lkml.org 
[lkml]   [2021]   [Nov]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 2/8] bus: fsl-mc: handle DMA config deferral in ACPI case
Hi Laurentiu

On Thu, Jul 15, 2021 at 05:07:12PM +0300, laurentiu.tudor@nxp.com wrote:
> From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
>
> ACPI DMA configure API may return a defer status code, so handle it.
> On top of this, move the MC firmware resume after the DMA setup
> is completed to avoid crashing due to DMA setup not being done yet or
> being deferred.
>
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>

I saw regressions on my Honeycomb LX2 (NXP LX2060A) when I switched to
v5.15. It seems like it results in so many sMMU errors that the system
cannot function correctly (it's only about a 75% chance the system will
boot to GUI and even if it does boot successfully the system will hang
up soon after).

Bisect took me up a couple of blind alleys (mostly due to unrelated boot
problems in v5.14-rc2) by eventually led me to this patch as the cause.
Applying/unapplying this patch to a v5.14-rc3 tree will provoke/fix the
problem and reverting it against v5.15 also resolves the problem.

Is there some specific firmware version required for this patch to work
correctly?


Daniel.


PS: Below is the revert I applied to the v5.15 kernel (after
a fairly simple merge conflict fix)

From 4162b64e4f361a6a773e065b592dbc5493202524 Mon Sep 17 00:00:00 2001
From: Daniel Thompson <daniel.thompson@linaro.org>
Date: Thu, 11 Nov 2021 16:50:25 +0000
Subject: [PATCH] Revert "bus: fsl-mc: handle DMA config deferral in ACPI case"

This reverts commit d31e7fe20a2251f87adc6ecefbdaf25e6961ce74 because
it was causing regressions on my Honeycomb LX2 (NXP LX2060A).

All kernels where the problem manifests (as either a boot hang or a desktop
hang) issue the following messages in vast number:

~~~
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm-smmu arm-smmu.0.auto: Unhandled context fault: fsr=0x402, iova=0x23e0000100, fsynr=0x20040, cbfrsynra=0x4000, cb=0
arm_smmu_context_fault: 1697259 callbacks suppressed
~~~

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
---
drivers/bus/fsl-mc/fsl-mc-bus.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index 8fd4a356a86e..429bacc7de20 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -1130,6 +1130,18 @@ static int fsl_mc_bus_probe(struct platform_device *pdev)
}

if (mc->fsl_mc_regs) {
+ /*
+ * Some bootloaders pause the MC firmware before booting the
+ * kernel so that MC will not cause faults as soon as the
+ * SMMU probes due to the fact that there's no configuration
+ * in place for MC.
+ * At this point MC should have all its SMMU setup done so make
+ * sure it is resumed.
+ */
+ writel(readl(mc->fsl_mc_regs + FSL_MC_GCR1) &
+ (~(GCR1_P1_STOP | GCR1_P2_STOP)),
+ mc->fsl_mc_regs + FSL_MC_GCR1);
+
if (IS_ENABLED(CONFIG_ACPI) && !dev_of_node(&pdev->dev)) {
mc_stream_id = readl(mc->fsl_mc_regs + FSL_MC_FAPR);
/*
@@ -1143,25 +1155,11 @@ static int fsl_mc_bus_probe(struct platform_device *pdev)
error = acpi_dma_configure_id(&pdev->dev,
DEV_DMA_COHERENT,
&mc_stream_id);
- if (error == -EPROBE_DEFER)
- return error;
if (error)
dev_warn(&pdev->dev,
"failed to configure dma: %d.\n",
error);
}
-
- /*
- * Some bootloaders pause the MC firmware before booting the
- * kernel so that MC will not cause faults as soon as the
- * SMMU probes due to the fact that there's no configuration
- * in place for MC.
- * At this point MC should have all its SMMU setup done so make
- * sure it is resumed.
- */
- writel(readl(mc->fsl_mc_regs + FSL_MC_GCR1) &
- (~(GCR1_P1_STOP | GCR1_P2_STOP)),
- mc->fsl_mc_regs + FSL_MC_GCR1);
}

/*
--
2.33.0
\
 
 \ /
  Last update: 2021-11-11 18:24    [W:0.160 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site