[PATCH 1/2] watchdog: sunxi: support parameterized compatible strings
Chen-Yu Tsai
wens at csie.org
Fri Sep 19 07:00:36 PDT 2014
Hi,
On Fri, Sep 19, 2014 at 12:54 PM, Guenter Roeck <linux at roeck-us.net> wrote:
> On 09/16/2014 07:42 AM, Chen-Yu Tsai wrote:
>>
>> This patch adds support for hardware parameters tied to compatible
>> strings, so similar hardware can reuse the driver.
>>
>> This will be used to support the newer watchdog found in A31 and
>> later SoCs. Differences in the new hardware include separate
>> interrupt lines for each watchdog, and corresponding interrupt
>> control/status registers. Watchdog control registers were also
>> slightly rearranged.
>>
> You might also mention that you replace some iowrite32 with writel.
Ah.... Had that in mind, but forgot about it when finishing the series :(
>> Signed-off-by: Chen-Yu Tsai <wens at csie.org>
>
>
> Have you considered using regmap ? Seems to be an ideal candidate.
I don't follow. Do you mean using regmap to share the interrupt registers
with the timer on sun4i? Otherwise I don't really see a difference.
Am I missing something?
>> ---
>> drivers/watchdog/sunxi_wdt.c | 101
>> ++++++++++++++++++++++++++++++++-----------
>> 1 file changed, 76 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/watchdog/sunxi_wdt.c b/drivers/watchdog/sunxi_wdt.c
>> index 480bb55..a1f7113 100644
>> --- a/drivers/watchdog/sunxi_wdt.c
>> +++ b/drivers/watchdog/sunxi_wdt.c
>> @@ -23,6 +23,7 @@
>> #include <linux/moduleparam.h>
>> #include <linux/notifier.h>
>> #include <linux/of.h>
>> +#include <linux/of_device.h>
>> #include <linux/platform_device.h>
>> #include <linux/reboot.h>
>> #include <linux/types.h>
>> @@ -30,15 +31,11 @@
>>
>> #define WDT_MAX_TIMEOUT 16
>> #define WDT_MIN_TIMEOUT 1
>> -#define WDT_MODE_TIMEOUT(n) ((n) << 3)
>> -#define WDT_TIMEOUT_MASK WDT_MODE_TIMEOUT(0x0F)
>> +#define WDT_TIMEOUT_MASK 0x0F
>>
>> -#define WDT_CTRL 0x00
>> #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1))
>>
>> -#define WDT_MODE 0x04
>> #define WDT_MODE_EN (1 << 0)
>> -#define WDT_MODE_RST_EN (1 << 1)
>>
>> #define DRV_NAME "sunxi-wdt"
>> #define DRV_VERSION "1.0"
>> @@ -46,15 +43,29 @@
>> static bool nowayout = WATCHDOG_NOWAYOUT;
>> static unsigned int timeout = WDT_MAX_TIMEOUT;
>>
>> +/*
>> + * This structure stores the register offsets for different variants
>> + * of Allwinner's watchdog hardware.
>> + */
>> +struct sunxi_wdt_reg {
>> + u8 wdt_ctrl;
>> + u8 wdt_cfg;
>> + u8 wdt_mode;
>> + u8 wdt_timeout_shift;
>> + u8 wdt_reset_mask;
>> + u8 wdt_reset_val;
>> +};
>> +
>> struct sunxi_wdt_dev {
>> struct watchdog_device wdt_dev;
>> void __iomem *wdt_base;
>> + const struct sunxi_wdt_reg *wdt_regs;
>> struct notifier_block restart_handler;
>> };
>>
>> /*
>> * wdt_timeout_map maps the watchdog timer interval value in seconds to
>> - * the value of the register WDT_MODE bit 3:6
>> + * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3
>> *
>> * [timeout seconds] = register value
>> *
>> @@ -82,19 +93,32 @@ static int sunxi_restart_handle(struct notifier_block
>> *this, unsigned long mode,
>> struct
>> sunxi_wdt_dev,
>> restart_handler);
>> void __iomem *wdt_base = sunxi_wdt->wdt_base;
>> + const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
>> + u32 val;
>> +
>> + /* Set system reset function */
>> + val = readl(wdt_base + regs->wdt_cfg);
>> + val &= ~(regs->wdt_reset_mask);
>> + val |= regs->wdt_reset_val;
>> + writel(val, wdt_base + regs->wdt_cfg);
>>
>> - /* Enable timer and set reset bit in the watchdog */
>> - writel(WDT_MODE_EN | WDT_MODE_RST_EN, wdt_base + WDT_MODE);
>> + /* Set lowest timeout and enable watchdog */
>> + val = readl(wdt_base + regs->wdt_mode);
>> + val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
>> + val |= WDT_MODE_EN;
>
>
> I think it would make sense to also define WDT_MODE_EN and
> WDT_TIMEOUT_MASK as configurable, even if not currently needed.
> It is odd to have the shift configurable but not the mask,
> and to have the mode register configurable but not the mode value.
I think keeping these values constants clearly shows that they are
the same and shared among the hardware. Making them configurable
shouldn't impose much penalty, but I'd prefer to keep them as is
until we need to change them.
>> + writel(val, wdt_base + regs->wdt_mode);
>>
>> /*
>> * Restart the watchdog. The default (and lowest) interval
>> * value for the watchdog is 0.5s.
