[PATCH 0/2] iommu/ipmmu-vmsa: Disable cache snoop transactions on R-Car Gen3

[PATCH 0/2] iommu/ipmmu-vmsa: Disable cache snoop transactions on R-Car Gen3

[Geert Uytterhoeven]

	Hi Jörg,

According to recent errata, the IOMMU in R-Car Gen3 SoCs does not
support cache snoop transactions for page table walk requests.

Hence this patch series skips the related setup when running on R-Car
Gen3, after doing a customary cleanup of related definitions.

Tested on R-Car H3 ES2.0 with QEMU+KVM and VFIO for EtherAVB.

Thanks!

Geert Uytterhoeven (1):
  iommu/ipmmu-vmsa: Move IMTTBCR_SL0_TWOBIT_* to restore sort order

Hai Nguyen Pham (1):
  iommu/ipmmu-vmsa: Disable cache snoop transactions on R-Car Gen3

 drivers/iommu/ipmmu-vmsa.c | 78 ++++++++++++++++++++------------------
 1 file changed, 41 insertions(+), 37 deletions(-)

-- 
2.17.1

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

[PATCH 1/2] iommu/ipmmu-vmsa: Move IMTTBCR_SL0_TWOBIT_* to restore sort order

[Geert Uytterhoeven]

Move the recently added IMTTBCR_SL0_TWOBIT_* definitions up, to make
sure all IMTTBCR register bit definitions are sorted by decreasing bit
index.  Add comments to make it clear that they exist on R-Car Gen3
only.

Fixes: c295f504fb5a38ab ("iommu/ipmmu-vmsa: Allow two bit SL0")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/iommu/ipmmu-vmsa.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 76a8ec343d53252e..1baabeaddc9cba1b 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -145,15 +145,14 @@ static struct ipmmu_vmsa_device *to_ipmmu(struct device *dev)
 #define IMTTBCR_IRGN0_WT		(2 << 8)
 #define IMTTBCR_IRGN0_WB		(3 << 8)
 #define IMTTBCR_IRGN0_MASK		(3 << 8)
+#define IMTTBCR_SL0_TWOBIT_LVL_3	(0 << 6)	/* R-Car Gen3 only */
+#define IMTTBCR_SL0_TWOBIT_LVL_2	(1 << 6)	/* R-Car Gen3 only */
+#define IMTTBCR_SL0_TWOBIT_LVL_1	(2 << 6)	/* R-Car Gen3 only */
 #define IMTTBCR_SL0_LVL_2		(0 << 4)
 #define IMTTBCR_SL0_LVL_1		(1 << 4)
 #define IMTTBCR_TSZ0_MASK		(7 << 0)
 #define IMTTBCR_TSZ0_SHIFT		O
 
-#define IMTTBCR_SL0_TWOBIT_LVL_3	(0 << 6)
-#define IMTTBCR_SL0_TWOBIT_LVL_2	(1 << 6)
-#define IMTTBCR_SL0_TWOBIT_LVL_1	(2 << 6)
-
 #define IMBUSCR				0x000c
 #define IMBUSCR_DVM			(1 << 2)
 #define IMBUSCR_BUSSEL_SYS		(0 << 0)
-- 
2.17.1

Re: [PATCH 1/2] iommu/ipmmu-vmsa: Move IMTTBCR_SL0_TWOBIT_* to restore sort order

[Simon Horman]

On Wed, Sep 04, 2019 at 02:08:01PM +0200, Geert Uytterhoeven wrote:
> Move the recently added IMTTBCR_SL0_TWOBIT_* definitions up, to make
> sure all IMTTBCR register bit definitions are sorted by decreasing bit
> index.  Add comments to make it clear that they exist on R-Car Gen3
> only.
> 
> Fixes: c295f504fb5a38ab ("iommu/ipmmu-vmsa: Allow two bit SL0")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

[PATCH 2/2] iommu/ipmmu-vmsa: Disable cache snoop transactions on R-Car Gen3

[Geert Uytterhoeven]

From: Hai Nguyen Pham <hai.pham.ud@renesas.com>

According to the Hardware Manual Errata for Rev. 1.50 of April 10, 2019,
cache snoop transactions for page table walk requests are not supported
on R-Car Gen3.

Hence, this patch removes setting these fields in the IMTTBCR register,
since it will have no effect, and adds comments to the register bit
definitions, to make it clear they apply to R-Car Gen2 only.

