LinuxLists.cc - [PATCH v2 0/4] soc: samsung: exynos-chipid and asv improvements

2020-12-07 19:07:56

Subject: [PATCH v2 0/4] soc: samsung: exynos-chipid and asv improvements

Hi,

Changes since v1:
1. Drop patch "soc: samsung: exynos-chipid: initialize later - with
arch_initcall" which is now superseded by convertin to a driver.
2. Include Marek's patch, just for the reference and rebase.
3. Add patch "soc: samsung: exynos-asv: handle reading revision register
error".
4. Add patch "soc: samsung: exynos-chipid: convert to driver and merge
exynos-asv".

Best regards,
Krzysztof

Krzysztof Kozlowski (3):
soc: samsung: exynos-asv: handle reading revision register error
soc: samsung: exynos-chipid: order list of SoCs by name
soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

Marek Szyprowski (1):
soc: samsung: exynos-asv: don't defer early on not-supported SoCs

arch/arm/mach-exynos/Kconfig | 1 -
drivers/soc/samsung/Kconfig | 12 ++---
drivers/soc/samsung/Makefile | 3 +-
drivers/soc/samsung/exynos-asv.c | 57 ++++++++-------------
drivers/soc/samsung/exynos-asv.h | 2 +
drivers/soc/samsung/exynos-chipid.c | 78 ++++++++++++++++++++---------
6 files changed, 81 insertions(+), 72 deletions(-)

--
2.25.1

2020-12-07 19:09:23

by Krzysztof Kozlowski

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Subject: [PATCH v2 1/4] soc: samsung: exynos-asv: don't defer early on not-supported SoCs

From: Marek Szyprowski <[email protected]>

Check if the SoC is really supported before gathering the needed
resources. This fixes endless deferred probe on some SoCs other than
Exynos5422 (like Exynos5410).

Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Cc: <[email protected]>
Signed-off-by: Marek Szyprowski <[email protected]>
Signed-off-by: Krzysztof Kozlowski <[email protected]>
---
drivers/soc/samsung/exynos-asv.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index 8abf4dfaa5c5..f653e3533f0f 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -119,11 +119,6 @@ static int exynos_asv_probe(struct platform_device *pdev)
u32 product_id = 0;
int ret, i;

- cpu_dev = get_cpu_device(0);
- ret = dev_pm_opp_get_opp_count(cpu_dev);
- if (ret < 0)
- return -EPROBE_DEFER;
-
asv = devm_kzalloc(&pdev->dev, sizeof(*asv), GFP_KERNEL);
if (!asv)
return -ENOMEM;
@@ -144,6 +139,11 @@ static int exynos_asv_probe(struct platform_device *pdev)
return -ENODEV;
}

+ cpu_dev = get_cpu_device(0);
+ ret = dev_pm_opp_get_opp_count(cpu_dev);
+ if (ret < 0)
+ return -EPROBE_DEFER;
+
ret = of_property_read_u32(pdev->dev.of_node, "samsung,asv-bin",
&asv->of_bin);
if (ret < 0)
--
2.25.1

2020-12-07 19:10:05

by Krzysztof Kozlowski

[permalink] [raw]

Subject: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision register error

If regmap_read() fails, the product_id local variable will contain
random value from the stack. Do not try to parse such value and fail
the ASV driver probe.

Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Cc: <[email protected]>
Signed-off-by: Krzysztof Kozlowski <[email protected]>
---
drivers/soc/samsung/exynos-asv.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index f653e3533f0f..5daeadc36382 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -129,7 +129,13 @@ static int exynos_asv_probe(struct platform_device *pdev)
return PTR_ERR(asv->chipid_regmap);
}

- regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID, &product_id);
+ ret = regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID,
+ &product_id);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Cannot read revision from ChipID: %d\n",
+ ret);
+ return -ENODEV;
+ }

switch (product_id & EXYNOS_MASK) {
case 0xE5422000:
--
2.25.1

2020-12-07 19:10:32

by Krzysztof Kozlowski

[permalink] [raw]

Subject: [PATCH v2 3/4] soc: samsung: exynos-chipid: order list of SoCs by name

Bring some order to the list of SoCs. No functional change.

