[PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts

[PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts

[Geert Uytterhoeven]

	Hi all,

Recent R-Car Gen3 SoCs added an External Request Mask Register to the
System Controller (SYSC).  This register allows to mask external power
requests for CPU or 3DG domains, to prevent conflicts between powering
off CPU cores or the 3D Graphics Engine, and changing the state of
another power domain through SYSC, which could lead to CPG state machine
lock-ups.

This patch series starts making use of this register.  Note that the
register is optional, and that its location and contents are
SoC-specific.

This was inspired by a patch in the BSP by Dien Pham
<dien.pham.ry@renesas.com>.

Note that the issue fixed cannot happen in the upstream kernel, as
upstream has no support for graphics acceleration yet.  SoCs lacking the
External Request Mask Register may need a different mitigation in the
future.

Changes compared to v1[1]:
  - Improve description of cover letter and first patch.

Changes compared to RFC[2]:
  - Rebased.

This has been boot-tested on R-Car H3 ES1.0, H3 ES2.0, M3-W ES1.0, M3-N,
V3M, and E3 (only the last 3 have this register!), and regression-tested
on R-Car Gen2.

This has not been tested on R-Car H3 ES3.0, M3-W ES2.0, and V3H.

For your convenience, this series is available in the
topic/rcar3-sysc-extmask-v2 branch of my renesas-drivers git repository at
git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git.

Thanks for your comments!

[1] Not posted, but included in yesterday's renesas-drivers-2019-08-27-v5.3-rc6
[2] "[RFC PATCH 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts"
    (https://lore.kernel.org/linux-renesas-soc/20181205155028.14335-1-geert+renesas@glider.be/)
 
Geert Uytterhoeven (7):
  soc: renesas: rcar-sysc: Prepare for fixing power request conflicts
  soc: renesas: r8a7795-sysc: Fix power request conflicts
  soc: renesas: r8a7796-sysc: Fix power request conflicts
  soc: renesas: r8a77965-sysc: Fix power request conflicts
  soc: renesas: r8a77970-sysc: Fix power request conflicts
  soc: renesas: r8a77980-sysc: Fix power request conflicts
  soc: renesas: r8a77990-sysc: Fix power request conflicts

 drivers/soc/renesas/r8a7795-sysc.c  | 32 ++++++++++++++++++++++++-----
 drivers/soc/renesas/r8a7796-sysc.c  | 22 +++++++++++++++++++-
 drivers/soc/renesas/r8a77965-sysc.c |  3 +++
 drivers/soc/renesas/r8a77970-sysc.c |  3 +++
 drivers/soc/renesas/r8a77980-sysc.c |  3 +++
 drivers/soc/renesas/r8a77990-sysc.c |  3 +++
 drivers/soc/renesas/rcar-sysc.c     | 16 +++++++++++++++
 drivers/soc/renesas/rcar-sysc.h     |  7 +++++--
 8 files changed, 81 insertions(+), 8 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 v2 1/7] soc: renesas: rcar-sysc: Prepare for fixing power request conflicts

[Geert Uytterhoeven]

Recent R-Car Gen3 SoCs added an External Request Mask Register to the
System Controller (SYSC).  This register allows to mask external power
requests for CPU or 3DG domains, to prevent conflicts between powering
off CPU cores or the 3D Graphics Engine, and changing the state of
another power domain through SYSC, which could lead to CPG state machine
lock-ups.

Add support for making use of this register.  Take into account that the
register is optional, and that its location and contents are
SoC-specific.

Note that the issue fixed by this cannot happen in the upstream kernel,
as upstream has no support for graphics acceleration yet.  SoCs lacking
the External Request Mask Register may need a different mitigation in
the future.

