Because suspending to RAM may lose the register values, they are restored
on resume. This is currently done unconditionally because there is
currently no way to know (from the driver) whether they have really been
lost or are still valid. Writing MR also pings the watchdog and this may
not be what is expected so add a comment explaining why it happens.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Because the only way to use the driver is to have a device tree enabling
it, pdev->dev.of_node will never be NULL. Remove the unnecessary check.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
WDT_MR and WDT_CR must not updated within three slow clock periods after
the last ping (write to WDT_CR or WDT_MR). Ensure enough time has elapsed
before writing those registers.
wdt_write() waits for 4 periods to ensure at least 3 edges are seen by the
IP.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Wenyou.Yang <wenyou.yang@microchip.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The datasheet states: "When setting the WDDIS bit, and while it is set, the
fields WDV and WDD must not be modified."
Because the whole configuration is already cached inside .mr, wait for the
user to enable the watchdog to configure it so it is enabled and configured
at the same time (what the IP is actually expecting).
When the watchdog is already enabled, it is not an issue to reconfigure it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Wenyou.Yang <wenyou.yang@microchip.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
When resuming for the deepest state on sama5d2, it is necessary to restore
MR as the registers are lost.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
.config is used to cache a part of WDT_MR at probe time and is not used
afterwards. Instead of doing that, actually cache MR and avoid reading it
every time it is modified.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Declare watchdog_ops structures as const as they are only stored in the
ops field of a watchdog_device structure. This field is of type const, so
watchdog_ops structures having this property can be made const too.
Done using Coccinelle:
@r disable optional_qualifier@
identifier x;
position p;
@@
static struct watchdog_ops x@p={...};
@ok@
struct watchdog_device w;
identifier r.x;
position p;
@@
w.ops=&x@p;
@bad@
position p != {r.p,ok.p};
identifier r.x;
@@
x@p
@depends on !bad disable optional_qualifier@
identifier r.x;
@@
+const
struct watchdog_ops x;
File size details before and after patching.
First line of every .o file shows the file size before patching
and second line shows the size after patching.
text data bss dec hex filename
1340 544 0 1884 75c drivers/watchdog/bcm_kona_wdt.o
1436 440 0 1876 754 drivers/watchdog/bcm_kona_wdt.o
1176 544 4 1724 6bc drivers/watchdog/digicolor_wdt.o
1272 440 4 1716 6b4 drivers/watchdog/digicolor_wdt.o
925 580 89 1594 63a drivers/watchdog/ep93xx_wdt.o
1021 476 89 1586 632 drivers/watchdog/ep93xx_wdt.o
4932 288 17 5237 1475 drivers/watchdog/s3c2410_wdt.o
5028 192 17 5237 1475 drivers/watchdog/s3c2410_wdt.o
1977 292 1 2270 8de drivers/watchdog/sama5d4_wdt.o
2073 196 1 2270 8de drivers/watchdog/sama5d4_wdt.o
1375 484 1 1860 744 drivers/watchdog/sirfsoc_wdt.o
1471 380 1 1852 73c drivers/watchdog/sirfsoc_wdt.o
Size remains the same for the files drivers/watchdog/diag288_wdt.o
drivers/watchdog/asm9260_wdt.o and drivers/watchdog/atlas7_wdt.o
The following .o files did not compile:
drivers/watchdog/sun4v_wdt.o, drivers/watchdog/sbsa_gwdt.o,
drivers/watchdog/rt2880_wdt.o, drivers/watchdog/booke_wdt.o
drivers/watchdog/mt7621_wdt.o
Signed-off-by: Bhumika Goyal <bhumirks@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
From SAMA5D4, the watchdog timer is upgrated with a new feature,
which is describled as in the datasheet, "WDT_MR can be written
until a LOCKMR command is issued in WDT_CR".
That is to say, as long as the bootstrap and u-boot don't issue
a LOCKMR command, WDT_MR can be written more than once in the driver.
So the SAMA5D4 watchdog driver's implementation is different from
the at91sam9260 watchdog driver implemented in file at91sam9_wdt.c.
The user application open the device file to enable the watchdog timer
hardware, and close to disable it, and set the watchdog timer timeout
by seting WDV and WDD fields of WDT_MR register, and ping the watchdog
by issuing WDRSTT command to WDT_CR register with hard-coded key.
Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Alexandre Belloni
Bhumika Goyal
Wenyou Yang