Signed-off-by: Krzysztof Kozlowski <[email protected]>
---
drivers/soc/samsung/exynos-chipid.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
index 8d4d05086906..b4cd0cc00f45 100644
--- a/drivers/soc/samsung/exynos-chipid.c
+++ b/drivers/soc/samsung/exynos-chipid.c
@@ -20,6 +20,7 @@ static const struct exynos_soc_id {
const char *name;
unsigned int id;
} soc_ids[] = {
+ /* List ordered by SoC name */
{ "EXYNOS3250", 0xE3472000 },
{ "EXYNOS4210", 0x43200000 }, /* EVT0 revision */
{ "EXYNOS4210", 0x43210000 },
@@ -29,10 +30,10 @@ static const struct exynos_soc_id {
{ "EXYNOS5260", 0xE5260000 },
{ "EXYNOS5410", 0xE5410000 },
{ "EXYNOS5420", 0xE5420000 },
+ { "EXYNOS5433", 0xE5433000 },
{ "EXYNOS5440", 0xE5440000 },
{ "EXYNOS5800", 0xE5422000 },
{ "EXYNOS7420", 0xE7420000 },
- { "EXYNOS5433", 0xE5433000 },
};

static const char * __init product_id_to_soc_id(unsigned int product_id)
--
2.25.1

2020-12-07 19:10:42

by Krzysztof Kozlowski

[permalink] [raw]

Subject: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

The Exynos Chip ID driver on Exynos SoCs has so far only informational
purpose - to expose the SoC device in sysfs. No other drivers depend on
it so there is really no benefit of initializing it early.

The code would be the most flexible if converted to a regular driver.
However there is already another driver - Exynos ASV (Adaptive Supply
Voltage) - which binds to the device node of Chip ID.

The solution is to convert the Exynos Chip ID to a built in driver and
merge the Exynos ASV into it.

This has several benefits:
1. Although the Exynos ASV driver binds to a device node present in all
Exynos DTS (generic compatible), it fails to probe except on the
supported ones (only Exynos5422). This means that the regular boot
process has a planned/expected device probe failure.

Merging the ASV into Chip ID will remove this probe failure because
the final driver will always bind, just with disabled ASV features.

2. Allows to use dev_info() as the SoC bus is present (since
core_initcall).

3. Could speed things up because of execution of Chip ID code in a SMP
environment (after bringing up secondary CPUs, unlike early_initcall),
This reduces the amount of work to be done early, when the kernel has
to bring up critical devices.

5. Makes the Chip ID code defer-probe friendly,

Signed-off-by: Krzysztof Kozlowski <[email protected]>
---
arch/arm/mach-exynos/Kconfig | 1 -
drivers/soc/samsung/Kconfig | 12 ++---
drivers/soc/samsung/Makefile | 3 +-
drivers/soc/samsung/exynos-asv.c | 45 +++++------------
drivers/soc/samsung/exynos-asv.h | 2 +
drivers/soc/samsung/exynos-chipid.c | 75 ++++++++++++++++++++---------
6 files changed, 70 insertions(+), 68 deletions(-)

diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 56d272967fc0..5a48abac6af4 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -13,7 +13,6 @@ menuconfig ARCH_EXYNOS
select ARM_GIC
select EXYNOS_IRQ_COMBINER
select COMMON_CLK_SAMSUNG
- select EXYNOS_ASV
select EXYNOS_CHIPID
select EXYNOS_THERMAL
select EXYNOS_PMU
diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
index fc7f48a92288..5745d7e5908e 100644
--- a/drivers/soc/samsung/Kconfig
+++ b/drivers/soc/samsung/Kconfig
@@ -7,21 +7,19 @@ menuconfig SOC_SAMSUNG

if SOC_SAMSUNG

-config EXYNOS_ASV
- bool "Exynos Adaptive Supply Voltage support" if COMPILE_TEST
- depends on (ARCH_EXYNOS && EXYNOS_CHIPID) || COMPILE_TEST
- select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
-
# There is no need to enable these drivers for ARMv8
config EXYNOS_ASV_ARM
bool "Exynos ASV ARMv7-specific driver extensions" if COMPILE_TEST
- depends on EXYNOS_ASV
+ depends on EXYNOS_CHIPID