Inspired by a patch in the BSP by Dien Pham <dien.pham.ry@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - Improve patch description.
---
 drivers/soc/renesas/rcar-sysc.c | 16 ++++++++++++++++
 drivers/soc/renesas/rcar-sysc.h |  3 +++
 2 files changed, 19 insertions(+)

diff --git a/drivers/soc/renesas/rcar-sysc.c b/drivers/soc/renesas/rcar-sysc.c
index 59b5e6b102722a6d..176de145f4230fbd 100644
--- a/drivers/soc/renesas/rcar-sysc.c
+++ b/drivers/soc/renesas/rcar-sysc.c
@@ -63,6 +63,7 @@ struct rcar_sysc_ch {
 
 static void __iomem *rcar_sysc_base;
 static DEFINE_SPINLOCK(rcar_sysc_lock); /* SMP CPUs + I/O devices */
+static u32 rcar_sysc_extmask_offs, rcar_sysc_extmask_val;
 
 static int rcar_sysc_pwr_on_off(const struct rcar_sysc_ch *sysc_ch, bool on)
 {
@@ -105,6 +106,14 @@ static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
 
 	spin_lock_irqsave(&rcar_sysc_lock, flags);
 
+	/*
+	 * Mask external power requests for CPU or 3DG domains
+	 */
+	if (rcar_sysc_extmask_val) {
+		iowrite32(rcar_sysc_extmask_val,
+			  rcar_sysc_base + rcar_sysc_extmask_offs);
+	}
+
 	/*
 	 * The interrupt source needs to be enabled, but masked, to prevent the
 	 * CPU from receiving it.
@@ -148,6 +157,9 @@ static int rcar_sysc_power(const struct rcar_sysc_ch *sysc_ch, bool on)
 	iowrite32(isr_mask, rcar_sysc_base + SYSCISCR);
 
  out:
+	if (rcar_sysc_extmask_val)
+		iowrite32(0, rcar_sysc_base + rcar_sysc_extmask_offs);
+
 	spin_unlock_irqrestore(&rcar_sysc_lock, flags);
 
 	pr_debug("sysc power %s domain %d: %08x -> %d\n", on ? "on" : "off",
@@ -360,6 +372,10 @@ static int __init rcar_sysc_pd_init(void)
 
 	rcar_sysc_base = base;
 
+	/* Optional External Request Mask Register */
+	rcar_sysc_extmask_offs = info->extmask_offs;
+	rcar_sysc_extmask_val = info->extmask_val;
+
 	domains = kzalloc(sizeof(*domains), GFP_KERNEL);
 	if (!domains) {
 		error = -ENOMEM;
diff --git a/drivers/soc/renesas/rcar-sysc.h b/drivers/soc/renesas/rcar-sysc.h
index 485520a5b295c13e..21ee3ff8620bbafe 100644
--- a/drivers/soc/renesas/rcar-sysc.h
+++ b/drivers/soc/renesas/rcar-sysc.h
@@ -44,6 +44,9 @@ struct rcar_sysc_info {
 	int (*init)(void);	/* Optional */
 	const struct rcar_sysc_area *areas;
 	unsigned int num_areas;
+	/* Optional External Request Mask Register */
+	u32 extmask_offs;	/* SYSCEXTMASK register offset */
+	u32 extmask_val;	/* SYSCEXTMASK register mask value */
 };
 
 extern const struct rcar_sysc_info r8a7743_sysc_info;
-- 
2.17.1

[PATCH v2 2/7] soc: renesas: r8a7795-sysc: Fix power request conflicts

[Geert Uytterhoeven]

Describe the location and contents of the SYSCEXTMASK register on R-Car
H3, to prevent conflicts between internal and external power requests.

This register does not exist on R-Car H3 ES1.x and ES2.x.

Based on a patch in the BSP by Dien Pham <dien.pham.ry@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - No changes.
---
 drivers/soc/renesas/r8a7795-sysc.c | 32 +++++++++++++++++++++++++-----
 drivers/soc/renesas/rcar-sysc.h    |  2 +-
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/drivers/soc/renesas/r8a7795-sysc.c b/drivers/soc/renesas/r8a7795-sysc.c
index cda27a67de9876af..7e15cd09c4eb4780 100644
--- a/drivers/soc/renesas/r8a7795-sysc.c
+++ b/drivers/soc/renesas/r8a7795-sysc.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2016-2017 Glider bvba
  */
 
+#include <linux/bits.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
 #include <linux/sys_soc.h>
@@ -51,25 +52,46 @@ static struct rcar_sysc_area r8a7795_areas[] __initdata = {
 