Signed-off-by: Hai Nguyen Pham <hai.pham.ud@renesas.com>
[geert: Reword, add comments]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
 drivers/iommu/ipmmu-vmsa.c | 71 ++++++++++++++++++++------------------
 1 file changed, 38 insertions(+), 33 deletions(-)

diff --git a/drivers/iommu/ipmmu-vmsa.c b/drivers/iommu/ipmmu-vmsa.c
index 1baabeaddc9cba1b..9da8309f71708f21 100644
--- a/drivers/iommu/ipmmu-vmsa.c
+++ b/drivers/iommu/ipmmu-vmsa.c
@@ -49,6 +49,7 @@ struct ipmmu_features {
 	bool setup_imbuscr;
 	bool twobit_imttbcr_sl0;
 	bool reserved_context;
+	bool cache_snoop;
 };
 
 struct ipmmu_vmsa_device {
@@ -115,36 +116,36 @@ static struct ipmmu_vmsa_device *to_ipmmu(struct device *dev)
 #define IMTTBCR				0x0008
 #define IMTTBCR_EAE			(1 << 31)
 #define IMTTBCR_PMB			(1 << 30)
-#define IMTTBCR_SH1_NON_SHAREABLE	(0 << 28)
-#define IMTTBCR_SH1_OUTER_SHAREABLE	(2 << 28)
-#define IMTTBCR_SH1_INNER_SHAREABLE	(3 << 28)
-#define IMTTBCR_SH1_MASK		(3 << 28)
-#define IMTTBCR_ORGN1_NC		(0 << 26)
-#define IMTTBCR_ORGN1_WB_WA		(1 << 26)
-#define IMTTBCR_ORGN1_WT		(2 << 26)
-#define IMTTBCR_ORGN1_WB		(3 << 26)
-#define IMTTBCR_ORGN1_MASK		(3 << 26)
-#define IMTTBCR_IRGN1_NC		(0 << 24)
-#define IMTTBCR_IRGN1_WB_WA		(1 << 24)
-#define IMTTBCR_IRGN1_WT		(2 << 24)
-#define IMTTBCR_IRGN1_WB		(3 << 24)
-#define IMTTBCR_IRGN1_MASK		(3 << 24)
+#define IMTTBCR_SH1_NON_SHAREABLE	(0 << 28)	/* R-Car Gen2 only */
+#define IMTTBCR_SH1_OUTER_SHAREABLE	(2 << 28)	/* R-Car Gen2 only */
+#define IMTTBCR_SH1_INNER_SHAREABLE	(3 << 28)	/* R-Car Gen2 only */
+#define IMTTBCR_SH1_MASK		(3 << 28)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN1_NC		(0 << 26)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN1_WB_WA		(1 << 26)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN1_WT		(2 << 26)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN1_WB		(3 << 26)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN1_MASK		(3 << 26)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN1_NC		(0 << 24)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN1_WB_WA		(1 << 24)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN1_WT		(2 << 24)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN1_WB		(3 << 24)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN1_MASK		(3 << 24)	/* R-Car Gen2 only */
 #define IMTTBCR_TSZ1_MASK		(7 << 16)
 #define IMTTBCR_TSZ1_SHIFT		16
-#define IMTTBCR_SH0_NON_SHAREABLE	(0 << 12)
-#define IMTTBCR_SH0_OUTER_SHAREABLE	(2 << 12)
-#define IMTTBCR_SH0_INNER_SHAREABLE	(3 << 12)
-#define IMTTBCR_SH0_MASK		(3 << 12)
-#define IMTTBCR_ORGN0_NC		(0 << 10)
-#define IMTTBCR_ORGN0_WB_WA		(1 << 10)
-#define IMTTBCR_ORGN0_WT		(2 << 10)
-#define IMTTBCR_ORGN0_WB		(3 << 10)
-#define IMTTBCR_ORGN0_MASK		(3 << 10)
-#define IMTTBCR_IRGN0_NC		(0 << 8)
-#define IMTTBCR_IRGN0_WB_WA		(1 << 8)
-#define IMTTBCR_IRGN0_WT		(2 << 8)
-#define IMTTBCR_IRGN0_WB		(3 << 8)
-#define IMTTBCR_IRGN0_MASK		(3 << 8)
+#define IMTTBCR_SH0_NON_SHAREABLE	(0 << 12)	/* R-Car Gen2 only */
+#define IMTTBCR_SH0_OUTER_SHAREABLE	(2 << 12)	/* R-Car Gen2 only */
+#define IMTTBCR_SH0_INNER_SHAREABLE	(3 << 12)	/* R-Car Gen2 only */
+#define IMTTBCR_SH0_MASK		(3 << 12)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN0_NC		(0 << 10)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN0_WB_WA		(1 << 10)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN0_WT		(2 << 10)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN0_WB		(3 << 10)	/* R-Car Gen2 only */
+#define IMTTBCR_ORGN0_MASK		(3 << 10)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN0_NC		(0 << 8)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN0_WB_WA		(1 << 8)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN0_WT		(2 << 8)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN0_WB		(3 << 8)	/* R-Car Gen2 only */
+#define IMTTBCR_IRGN0_MASK		(3 << 8)	/* R-Car Gen2 only */
 #define IMTTBCR_SL0_TWOBIT_LVL_3	(0 << 6)	/* R-Car Gen3 only */
 #define IMTTBCR_SL0_TWOBIT_LVL_2	(1 << 6)	/* R-Car Gen3 only */
 #define IMTTBCR_SL0_TWOBIT_LVL_1	(2 << 6)	/* R-Car Gen3 only */
@@ -421,17 +422,19 @@ static void ipmmu_domain_setup_context(struct ipmmu_vmsa_domain *domain)
 