config EXYNOS_CHIPID
- bool "Exynos Chipid controller driver" if COMPILE_TEST
+ bool "Exynos ChipID controller and ASV driver" if COMPILE_TEST
depends on ARCH_EXYNOS || COMPILE_TEST
+ select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
select MFD_SYSCON
select SOC_BUS
+ help
+ Support for Samsung Exynos SoC ChipID and Adaptive Supply Voltage.

config EXYNOS_PMU
bool "Exynos PMU controller driver" if COMPILE_TEST
diff --git a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile
index 59e8e9453f27..0c523a8de4eb 100644
--- a/drivers/soc/samsung/Makefile
+++ b/drivers/soc/samsung/Makefile
@@ -1,9 +1,8 @@
# SPDX-License-Identifier: GPL-2.0

-obj-$(CONFIG_EXYNOS_ASV) += exynos-asv.o
obj-$(CONFIG_EXYNOS_ASV_ARM) += exynos5422-asv.o

-obj-$(CONFIG_EXYNOS_CHIPID) += exynos-chipid.o
+obj-$(CONFIG_EXYNOS_CHIPID) += exynos-chipid.o exynos-asv.o
obj-$(CONFIG_EXYNOS_PMU) += exynos-pmu.o

obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS) += exynos3250-pmu.o exynos4-pmu.o \
diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index 5daeadc36382..d60af8acc391 100644
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -2,7 +2,9 @@
/*
* Copyright (c) 2019 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
+ * Copyright (c) 2020 Krzysztof Kozlowski <[email protected]>
* Author: Sylwester Nawrocki <[email protected]>
+ * Author: Krzysztof Kozlowski <[email protected]>
*
* Samsung Exynos SoC Adaptive Supply Voltage support
*/
@@ -10,12 +12,7 @@
#include <linux/cpu.h>
#include <linux/device.h>
#include <linux/errno.h>
-#include <linux/init.h>
-#include <linux/mfd/syscon.h>
-#include <linux/module.h>
#include <linux/of.h>
-#include <linux/of_device.h>
-#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/regmap.h>
#include <linux/soc/samsung/exynos-chipid.h>
@@ -111,7 +108,7 @@ static int exynos_asv_update_opps(struct exynos_asv *asv)
return 0;
}

-static int exynos_asv_probe(struct platform_device *pdev)
+int exynos_asv_init(struct device *dev, struct regmap *regmap)
{
int (*probe_func)(struct exynos_asv *asv);
struct exynos_asv *asv;
@@ -119,21 +116,16 @@ static int exynos_asv_probe(struct platform_device *pdev)
u32 product_id = 0;
int ret, i;

- asv = devm_kzalloc(&pdev->dev, sizeof(*asv), GFP_KERNEL);
+ asv = devm_kzalloc(dev, sizeof(*asv), GFP_KERNEL);
if (!asv)
return -ENOMEM;

- asv->chipid_regmap = device_node_to_regmap(pdev->dev.of_node);
- if (IS_ERR(asv->chipid_regmap)) {
- dev_err(&pdev->dev, "Could not find syscon regmap\n");
- return PTR_ERR(asv->chipid_regmap);
- }
-
+ asv->chipid_regmap = regmap;
+ asv->dev = dev;
ret = regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID,
&product_id);
if (ret < 0) {
- dev_err(&pdev->dev, "Cannot read revision from ChipID: %d\n",
- ret);
+ dev_err(dev, "Cannot read revision from ChipID: %d\n", ret);
return -ENODEV;
}

@@ -142,7 +134,9 @@ static int exynos_asv_probe(struct platform_device *pdev)
probe_func = exynos5422_asv_init;
break;
default:
- return -ENODEV;
+ dev_dbg(dev, "No ASV support for this SoC\n");
+ devm_kfree(dev, asv);
+ return 0;
}

cpu_dev = get_cpu_device(0);
@@ -150,14 +144,11 @@ static int exynos_asv_probe(struct platform_device *pdev)
if (ret < 0)
return -EPROBE_DEFER;