 
 	/*
-	 * Fixups for R-Car H3 revisions after ES1.x
+	 * Fixups for R-Car H3 revisions
 	 */
 
-static const struct soc_device_attribute r8a7795es1[] __initconst = {
-	{ .soc_id = "r8a7795", .revision = "ES1.*" },
+#define HAS_A2VC0	BIT(0)		/* Power domain A2VC0 is present */
+#define NO_EXTMASK	BIT(1)		/* Missing SYSCEXTMASK register */
+
+static const struct soc_device_attribute r8a7795_quirks_match[] __initconst = {
+	{
+		.soc_id = "r8a7795", .revision = "ES1.*",
+		.data = (void *)(HAS_A2VC0 | NO_EXTMASK),
+	}, {
+		.soc_id = "r8a7795", .revision = "ES2.*",
+		.data = (void *)(NO_EXTMASK),
+	},
 	{ /* sentinel */ }
 };
 
 static int __init r8a7795_sysc_init(void)
 {
-	if (!soc_device_match(r8a7795es1))
+	const struct soc_device_attribute *attr;
+	u32 quirks = 0;
+
+	attr = soc_device_match(r8a7795_quirks_match);
+	if (attr)
+		quirks = (uintptr_t)attr->data;
+
+	if (!(quirks & HAS_A2VC0))
 		rcar_sysc_nullify(r8a7795_areas, ARRAY_SIZE(r8a7795_areas),
 				  R8A7795_PD_A2VC0);
 
+	if (quirks & NO_EXTMASK)
+		r8a7795_sysc_info.extmask_val = 0;
+
 	return 0;
 }
 
-const struct rcar_sysc_info r8a7795_sysc_info __initconst = {
+struct rcar_sysc_info r8a7795_sysc_info __initdata = {
 	.init = r8a7795_sysc_init,
 	.areas = r8a7795_areas,
 	.num_areas = ARRAY_SIZE(r8a7795_areas),
+	.extmask_offs = 0x2f8,
+	.extmask_val = BIT(0),
 };
diff --git a/drivers/soc/renesas/rcar-sysc.h b/drivers/soc/renesas/rcar-sysc.h
index 21ee3ff8620bbafe..499797a9e18c2f10 100644
--- a/drivers/soc/renesas/rcar-sysc.h
+++ b/drivers/soc/renesas/rcar-sysc.h
@@ -59,7 +59,7 @@ extern const struct rcar_sysc_info r8a7790_sysc_info;
 extern const struct rcar_sysc_info r8a7791_sysc_info;
 extern const struct rcar_sysc_info r8a7792_sysc_info;
 extern const struct rcar_sysc_info r8a7794_sysc_info;
-extern const struct rcar_sysc_info r8a7795_sysc_info;
+extern struct rcar_sysc_info r8a7795_sysc_info;
 extern const struct rcar_sysc_info r8a7796_sysc_info;
 extern const struct rcar_sysc_info r8a77965_sysc_info;
 extern const struct rcar_sysc_info r8a77970_sysc_info;
-- 
2.17.1

[PATCH v2 3/7] soc: renesas: r8a7796-sysc: Fix power request conflicts

[Geert Uytterhoeven]

Describe the location and contents of the SYSCEXTMASK register on R-Car
M3-W, to prevent conflicts between internal and external power requests.

This register does not exist on R-Car M3-W ES1.x.

Based on a patch in the BSP by Dien Pham <dien.pham.ry@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - No changes.
---
 drivers/soc/renesas/r8a7796-sysc.c | 22 +++++++++++++++++++++-
 drivers/soc/renesas/rcar-sysc.h    |  2 +-
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/renesas/r8a7796-sysc.c b/drivers/soc/renesas/r8a7796-sysc.c
index 1b06f868b6e81c79..a4eaa8d1f5d0f49d 100644
--- a/drivers/soc/renesas/r8a7796-sysc.c
+++ b/drivers/soc/renesas/r8a7796-sysc.c
@@ -5,8 +5,10 @@
  * Copyright (C) 2016 Glider bvba
  */
 
+#include <linux/bits.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
+#include <linux/sys_soc.h>
 