>> */
>> - writel(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
>> + writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
>>
>> while (1) {
>> mdelay(5);
>> - writel(WDT_MODE_EN | WDT_MODE_RST_EN, wdt_base +
>> WDT_MODE);
>> + val = readl(wdt_base + regs->wdt_mode);
>> + val |= WDT_MODE_EN;
>> + writel(val, wdt_base + regs->wdt_mode);
>> }
>> return NOTIFY_DONE;
>> }
>> @@ -103,8 +127,9 @@ static int sunxi_wdt_ping(struct watchdog_device
>> *wdt_dev)
>> {
>> struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
>> void __iomem *wdt_base = sunxi_wdt->wdt_base;
>> + const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
>>
>> - iowrite32(WDT_CTRL_RELOAD, wdt_base + WDT_CTRL);
>> + writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl);
>>
>> return 0;
>> }
>> @@ -114,6 +139,7 @@ static int sunxi_wdt_set_timeout(struct
>> watchdog_device *wdt_dev,
>> {
>> struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
>> void __iomem *wdt_base = sunxi_wdt->wdt_base;
>> + const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
>> u32 reg;
>>
>> if (wdt_timeout_map[timeout] == 0)
>> @@ -121,10 +147,10 @@ static int sunxi_wdt_set_timeout(struct
>> watchdog_device *wdt_dev,
>>
>> sunxi_wdt->wdt_dev.timeout = timeout;
>>
>> - reg = ioread32(wdt_base + WDT_MODE);
>> - reg &= ~WDT_TIMEOUT_MASK;
>> - reg |= WDT_MODE_TIMEOUT(wdt_timeout_map[timeout]);
>> - iowrite32(reg, wdt_base + WDT_MODE);
>> + reg = readl(wdt_base + regs->wdt_mode);
>> + reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift);
>> + reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift;
>> + writel(reg, wdt_base + regs->wdt_mode);
>>
>> sunxi_wdt_ping(wdt_dev);
>>
>> @@ -135,8 +161,9 @@ static int sunxi_wdt_stop(struct watchdog_device
>> *wdt_dev)
>> {
>> struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
>> void __iomem *wdt_base = sunxi_wdt->wdt_base;
>> + const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
>>
>> - iowrite32(0, wdt_base + WDT_MODE);
>> + writel(0, wdt_base + regs->wdt_mode);
>>
>> return 0;
>> }
>> @@ -146,6 +173,7 @@ static int sunxi_wdt_start(struct watchdog_device
>> *wdt_dev)
>> u32 reg;
>> struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev);
>> void __iomem *wdt_base = sunxi_wdt->wdt_base;
>> + const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs;
>> int ret;
>>
>> ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev,
>> @@ -153,9 +181,16 @@ static int sunxi_wdt_start(struct watchdog_device
>> *wdt_dev)
>> if (ret < 0)
>> return ret;
>>
>> - reg = ioread32(wdt_base + WDT_MODE);
>> - reg |= (WDT_MODE_RST_EN | WDT_MODE_EN);
>> - iowrite32(reg, wdt_base + WDT_MODE);
>> + /* Set system reset function */
>> + reg = readl(wdt_base + regs->wdt_cfg);
>> + reg &= ~(regs->wdt_reset_mask);
>> + reg |= ~(regs->wdt_reset_val);
>> + writel(reg, wdt_base + regs->wdt_cfg);
>> +
>> + /* Enable watchdog */
>> + reg = readl(wdt_base + regs->wdt_mode);
>> + reg |= WDT_MODE_EN;
>> + writel(reg, wdt_base + regs->wdt_mode);
>>
>> return 0;
>> }
>> @@ -175,9 +210,25 @@ static const struct watchdog_ops sunxi_wdt_ops = {
>> .set_timeout = sunxi_wdt_set_timeout,
>> };
>>
>> +static const struct sunxi_wdt_reg sun4i_wdt_reg = {
>> + .wdt_ctrl = 0x00,
>> + .wdt_cfg = 0x04,
>> + .wdt_mode = 0x04,
>> + .wdt_timeout_shift = 3,
>> + .wdt_reset_mask = 0x02,
>> + .wdt_reset_val = 0x02,
>> +};
>> +
>> +static const struct of_device_id sunxi_wdt_dt_ids[] = {
>> + { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg
>> },
>> + { /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
>> +
>> static int sunxi_wdt_probe(struct platform_device *pdev)
>> {
>> struct sunxi_wdt_dev *sunxi_wdt;
>> + const struct of_device_id *device;
>> struct resource *res;
>> int err;
>>
>> @@ -187,6 +238,12 @@ static int sunxi_wdt_probe(struct platform_device
>> *pdev)
>>
>> platform_set_drvdata(pdev, sunxi_wdt);
>>
>> + device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev);
>> + if (!device)
>> + return -ENODEV;
>> +
>> + sunxi_wdt->wdt_regs = device->data;
>> +
>> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res);
>> if (IS_ERR(sunxi_wdt->wdt_base))
>> @@ -242,12 +299,6 @@ static void sunxi_wdt_shutdown(struct platform_device
>> *pdev)
>> sunxi_wdt_stop(&sunxi_wdt->wdt_dev);
>> }
>>
>> -static const struct of_device_id sunxi_wdt_dt_ids[] = {
>> - { .compatible = "allwinner,sun4i-a10-wdt" },
>> - { /* sentinel */ }
>> -};
>> -MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids);
>> -
>> static struct platform_driver sunxi_wdt_driver = {
>> .probe = sunxi_wdt_probe,
>> .remove = sunxi_wdt_remove,
>>
Thanks
ChenYu
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