- ret = of_property_read_u32(pdev->dev.of_node, "samsung,asv-bin",
+ ret = of_property_read_u32(dev->of_node, "samsung,asv-bin",
&asv->of_bin);
if (ret < 0)
asv->of_bin = -EINVAL;

- asv->dev = &pdev->dev;
- dev_set_drvdata(&pdev->dev, asv);
-
for (i = 0; i < ARRAY_SIZE(asv->subsys); i++)
asv->subsys[i].asv = asv;

@@ -167,17 +158,3 @@ static int exynos_asv_probe(struct platform_device *pdev)

return exynos_asv_update_opps(asv);
}
-
-static const struct of_device_id exynos_asv_of_device_ids[] = {
- { .compatible = "samsung,exynos4210-chipid" },
- {}
-};
-
-static struct platform_driver exynos_asv_driver = {
- .driver = {
- .name = "exynos-asv",
- .of_match_table = exynos_asv_of_device_ids,
- },
- .probe = exynos_asv_probe,
-};
-module_platform_driver(exynos_asv_driver);
diff --git a/drivers/soc/samsung/exynos-asv.h b/drivers/soc/samsung/exynos-asv.h
index 3fd1f2acd999..dcbe154db31e 100644
--- a/drivers/soc/samsung/exynos-asv.h
+++ b/drivers/soc/samsung/exynos-asv.h
@@ -68,4 +68,6 @@ static inline u32 exynos_asv_opp_get_frequency(const struct exynos_asv_subsys *s
return __asv_get_table_entry(&subsys->table, level, 0);
}

+int exynos_asv_init(struct device *dev, struct regmap *regmap);
+
#endif /* __LINUX_SOC_EXYNOS_ASV_H */
diff --git a/drivers/soc/samsung/exynos-chipid.c b/drivers/soc/samsung/exynos-chipid.c
index b4cd0cc00f45..fa6a9b9f6d70 100644
--- a/drivers/soc/samsung/exynos-chipid.c
+++ b/drivers/soc/samsung/exynos-chipid.c
@@ -2,20 +2,28 @@
/*
* Copyright (c) 2019 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
+ * Copyright (c) 2020 Krzysztof Kozlowski <[email protected]>
*
* Exynos - CHIP ID support
* Author: Pankaj Dubey <[email protected]>
* Author: Bartlomiej Zolnierkiewicz <[email protected]>
+ * Author: Krzysztof Kozlowski <[email protected]>
+ *
+ * Samsung Exynos SoC Adaptive Supply Voltage and Chip ID support
*/

-#include <linux/io.h>
+#include <linux/device.h>
+#include <linux/errno.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
+#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/soc/samsung/exynos-chipid.h>
#include <linux/sys_soc.h>

+#include "exynos-asv.h"
+
static const struct exynos_soc_id {
const char *name;
unsigned int id;
@@ -46,25 +54,17 @@ static const char * __init product_id_to_soc_id(unsigned int product_id)
return NULL;
}

-static int __init exynos_chipid_early_init(void)
+static int exynos_chipid_probe(struct platform_device *pdev)
{
struct soc_device_attribute *soc_dev_attr;
struct soc_device *soc_dev;
struct device_node *root;
- struct device_node *syscon;
struct regmap *regmap;
u32 product_id;
u32 revision;
int ret;

- syscon = of_find_compatible_node(NULL, NULL,
- "samsung,exynos4210-chipid");
- if (!syscon)
- return -ENODEV;
-
- regmap = device_node_to_regmap(syscon);
- of_node_put(syscon);
-
+ regmap = device_node_to_regmap(pdev->dev.of_node);
if (IS_ERR(regmap))
return PTR_ERR(regmap);

@@ -74,7 +74,8 @@ static int __init exynos_chipid_early_init(void)

revision = product_id & EXYNOS_REV_MASK;

- soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
+ soc_dev_attr = devm_kzalloc(&pdev->dev, sizeof(*soc_dev_attr),
+ GFP_KERNEL);
if (!soc_dev_attr)
return -ENOMEM;

@@ -84,31 +85,57 @@ static int __init exynos_chipid_early_init(void)
of_property_read_string(root, "model", &soc_dev_attr->machine);
of_node_put(root);

- soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%x", revision);
+ soc_dev_attr->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL,
+ "%x", revision);
soc_dev_attr->soc_id = product_id_to_soc_id(product_id);
if (!soc_dev_attr->soc_id) {
pr_err("Unknown SoC\n");
- ret = -ENODEV;
- goto err;
+ return -ENODEV;
}

/* please note that the actual registration will be deferred */
soc_dev = soc_device_register(soc_dev_attr);
- if (IS_ERR(soc_dev)) {
- ret = PTR_ERR(soc_dev);
+ if (IS_ERR(soc_dev))
+ return PTR_ERR(soc_dev);
+
+ ret = exynos_asv_init(&pdev->dev, regmap);
+ if (ret)
goto err;
- }

- /* it is too early to use dev_info() here (soc_dev is NULL) */
- pr_info("soc soc0: Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x] Detected\n",
- soc_dev_attr->soc_id, product_id, revision);
+ platform_set_drvdata(pdev, soc_dev);
+
+ dev_info(soc_device_to_device(soc_dev),
+ "Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x] Detected\n",
+ soc_dev_attr->soc_id, product_id, revision);

return 0;

err:
- kfree(soc_dev_attr->revision);
- kfree(soc_dev_attr);
+ soc_device_unregister(soc_dev);
+
return ret;
}

-early_initcall(exynos_chipid_early_init);
+static int exynos_chipid_remove(struct platform_device *pdev)
+{
+ struct soc_device *soc_dev = platform_get_drvdata(pdev);
+
+ soc_device_unregister(soc_dev);
+
+ return 0;
+}
+
+static const struct of_device_id exynos_chipid_of_device_ids[] = {
+ { .compatible = "samsung,exynos4210-chipid" },
+ {}
+};
+
+static struct platform_driver exynos_chipid_driver = {
+ .driver = {
+ .name = "exynos-chipid",
+ .of_match_table = exynos_chipid_of_device_ids,
+ },
+ .probe = exynos_chipid_probe,
+ .remove = exynos_chipid_remove,
+};
+builtin_platform_driver(exynos_chipid_driver);
--
2.25.1

2020-12-08 06:25:59

by Pankaj Dubey

[permalink] [raw]

Subject: RE: [PATCH v2 1/4] soc: samsung: exynos-asv: don't defer early on not-supported SoCs

2020-12-08 06:29:31

by Pankaj Dubey

[permalink] [raw]

Subject: RE: [PATCH v2 3/4] soc: samsung: exynos-chipid: order list of SoCs by name

2020-12-08 07:08:52

by Pankaj Dubey

[permalink] [raw]

Subject: RE: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision register error

2020-12-08 08:51:15

by Krzysztof Kozlowski

[permalink] [raw]

Subject: Re: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

On Tue, Dec 08, 2020 at 12:31:23PM +0530, Pankaj Dubey wrote:
>
>
> > -----Original Message-----
> > From: Krzysztof Kozlowski <[email protected]>
> > Sent: Tuesday, December 8, 2020 12:35 AM
> > To: Krzysztof Kozlowski <[email protected]>; linux-arm-
> > [email protected]; [email protected]; linux-
> > [email protected]
> > Cc: Sylwester Nawrocki <[email protected]>; Marek Szyprowski
> > <[email protected]>; Bartlomiej Zolnierkiewicz
> > <[email protected]>; Arnd Bergmann <[email protected]>; Chanwoo
> > Choi <[email protected]>; Alim Akhtar <[email protected]>;
> > Pankaj Dubey <[email protected]>
> > Subject: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and
> > merge exynos-asv
> >
> > The Exynos Chip ID driver on Exynos SoCs has so far only informational
> > purpose - to expose the SoC device in sysfs. No other drivers depend on
> it
> > so there is really no benefit of initializing it early.
> >
>
> One of the intention behind initializing Exynos Chip ID driver in early
> stage was to simplify code in arch/arm/mach-exynos specifically calls such
> as soc_is_exynosXXXX.
> But there were lot of resistance from community to add any such calls (or
> exported function) from mach-exynos files to the driver file. Whereas some
> other SoC code is using the same, e.g. tegra_get_chip_id being called from
> mach-tegra files to drivers/soc/tegra/. Unfortunately we could not accept
> similar solution for Exynos SoC and hence could not get rid of
> soc_is_exynosxXXX and similar macros from various file in mach-exynos and
> eventually converting those files into a full-fledged driver files.
>
> Any opinion how can we achieve this if we convert Exynos Chip ID driver to a
> regular driver?