 #include <dt-bindings/power/r8a7796-sysc.h>
 
@@ -39,7 +41,25 @@ static const struct rcar_sysc_area r8a7796_areas[] __initconst = {
 	{ "a3ir",	0x180, 0, R8A7796_PD_A3IR,	R8A7796_PD_ALWAYS_ON },
 };
 
-const struct rcar_sysc_info r8a7796_sysc_info __initconst = {
+
+/* Fixups for R-Car M3-W ES1.x revision */
+static const struct soc_device_attribute r8a7796es1[] __initconst = {
+	{ .soc_id = "r8a7796", .revision = "ES1.*" },
+	{ /* sentinel */ }
+};
+
+static int __init r8a7796_sysc_init(void)
+{
+	if (soc_device_match(r8a7796es1))
+		r8a7796_sysc_info.extmask_val = 0;
+
+	return 0;
+}
+
+struct rcar_sysc_info r8a7796_sysc_info __initdata = {
+	.init = r8a7796_sysc_init,
 	.areas = r8a7796_areas,
 	.num_areas = ARRAY_SIZE(r8a7796_areas),
+	.extmask_offs = 0x2f8,
+	.extmask_val = BIT(0),
 };
diff --git a/drivers/soc/renesas/rcar-sysc.h b/drivers/soc/renesas/rcar-sysc.h
index 499797a9e18c2f10..64c2a0fa7945d80b 100644
--- a/drivers/soc/renesas/rcar-sysc.h
+++ b/drivers/soc/renesas/rcar-sysc.h
@@ -60,7 +60,7 @@ extern const struct rcar_sysc_info r8a7791_sysc_info;
 extern const struct rcar_sysc_info r8a7792_sysc_info;
 extern const struct rcar_sysc_info r8a7794_sysc_info;
 extern struct rcar_sysc_info r8a7795_sysc_info;
-extern const struct rcar_sysc_info r8a7796_sysc_info;
+extern struct rcar_sysc_info r8a7796_sysc_info;
 extern const struct rcar_sysc_info r8a77965_sysc_info;
 extern const struct rcar_sysc_info r8a77970_sysc_info;
 extern const struct rcar_sysc_info r8a77980_sysc_info;
-- 
2.17.1

[PATCH v2 4/7] soc: renesas: r8a77965-sysc: Fix power request conflicts

[Geert Uytterhoeven]

Describe the location and contents of the SYSCEXTMASK register on R-Car
M3-N, to prevent conflicts between internal and external power requests.

Based on a patch in the BSP by Dien Pham <dien.pham.ry@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - No changes.
---
 drivers/soc/renesas/r8a77965-sysc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/soc/renesas/r8a77965-sysc.c b/drivers/soc/renesas/r8a77965-sysc.c
index e0533beb50fd7063..b5d8230d4bbc1b87 100644
--- a/drivers/soc/renesas/r8a77965-sysc.c
+++ b/drivers/soc/renesas/r8a77965-sysc.c
@@ -7,6 +7,7 @@
  * Copyright (C) 2016 Glider bvba
  */
 
+#include <linux/bits.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
 
@@ -33,4 +34,6 @@ static const struct rcar_sysc_area r8a77965_areas[] __initconst = {
 const struct rcar_sysc_info r8a77965_sysc_info __initconst = {
 	.areas = r8a77965_areas,
 	.num_areas = ARRAY_SIZE(r8a77965_areas),
+	.extmask_offs = 0x2f8,
+	.extmask_val = BIT(0),
 };
-- 
2.17.1

[PATCH v2 5/7] soc: renesas: r8a77970-sysc: Fix power request conflicts

[Geert Uytterhoeven]

Describe the location and contents of the SYSCEXTMASK register on R-Car
V3M, to prevent conflicts between internal and external power requests.

