch (cmd) {
> + case WDIOC_SETPRETIMEOUT:
> + if (get_user(new_pretimeout, p))
> + return -EFAULT;
> +
> + ret = pdc_wdt_set_pretimeout(wdt_dev, new_pretimeout);
> + if (ret < 0)
> + return ret;
> +
> + /* fallthrough */
> + case WDIOC_GETPRETIMEOUT:
> + ret = put_user(wdt->pretimeout, (int __user *)arg);
> + break;
> + }
> +
> + return ret;
> +}
I'm not sure what the point of this pre-timeout stuff is. It looks
like it's just used to trigger an interrupt, which we then just
silently ACK. Perhaps it can be removed, along with the interrupt
handling?
> +static irqreturn_t pdc_wdt_isr(int irq, void *dev_id)
> +{
> + struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(dev_id);
> + unsigned int stat = readl(pdc_wdt->base + PDC_WD_IRQ_STATUS);
> + /*
> + * The behaviour of the remind interrupt should depend on what userland
> + * asks for, either do nothing, panic the system or inform userland.
> + * Unfortunately this is not part of the main linux interface, and is
> + * currently implemented only in the ipmi watchdog driver (in
> + * drivers/char). This could be added at a later time.
> + */
> + writel(stat, pdc_wdt->base + PDC_WD_IRQ_CLEAR);
> + return IRQ_HANDLED;
> +}
> +
> +static struct watchdog_info pdc_wdt_info = {
> + .options = WDIOF_SETTIMEOUT |
> + WDIOF_KEEPALIVEPING |
> + WDIOF_PRETIMEOUT |
> + WDIOF_MAGICCLOSE,
> + .identity = "PDC Watchdog",
> +};
> +
> +/* 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,
> + .ioctl = pdc_wdt_ioctl,
> +};
> +
> +static int pdc_wdt_probe(struct platform_device *pdev)
> +{
> + int ret, val, irq;
> + 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;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev, "cannot find wdt IRQ resource\n");
> + return irq;
> + }
> +
> + 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->clk = devm_clk_get(&pdev->dev, "wdt");
> + if (IS_ERR(pdc_wdt->clk)) {
> + dev_err(&pdev->dev, "failed to get the clock.\n");
> + return PTR_ERR(pdc_wdt->clk);
> + }
> +
> + ret = clk_prepare_enable(pdc_wdt->clk);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "could not prepare or enable wdt clock.\n");
> + return ret;
> + }
Like I said in the binding doc, I think there are two clocks you need
to get and enable here.
> + pdc_wdt->wdt_dev.info = &pdc_wdt_info;
> + pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
> + pdc_wdt->wdt_dev.timeout = PDC_WD_DEFAULT_TIMEOUT;
> + pdc_wdt->wdt_dev.max_timeout = PDC_WD_MAX_TIMEOUT;
> + pdc_wdt->wdt_dev.min_timeout = PDC_WD_MIN_TIMEOUT;
> + pdc_wdt->wdt_dev.parent = &pdev->dev;
> +
> + watchdog_init_timeout(&pdc_wdt->wdt_dev, timeout, &pdev->dev);
> +
> + /* Enable remind interrupts */
> + writel(PDC_WD_IRQ_REMIND, pdc_wdt->base + PDC_WD_IRQ_EN);
> + pdc_wdt_stop(&pdc_wdt->wdt_dev);
> + /* Set timeouts before userland has a chance to start the timer */
> + pdc_wdt_set_timeout(&pdc_wdt->wdt_dev, timeout);
> + pdc_wdt_set_pretimeout(&pdc_wdt->wdt_dev, pretimeout);
> +
> + /* Find what caused the last reset */
> + val = readl(pdc_wdt->base + PDC_WD_TICKLE1);
> + val = (val & PDC_WD_TICKLE_STATUS) >> 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;
> + }
Set pdc_wdt->wdt_dev.bootstatus based on this value?
> +
> + 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) {
> + clk_disable_unprepare(pdc_wdt->clk);
> + return ret;
> + }
> +
> + ret = devm_request_irq(&pdev->dev, irq, pdc_wdt_isr,
> + IRQ_TYPE_LEVEL_HIGH, dev_name(&pdev->dev), pdev);
> + if (ret) {
> + watchdog_unregister_device(&pdc_wdt->wdt_dev);
> + clk_disable_unprepare(pdc_wdt->clk);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int pdc_wdt_remove(struct platform_device *pdev)
> +{
> + struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
> +
> + watchdog_unregister_device(&pdc_wdt->wdt_dev);
> + clk_disable_unprepare(pdc_wdt->clk);
Probably should disable the watchdog as well.
> + watchdog_set_drvdata(&pdc_wdt->wdt_dev, NULL);
Not necessary.
> +
> + return 0;
> +}
> +
> +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 const struct of_device_id pdc_wdt_match[] = {
> + { .compatible = "img,pistachio-pdc-wdt" },
> + {}
> +};
> +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_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout,
> + "PDC watchdog timer delay in seconds ("
> + __MODULE_STRING(PDC_WD_MIN_TIMEOUT)" <= timeout <= "
> + __MODULE_STRING(PDC_WD_MAX_TIMEOUT)
> + "; default = " __MODULE_STRING(PDC_WD_DEFAULT_TIMEOUT) ")");
> +
> +module_param(pretimeout, int, 0);
> +MODULE_PARM_DESC(pretimeout,
> + "PDC watchdog timer remind in seconds ("
> + __MODULE_STRING(PDC_WD_MIN_TIMEOUT)" <= pretimeout <= "
> + __MODULE_STRING(PDC_WD_MAX_TIMEOUT)
> + "; default = " __MODULE_STRING(PDC_WD_DEFAULT_PRETIMEOUT) ")");
> +
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout,
> + "Watchdog cannot be stopped once started (default = "
> + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Maybe put this module_param stuff up where their corresponding
variables are defined?
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Jude Abraham <Jude.Abraham@xxxxxxxxxx>");
> +MODULE_AUTHOR("Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
> +MODULE_ALIAS("platform:img_pdc_wdt");
This driver probes via DT, so I don't think the MODULE_ALIAS is necessary.
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