a. Some parts of mach code can be moved to drivers and then use OF calls.

b. The ones which cannot be moved, could use soc_device_match() assuming
they are called after the soc-bus is operational - so after
core_initcalls.

c. The ones which are called early or without cache coherency
(soc_device_match() uses krefs()), cannot be converted.

This chip ID conversion indeed kills case (b) above... which I am not
sure is worth bothering. Which parts of code could be moved like this?
Not mentioning that none of this work have happened since few years...

Best regards,
Krzysztof

2020-12-08 11:56:05

by Pankaj Dubey

[permalink] [raw]

Subject: RE: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv

> -----Original Message-----
> From: Krzysztof Kozlowski <[email protected]>
> Sent: Tuesday, December 8, 2020 12:35 AM
> To: Krzysztof Kozlowski <[email protected]>; linux-arm-
> [email protected]; [email protected]; linux-
> [email protected]
> Cc: Sylwester Nawrocki <[email protected]>; Marek Szyprowski
> <[email protected]>; Bartlomiej Zolnierkiewicz
> <[email protected]>; Arnd Bergmann <[email protected]>; Chanwoo
> Choi <[email protected]>; Alim Akhtar <[email protected]>;
> Pankaj Dubey <[email protected]>
> Subject: [PATCH v2 4/4] soc: samsung: exynos-chipid: convert to driver and
> merge exynos-asv
>
> The Exynos Chip ID driver on Exynos SoCs has so far only informational
> purpose - to expose the SoC device in sysfs. No other drivers depend on
it
> so there is really no benefit of initializing it early.
>

One of the intention behind initializing Exynos Chip ID driver in early
stage was to simplify code in arch/arm/mach-exynos specifically calls such
as soc_is_exynosXXXX.
But there were lot of resistance from community to add any such calls (or
exported function) from mach-exynos files to the driver file. Whereas some
other SoC code is using the same, e.g. tegra_get_chip_id being called from
mach-tegra files to drivers/soc/tegra/. Unfortunately we could not accept
similar solution for Exynos SoC and hence could not get rid of
soc_is_exynosxXXX and similar macros from various file in mach-exynos and
eventually converting those files into a full-fledged driver files.

Any opinion how can we achieve this if we convert Exynos Chip ID driver to a
regular driver?