Based on a patch in the BSP by Dien Pham <dien.pham.ry@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - No changes.
---
 drivers/soc/renesas/r8a77970-sysc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/soc/renesas/r8a77970-sysc.c b/drivers/soc/renesas/r8a77970-sysc.c
index 280c48b80f240424..b3033e3f0fd0b0ff 100644
--- a/drivers/soc/renesas/r8a77970-sysc.c
+++ b/drivers/soc/renesas/r8a77970-sysc.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2017 Cogent Embedded Inc.
  */
 
+#include <linux/bits.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
 
@@ -32,4 +33,6 @@ static const struct rcar_sysc_area r8a77970_areas[] __initconst = {
 const struct rcar_sysc_info r8a77970_sysc_info __initconst = {
 	.areas = r8a77970_areas,
 	.num_areas = ARRAY_SIZE(r8a77970_areas),
+	.extmask_offs = 0x1b0,
+	.extmask_val = BIT(0),
 };
-- 
2.17.1

[PATCH v2 6/7] soc: renesas: r8a77980-sysc: Fix power request conflicts

[Geert Uytterhoeven]

Describe the location and contents of the SYSCEXTMASK register on R-Car
V3H, to prevent conflicts between internal and external power requests.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - No changes.
---
 drivers/soc/renesas/r8a77980-sysc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/soc/renesas/r8a77980-sysc.c b/drivers/soc/renesas/r8a77980-sysc.c
index a8dbe55e8ba82d7e..e3b5ee1b3091dee1 100644
--- a/drivers/soc/renesas/r8a77980-sysc.c
+++ b/drivers/soc/renesas/r8a77980-sysc.c
@@ -6,6 +6,7 @@
  * Copyright (C) 2018 Cogent Embedded, Inc.
  */
 
+#include <linux/bits.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
 
@@ -49,4 +50,6 @@ static const struct rcar_sysc_area r8a77980_areas[] __initconst = {
 const struct rcar_sysc_info r8a77980_sysc_info __initconst = {
 	.areas = r8a77980_areas,
 	.num_areas = ARRAY_SIZE(r8a77980_areas),
+	.extmask_offs = 0x138,
+	.extmask_val = BIT(0),
 };
-- 
2.17.1

[PATCH v2 7/7] soc: renesas: r8a77990-sysc: Fix power request conflicts

[Geert Uytterhoeven]

Describe the location and contents of the SYSCEXTMASK register on R-Car
E3, to prevent conflicts between internal and external power requests.

Based on a patch in the BSP by Dien Pham <dien.pham.ry@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v2:
  - No changes.
---
 drivers/soc/renesas/r8a77990-sysc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/soc/renesas/r8a77990-sysc.c b/drivers/soc/renesas/r8a77990-sysc.c
index 664b244eb1dd9d95..1d2432020b7a15d2 100644
--- a/drivers/soc/renesas/r8a77990-sysc.c
+++ b/drivers/soc/renesas/r8a77990-sysc.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2018 Renesas Electronics Corp.
  */
 
+#include <linux/bits.h>
 #include <linux/bug.h>
 #include <linux/kernel.h>
 #include <linux/sys_soc.h>
@@ -50,4 +51,6 @@ const struct rcar_sysc_info r8a77990_sysc_info __initconst = {
 	.init = r8a77990_sysc_init,
 	.areas = r8a77990_areas,
 	.num_areas = ARRAY_SIZE(r8a77990_areas),
+	.extmask_offs = 0x2f8,
+	.extmask_val = BIT(0),
 };
-- 
2.17.1

RE: [PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts

[Yoshihiro Shimoda]

Hi Geert-san,

> From: Geert Uytterhoeven, Sent: Wednesday, August 28, 2019 8:36 PM
> 
> 	Hi all,
> 
> Recent R-Car Gen3 SoCs added an External Request Mask Register to the
> System Controller (SYSC).  This register allows to mask external power
> requests for CPU or 3DG domains, to prevent conflicts between powering
> off CPU cores or the 3D Graphics Engine, and changing the state of
> another power domain through SYSC, which could lead to CPG state machine
> lock-ups.
> 
> This patch series starts making use of this register.  Note that the
> register is optional, and that its location and contents are
> SoC-specific.
> 
> This was inspired by a patch in the BSP by Dien Pham
> <dien.pham.ry@renesas.com>.
> 
> Note that the issue fixed cannot happen in the upstream kernel, as
> upstream has no support for graphics acceleration yet.  SoCs lacking the
> External Request Mask Register may need a different mitigation in the
> future.
> 
> Changes compared to v1[1]:
>   - Improve description of cover letter and first patch.
> 
> Changes compared to RFC[2]:
>   - Rebased.
> 
> This has been boot-tested on R-Car H3 ES1.0, H3 ES2.0, M3-W ES1.0, M3-N,
> V3M, and E3 (only the last 3 have this register!), and regression-tested
> on R-Car Gen2.
> 
> This has not been tested on R-Car H3 ES3.0, M3-W ES2.0, and V3H.

