[U-Boot,1/2] x86: baytrail: Fix unstable ACPI S3 resume

Message ID 1507810078-29955-1-git-send-email-bmeng.cn@gmail.com
State Accepted
Delegated to: Bin Meng
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Series
  • [U-Boot,1/2] x86: baytrail: Fix unstable ACPI S3 resume
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Commit Message

Bin Meng Oct. 12, 2017, 12:07 p.m.
It was observed that when booting a Ubuntu 16.04 kernel, doing ACPI
S3 suspend/resume sometimes causes the Ubuntu kernel hang forever.
The issue is however not reproduced with a kernel built from i386/
x86_64 defconfig configuration.

The unstability is actually caused by unexpected interrupts being
generated during the S3 resume. For some unknown reason, FSP (gold4)
for BayTrail configures the GPIO DFX5 PAD to enable level interrupt
(bit 24 and 25). As this pin keeps generating interrupts during an
S3 resume, and there is no IRQ requester in the kernel to handle it,
the kernel seems to hang and does not continue resuming.

Clear the mysterious interrupt bits for this pin.

Reported-by: Stefan Roese <sr@denx.de>
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
---

 arch/x86/cpu/baytrail/valleyview.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

Comments

Stefan Roese Oct. 13, 2017, 11:09 a.m. | #1
On 12.10.2017 14:07, Bin Meng wrote:
> It was observed that when booting a Ubuntu 16.04 kernel, doing ACPI
> S3 suspend/resume sometimes causes the Ubuntu kernel hang forever.
> The issue is however not reproduced with a kernel built from i386/
> x86_64 defconfig configuration.
> 
> The unstability is actually caused by unexpected interrupts being
> generated during the S3 resume. For some unknown reason, FSP (gold4)
> for BayTrail configures the GPIO DFX5 PAD to enable level interrupt
> (bit 24 and 25). As this pin keeps generating interrupts during an
> S3 resume, and there is no IRQ requester in the kernel to handle it,
> the kernel seems to hang and does not continue resuming.
> 
> Clear the mysterious interrupt bits for this pin.

Thanks for working on this. This must have been very tough to debug
and fix.

> Reported-by: Stefan Roese <sr@denx.de>
> Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

Tested-by: Stefan Roese <sr@denx.de>
Reviewed-by: Stefan Roese <sr@denx.de>

Thanks,
Stefan
Bin Meng Oct. 19, 2017, 3:36 a.m. | #2
On Fri, Oct 13, 2017 at 7:09 PM, Stefan Roese <sr@denx.de> wrote:
> On 12.10.2017 14:07, Bin Meng wrote:
>>
>> It was observed that when booting a Ubuntu 16.04 kernel, doing ACPI
>> S3 suspend/resume sometimes causes the Ubuntu kernel hang forever.
>> The issue is however not reproduced with a kernel built from i386/
>> x86_64 defconfig configuration.
>>
>> The unstability is actually caused by unexpected interrupts being
>> generated during the S3 resume. For some unknown reason, FSP (gold4)
>> for BayTrail configures the GPIO DFX5 PAD to enable level interrupt
>> (bit 24 and 25). As this pin keeps generating interrupts during an
>> S3 resume, and there is no IRQ requester in the kernel to handle it,
>> the kernel seems to hang and does not continue resuming.
>>
>> Clear the mysterious interrupt bits for this pin.
>
>
> Thanks for working on this. This must have been very tough to debug
> and fix.
>
>> Reported-by: Stefan Roese <sr@denx.de>
>> Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
>
>
> Tested-by: Stefan Roese <sr@denx.de>
> Reviewed-by: Stefan Roese <sr@denx.de>

applied to u-boot-x86, thanks!

Patch

diff --git a/arch/x86/cpu/baytrail/valleyview.c b/arch/x86/cpu/baytrail/valleyview.c
index c58f6a8..9af1bda 100644
--- a/arch/x86/cpu/baytrail/valleyview.c
+++ b/arch/x86/cpu/baytrail/valleyview.c
@@ -10,6 +10,13 @@ 
 #include <asm/irq.h>
 #include <asm/mrccache.h>
 #include <asm/post.h>
+#include <asm/arch/iomap.h>
+
+/* GPIO SUS */
+#define GPIO_SUS_PAD_BASE	(IO_BASE_ADDRESS + IO_BASE_OFFSET_GPSSUS)
+#define GPIO_SUS_DFX5_CONF0	0x150
+#define BYT_TRIG_LVL		BIT(24)
+#define BYT_TRIG_POS		BIT(25)
 
 #ifndef CONFIG_EFI_APP
 int arch_cpu_init(void)
@@ -33,6 +40,21 @@  int arch_misc_init(void)
 	mrccache_save();
 #endif
 
+	/*
+	 * For some unknown reason, FSP (gold4) for BayTrail configures
+	 * the GPIO DFX5 PAD to enable level interrupt (bit 24 and 25).
+	 * This does not cause any issue when Linux kernel runs w/ or w/o
+	 * the pinctrl driver for BayTrail. However this causes unstable
+	 * S3 resume if the pinctrl driver is included in the kernel build.
+	 * As this pin keeps generating interrupts during an S3 resume,
+	 * and there is no IRQ requester in the kernel to handle it, the
+	 * kernel seems to hang and does not continue resuming.
+	 *
+	 * Clear the mysterious interrupt bits for this pin.
+	 */
+	clrbits_le32(GPIO_SUS_PAD_BASE + GPIO_SUS_DFX5_CONF0,
+		     BYT_TRIG_LVL | BYT_TRIG_POS);
+
 	return 0;
 }