RE: [RFC v1 4/7] iommu/arm-smmu-v3: Enable HiSilicon erratum 161010701

-----Original Message-----
From: Robin Murphy [mailto:robin.murphy-5wv7dgnIgG8@public.gmane.org]
Sent: Tuesday, May 16, 2017 2:13 PM
To: Shameerali Kolothum Thodi; will.deacon-5wv7dgnIgG8@public.gmane.org;
mark.rutland-5wv7dgnIgG8@public.gmane.org; lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org; hanjun.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org
Cc: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Gabriele Paoloni; John Garry; Linuxarm;
linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org; Wangzhou
(B); Guohanjun (Hanjun Guo); linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org;
devel-E0kO6a4B6psdnm+yROfE0A@public.gmane.org
Subject: Re: [RFC v1 4/7] iommu/arm-smmu-v3: Enable HiSilicon erratum
161010701

On 13/05/17 10:47, shameer wrote:

quoted

This replaces the existing broken_prefetch_cmd quirk using
the new erratum framework.

Signed-off-by: shameer <redacted>
---
 arch/arm64/Kconfig          | 10 +++++++++-
 drivers/iommu/arm-smmu-v3.c | 36 ++++++++++--------------------------
 2 files changed, 19 insertions(+), 27 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a39029b..21d61ff 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -508,8 +508,16 @@ config QCOM_FALKOR_ERRATUM_1009

 	  If unsure, say Y.

-endmenu
+config HISILICON_ERRATUM_161010701
+	bool "HiSilicon erratum 161010701: Skip SMMU Prefetch Cmd"
+	default y
+	help
+	  On HiSilicon Hip06/Hip07 platforms, the SMMU v3 doesn't support

the

quoted

+	  CMD_PREFETCH_CFG. This will skip the prefetch cmd usage.

+	  If unsure, say Y.

We don't need a config. This feature (not to mention others like it) is
runtime-detected, and has effectively zero execution overhead and
negligible Image-size overhead either way; why would anyone ever turn it
off?

This was the side effect of the "framework". Sure will update on next revision.

Thanks,
Shameer
 

Robin.

quoted

+
+endmenu

 choice
 	prompt "Page size"

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-

v3.c

quoted

index f20d5d5..14538cb 100644

--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c

@@ -650,16 +650,6 @@ struct arm_smmu_domain {
 	struct iommu_domain		domain;
 };

-struct arm_smmu_option_prop {
-	u32 opt;
-	const char *prop;
-};
-
-static struct arm_smmu_option_prop arm_smmu_options[] = {
-	{ ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-

cmd" },

quoted

-	{ 0, NULL},
-};
-
 enum smmu_erratum_match_type {
 	se_match_dt,
 };

@@ -677,7 +667,17 @@ struct smmu_erratum_workaround {
 };

 static const struct smmu_erratum_workaround smmu_workarounds[] = {
+#ifdef CONFIG_HISILICON_ERRATUM_161010701
+	{
+		.match_type = se_match_dt,
+		.id = "hisilicon,erratum-161010701",
+		.desc_str = "HiSilicon erratum 161010701",
+		.enable = erratum_skip_prefetch_cmd,
+	},
+#endif
+	{

+	},
 };

 typedef bool (*se_match_fn_t)(const struct smmu_erratum_workaround

*,

quoted

@@ -735,20 +735,6 @@ static struct arm_smmu_domain

*to_smmu_domain(struct iommu_domain *dom)

quoted

 	return container_of(dom, struct arm_smmu_domain, domain);
 }

-static void parse_driver_options(struct arm_smmu_device *smmu)
-{
-	int i = 0;
-
-	do {
-		if (of_property_read_bool(smmu->dev->of_node,
-						arm_smmu_options[i].prop))

{

quoted

-			smmu->options |= arm_smmu_options[i].opt;
-			dev_notice(smmu->dev, "option %s\n",
-				arm_smmu_options[i].prop);
-		}
-	} while (arm_smmu_options[++i].opt);
-}
-
 /* Low-level queue manipulation functions */
 static bool queue_full(struct arm_smmu_queue *q)
 {

@@ -2695,8 +2681,6 @@ static int arm_smmu_device_dt_probe(struct

platform_device *pdev,

quoted

 	else
 		ret = 0;

-	parse_driver_options(smmu);
-
 	smmu_check_workarounds(smmu, se_match_dt, dev->of_node);

 	if (of_dma_is_coherent(dev->of_node))

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