I also boot-tested on R-Car H3 ES3.0 and M3-W ES3.0.
And I reviewed all patches, so:

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Best regards,
Yoshihiro Shimoda

Re: [PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts

[Simon Horman]

On Wed, Aug 28, 2019 at 01:36:11PM +0200, Geert Uytterhoeven wrote:
> 	Hi all,
> 
> Recent R-Car Gen3 SoCs added an External Request Mask Register to the
> System Controller (SYSC).  This register allows to mask external power
> requests for CPU or 3DG domains, to prevent conflicts between powering
> off CPU cores or the 3D Graphics Engine, and changing the state of
> another power domain through SYSC, which could lead to CPG state machine
> lock-ups.
> 
> This patch series starts making use of this register.  Note that the
> register is optional, and that its location and contents are
> SoC-specific.
> 
> This was inspired by a patch in the BSP by Dien Pham
> <dien.pham.ry@renesas.com>.
> 
> Note that the issue fixed cannot happen in the upstream kernel, as
> upstream has no support for graphics acceleration yet.  SoCs lacking the
> External Request Mask Register may need a different mitigation in the
> future.
> 
> Changes compared to v1[1]:
>   - Improve description of cover letter and first patch.
> 
> Changes compared to RFC[2]:
>   - Rebased.
> 
> This has been boot-tested on R-Car H3 ES1.0, H3 ES2.0, M3-W ES1.0, M3-N,
> V3M, and E3 (only the last 3 have this register!), and regression-tested
> on R-Car Gen2.
> 
> This has not been tested on R-Car H3 ES3.0, M3-W ES2.0, and V3H.
> 
> For your convenience, this series is available in the
> topic/rcar3-sysc-extmask-v2 branch of my renesas-drivers git repository at
> git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git.
> 
> Thanks for your comments!

Looks good to me.

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

Re: [PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts

[Geert Uytterhoeven]

On Thu, Aug 29, 2019 at 6:14 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@renesas.com> wrote:
> > From: Geert Uytterhoeven, Sent: Wednesday, August 28, 2019 8:36 PM
> > Recent R-Car Gen3 SoCs added an External Request Mask Register to the
> > System Controller (SYSC).  This register allows to mask external power
> > requests for CPU or 3DG domains, to prevent conflicts between powering
> > off CPU cores or the 3D Graphics Engine, and changing the state of
> > another power domain through SYSC, which could lead to CPG state machine
> > lock-ups.
> >
> > This patch series starts making use of this register.  Note that the
> > register is optional, and that its location and contents are
> > SoC-specific.
> >
> > This was inspired by a patch in the BSP by Dien Pham
> > <dien.pham.ry@renesas.com>.
> >
> > Note that the issue fixed cannot happen in the upstream kernel, as
> > upstream has no support for graphics acceleration yet.  SoCs lacking the
> > External Request Mask Register may need a different mitigation in the
> > future.
> >
> > Changes compared to v1[1]:
> >   - Improve description of cover letter and first patch.
> >
> > Changes compared to RFC[2]:
> >   - Rebased.
> >
> > This has been boot-tested on R-Car H3 ES1.0, H3 ES2.0, M3-W ES1.0, M3-N,
> > V3M, and E3 (only the last 3 have this register!), and regression-tested
> > on R-Car Gen2.
> >
> > This has not been tested on R-Car H3 ES3.0, M3-W ES2.0, and V3H.
>
> I also boot-tested on R-Car H3 ES3.0 and M3-W ES3.0.
> And I reviewed all patches, so:
>
> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Thanks, queued in renesas-devel for v5.5.


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