Thanks,
Pankaj Dubey

> The code would be the most flexible if converted to a regular driver.
> However there is already another driver - Exynos ASV (Adaptive Supply
> Voltage) - which binds to the device node of Chip ID.
>
> The solution is to convert the Exynos Chip ID to a built in driver and
merge
> the Exynos ASV into it.
>
> This has several benefits:
> 1. Although the Exynos ASV driver binds to a device node present in all
> Exynos DTS (generic compatible), it fails to probe except on the
> supported ones (only Exynos5422). This means that the regular boot
> process has a planned/expected device probe failure.
>
> Merging the ASV into Chip ID will remove this probe failure because
> the final driver will always bind, just with disabled ASV features.
>
> 2. Allows to use dev_info() as the SoC bus is present (since
> core_initcall).
>
> 3. Could speed things up because of execution of Chip ID code in a SMP
> environment (after bringing up secondary CPUs, unlike early_initcall),
> This reduces the amount of work to be done early, when the kernel has
> to bring up critical devices.
>
> 5. Makes the Chip ID code defer-probe friendly,
>
> Signed-off-by: Krzysztof Kozlowski <[email protected]>
> ---
> arch/arm/mach-exynos/Kconfig | 1 -
> drivers/soc/samsung/Kconfig | 12 ++---
> drivers/soc/samsung/Makefile | 3 +-
> drivers/soc/samsung/exynos-asv.c | 45 +++++------------
> drivers/soc/samsung/exynos-asv.h | 2 +
> drivers/soc/samsung/exynos-chipid.c | 75 ++++++++++++++++++++---------
> 6 files changed, 70 insertions(+), 68 deletions(-)
>
> diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-
> exynos/Kconfig index 56d272967fc0..5a48abac6af4 100644
> --- a/arch/arm/mach-exynos/Kconfig
> +++ b/arch/arm/mach-exynos/Kconfig
> @@ -13,7 +13,6 @@ menuconfig ARCH_EXYNOS
> select ARM_GIC
> select EXYNOS_IRQ_COMBINER
> select COMMON_CLK_SAMSUNG
> - select EXYNOS_ASV
> select EXYNOS_CHIPID
> select EXYNOS_THERMAL
> select EXYNOS_PMU
> diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
> index fc7f48a92288..5745d7e5908e 100644
> --- a/drivers/soc/samsung/Kconfig
> +++ b/drivers/soc/samsung/Kconfig
> @@ -7,21 +7,19 @@ menuconfig SOC_SAMSUNG
>
> if SOC_SAMSUNG
>
> -config EXYNOS_ASV
> - bool "Exynos Adaptive Supply Voltage support" if COMPILE_TEST
> - depends on (ARCH_EXYNOS && EXYNOS_CHIPID) || COMPILE_TEST
> - select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
> -
> # There is no need to enable these drivers for ARMv8 config
> EXYNOS_ASV_ARM
> bool "Exynos ASV ARMv7-specific driver extensions" if
> COMPILE_TEST
> - depends on EXYNOS_ASV
> + depends on EXYNOS_CHIPID
>
> config EXYNOS_CHIPID
> - bool "Exynos Chipid controller driver" if COMPILE_TEST
> + bool "Exynos ChipID controller and ASV driver" if COMPILE_TEST
> depends on ARCH_EXYNOS || COMPILE_TEST
> + select EXYNOS_ASV_ARM if ARM && ARCH_EXYNOS
> select MFD_SYSCON
> select SOC_BUS
> + help
> + Support for Samsung Exynos SoC ChipID and Adaptive Supply
> Voltage.
>
> config EXYNOS_PMU
> bool "Exynos PMU controller driver" if COMPILE_TEST diff --git
> a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile index
> 59e8e9453f27..0c523a8de4eb 100644
> --- a/drivers/soc/samsung/Makefile
> +++ b/drivers/soc/samsung/Makefile
> @@ -1,9 +1,8 @@
> # SPDX-License-Identifier: GPL-2.0
>
> -obj-$(CONFIG_EXYNOS_ASV) += exynos-asv.o
> obj-$(CONFIG_EXYNOS_ASV_ARM) += exynos5422-asv.o
>
> -obj-$(CONFIG_EXYNOS_CHIPID) += exynos-chipid.o
> +obj-$(CONFIG_EXYNOS_CHIPID) += exynos-chipid.o exynos-asv.o
> obj-$(CONFIG_EXYNOS_PMU) += exynos-pmu.o
>
> obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS) += exynos3250-
> pmu.o exynos4-pmu.o \
> diff --git a/drivers/soc/samsung/exynos-asv.c
> b/drivers/soc/samsung/exynos-asv.c
> index 5daeadc36382..d60af8acc391 100644
> --- a/drivers/soc/samsung/exynos-asv.c
> +++ b/drivers/soc/samsung/exynos-asv.c
> @@ -2,7 +2,9 @@
> /*
> * Copyright (c) 2019 Samsung Electronics Co., Ltd.
> * http://www.samsung.com/
> + * Copyright (c) 2020 Krzysztof Kozlowski <[email protected]>
> * