On 06/08/2015 09:05 AM, Fu Wei wrote:
Hi Gurnter
On 3 June 2015 at 01:07, Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
On 06/02/2015 09:55 AM, Fu Wei wrote:
Hi Timur,
Thanks , feedback inline
On 2 June 2015 at 23:32, Timur Tabi <timur@xxxxxxxxxxxxxx> wrote:
On 06/01/2015 11:05 PM, fu.wei@xxxxxxxxxx wrote:
+/*
+ * help functions for accessing 32bit registers of SBSA Generic
Watchdog
+ */
+static void sbsa_gwdt_cf_write(unsigned int reg, u32 val,
+ struct watchdog_device *wdd)
+{
+ struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+ writel_relaxed(val, gwdt->control_base + reg);
+}
+
+static void sbsa_gwdt_rf_write(unsigned int reg, u32 val,
+ struct watchdog_device *wdd)
+{
+ struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+ writel_relaxed(val, gwdt->refresh_base + reg);
+}
+
+static u32 sbsa_gwdt_cf_read(unsigned int reg, struct watchdog_device
*wdd)
+{
+ struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd);
+
+ return readl_relaxed(gwdt->control_base + reg);
+}
I still think you should get rid of these functions and just call
readl_relaxed() and writel_relaxed() every time, but I won't complain
again
if you keep them.
yes, that make sense, and will reduce the size of code, and I think
the code's readability will be OK too.
will try in my next patch,
+static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id)
+{
+ struct sbsa_gwdt *gwdt = (struct sbsa_gwdt *)dev_id;
+ struct watchdog_device *wdd = &gwdt->wdd;
+
+ if (wdd->pretimeout)
+ /* The pretimeout is valid, go panic */
+ panic("SBSA Watchdog pre-timeout");
+ else
+ /* We don't use pretimeout, trigger WS1 now*/
+ sbsa_gwdt_set_wcv(wdd, 0);
I don't like this.
If so, what is your idea ,if pretimeout == 0?
the reason of using WCV as (timout - pretimeout): it can provide the
longer timeout period,
(1)If we use WOR, it can only provide 10s @ 400MHz(max).
as Guenter said earlier, the default timer out for most watchdog will
be 30s, so I think 10s limit will be a little short
(2)we can always program WCV just like ping.
(3)if a timeout arrives, WOR will be use, so use it as pretimeout, but
we still can make this pretimeout longer by programming WCV(I don't
think it's necessary)
The triggering of the hardware reset should never depend
on an interrupt being handled properly.
if this fail, system reset in 1S, because WOR == (1s)
So ?
Even the interrupt routine isn't triggered, (WOR + system counter) --> WCV,
then, sy system reset in 1S.
the hardware reset doesn't depend on an interrupt.
You should always program WCV
correctly in advance. This is especially true since pre-timeout will
probably rarely be used.
always programming WCV is doable. But I absolutely can not agree "
pre-timeout will probably rarely be used"
If so, SBSA watchdog is just a normal watchdog, This use case just
makes this HW useless.
If so, go to use SP805.
you still don't see the importance of this warning and pretimeout to a
real server.
If pretimeout isn't used, why not just set WCV = timeout, WOR = 0 ?
Because if WOR = 0 , according to SBSA, once you want to enable watchdog,
(0 + system counter) --> WCV , then , WS0 and WS1 will be triggered immediately.
we have not a chance(a time slot) to update WCV.
I would have thought that this is exactly what we want if pretimeout is not used.
What am I missing here ?
Guenter
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