On 02/03/2023 6:15 pm, AngeloGioacchino Del Regno wrote:
Il 02/03/23 13:40, Yassine Oudjana ha scritto:
From: Yassine Oudjana <y.oudjana@xxxxxxxxxxxxxx>
Add support for the watchdog timer/top reset generation unit found on
MT6735.
Disable WDT_MODE_IRQ_EN in mtk_wdt_restart in order to make TOPRGU assert
the SYSRST pin instead of issuing an IRQ. This change may be needed in
other
SoCs as well.
Signed-off-by: Yassine Oudjana <y.oudjana@xxxxxxxxxxxxxx>
---
drivers/watchdog/mtk_wdt.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c
index a9c437598e7e..5a7a7b2b3727 100644
--- a/drivers/watchdog/mtk_wdt.c
+++ b/drivers/watchdog/mtk_wdt.c
@@ -10,6 +10,7 @@
*/
#include <dt-bindings/reset/mt2712-resets.h>
+#include <dt-bindings/reset/mediatek,mt6735-wdt.h>
#include <dt-bindings/reset/mediatek,mt6795-resets.h>
#include <dt-bindings/reset/mt7986-resets.h>
#include <dt-bindings/reset/mt8183-resets.h>
@@ -82,6 +83,10 @@ static const struct mtk_wdt_data mt2712_data = {
.toprgu_sw_rst_num = MT2712_TOPRGU_SW_RST_NUM,
};
+static const struct mtk_wdt_data mt6735_data = {
+ .toprgu_sw_rst_num = MT6735_TOPRGU_RST_NUM,
+};
+
static const struct mtk_wdt_data mt6795_data = {
.toprgu_sw_rst_num = MT6795_TOPRGU_SW_RST_NUM,
};
@@ -187,9 +192,15 @@ static int mtk_wdt_restart(struct watchdog_device
*wdt_dev,
{
struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev);
void __iomem *wdt_base;
+ u32 reg;
wdt_base = mtk_wdt->wdt_base;
+ /* Enable reset in order to issue a system reset instead of an
IRQ */
+ reg = readl(wdt_base + WDT_MODE);
+ reg &= ~WDT_MODE_IRQ_EN;
+ writel(reg | WDT_MODE_KEY, wdt_base + WDT_MODE);
This is unnecessary and already done in mtk_wdt_start().
If you think you *require* this snippet, you most likely misconfigured the
devicetree node for your device :-)
Ok so mtk_wdt_start is never called. I'm still not quite sure how the
watchdog works but it seems to me like it's supposed to be started from
userspace. I also see some drivers calling it in probe.
Say I don't want to use the watchdog (which I don't, all I need from
TOPRGU is the resets, I don't care about the watchdog). Not starting the
watchdog means I can't reset the system because all mtk_wdt_restart will
do is make TOPRGU send me an IRQ that I have no use for. According to
the datasheet, setting WDT_MODE_IRQ_EN configures TOPRGU to send an IRQ
on system reset event (either watchdog timeout or software watchdog
reset) while clearing it makes it actually issue a system reset. What
can I do in this case?
