On Fri, Aug 23, 2019 at 12:35:28PM +0300, Ivan Mikhaylov wrote:
> Set WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION into WDT_CLEAR_TIMEOUT_STATUS
> to clear out boot code source and re-enable access to the primary SPI flash
> chip while booted via wdt2 from the alternate chip.
>
> AST2400 datasheet says:
> "In the 2nd flash booting mode, all the address mapping to CS0# would be
> re-directed to CS1#. And CS0# is not accessable under this mode. To access
> CS0#, firmware should clear the 2nd boot mode register in the WDT2 status
> register WDT30.bit[1]."
>
> Signed-off-by: Ivan Mikhaylov <i.mikhaylov@xxxxxxxxx>
> ---
> drivers/watchdog/aspeed_wdt.c | 44 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 43 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
> index cc71861e033a..62bf95cb741f 100644
> --- a/drivers/watchdog/aspeed_wdt.c
> +++ b/drivers/watchdog/aspeed_wdt.c
> @@ -53,6 +53,8 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
> #define WDT_CTRL_ENABLE BIT(0)
> #define WDT_TIMEOUT_STATUS 0x10
> #define WDT_TIMEOUT_STATUS_BOOT_SECONDARY BIT(1)
> +#define WDT_CLEAR_TIMEOUT_STATUS 0x14
> +#define WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION BIT(0)
>
> /*
> * WDT_RESET_WIDTH controls the characteristics of the external pulse (if
> @@ -165,6 +167,42 @@ static int aspeed_wdt_restart(struct watchdog_device *wdd,
> return 0;
> }
>
> +/* access_cs0 shows if cs0 is accessible, hence the reverted bit */
> +static ssize_t access_cs0_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct aspeed_wdt *wdt = dev_get_drvdata(dev);
> +
Unnecessary empty line.
> + uint32_t status = readl(wdt->base + WDT_TIMEOUT_STATUS);
> +
> + return sprintf(buf, "%u\n",
> + !(status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY));
> +}
> +
> +static ssize_t access_cs0_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t size)
> +{
> + struct aspeed_wdt *wdt = dev_get_drvdata(dev);
> + unsigned long val = 0;
Unnecessary initialization.
> +
> + if (kstrtoul(buf, 10, &val))
> + return -EINVAL;
> +
> + if (val)
> + writel(WDT_CLEAR_TIMEOUT_AND_BOOT_CODE_SELECTION,
> + wdt->base + WDT_CLEAR_TIMEOUT_STATUS);
> +
> + return size;
> +}
> +static DEVICE_ATTR_RW(access_cs0);
> +
> +static struct attribute *bswitch_attrs[] = {
> + &dev_attr_access_cs0.attr,
The attribute needs to be documented.
> + NULL
> +};
> +ATTRIBUTE_GROUPS(bswitch);
> +
> static const struct watchdog_ops aspeed_wdt_ops = {
> .start = aspeed_wdt_start,
> .stop = aspeed_wdt_stop,
> @@ -306,8 +344,12 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
> }
>
> status = readl(wdt->base + WDT_TIMEOUT_STATUS);
> - if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY)
> + if (status & WDT_TIMEOUT_STATUS_BOOT_SECONDARY) {
> wdt->wdd.bootstatus = WDIOF_CARDRESET;
> + wdt->wdd.groups = bswitch_groups;
> + }
So the attribute would only exist if the boot was from the secondary
flash, and it would exist even if it wasn't needed (ie on ast2500 /
ast2600) ? Well, if that is what you want, who am I to argue, but
you'll have to document it accordingly. When you do so, please also
document what happens on ast2500 / ast2600 when the attribute exists
and is written.
> +
> + dev_set_drvdata(dev, wdt);
>
> return devm_watchdog_register_device(dev, &wdt->wdd);
> }
> --
> 2.20.1
>
>