 	/*
 	 * TTBCR
-	 * We use long descriptors with inner-shareable WBWA tables and allocate
-	 * the whole 32-bit VA space to TTBR0.
+	 * We use long descriptors and allocate the whole 32-bit VA space to
+	 * TTBR0.
 	 */
 	if (domain->mmu->features->twobit_imttbcr_sl0)
 		tmp = IMTTBCR_SL0_TWOBIT_LVL_1;
 	else
 		tmp = IMTTBCR_SL0_LVL_1;
 
-	ipmmu_ctx_write_root(domain, IMTTBCR, IMTTBCR_EAE |
-			     IMTTBCR_SH0_INNER_SHAREABLE | IMTTBCR_ORGN0_WB_WA |
-			     IMTTBCR_IRGN0_WB_WA | tmp);
+	if (domain->mmu->features->cache_snoop)
+		tmp |= IMTTBCR_SH0_INNER_SHAREABLE | IMTTBCR_ORGN0_WB_WA |
+		       IMTTBCR_IRGN0_WB_WA;
+
+	ipmmu_ctx_write_root(domain, IMTTBCR, IMTTBCR_EAE | tmp);
 
 	/* MAIR0 */
 	ipmmu_ctx_write_root(domain, IMMAIR0,
@@ -993,6 +996,7 @@ static const struct ipmmu_features ipmmu_features_default = {
 	.setup_imbuscr = true,
 	.twobit_imttbcr_sl0 = false,
 	.reserved_context = false,
+	.cache_snoop = true,
 };
 
 static const struct ipmmu_features ipmmu_features_rcar_gen3 = {
@@ -1003,6 +1007,7 @@ static const struct ipmmu_features ipmmu_features_rcar_gen3 = {
 	.setup_imbuscr = false,
 	.twobit_imttbcr_sl0 = true,
 	.reserved_context = true,
+	.cache_snoop = false,
 };
 
 static const struct of_device_id ipmmu_of_ids[] = {
-- 
2.17.1

Re: [PATCH 2/2] iommu/ipmmu-vmsa: Disable cache snoop transactions on R-Car Gen3

[Simon Horman]

On Wed, Sep 04, 2019 at 02:08:02PM +0200, Geert Uytterhoeven wrote:
> From: Hai Nguyen Pham <hai.pham.ud@renesas.com>
> 
> According to the Hardware Manual Errata for Rev. 1.50 of April 10, 2019,
> cache snoop transactions for page table walk requests are not supported
> on R-Car Gen3.
> 
> Hence, this patch removes setting these fields in the IMTTBCR register,
> since it will have no effect, and adds comments to the register bit
> definitions, to make it clear they apply to R-Car Gen2 only.
> 
> Signed-off-by: Hai Nguyen Pham <hai.pham.ud@renesas.com>
> [geert: Reword, add comments]
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>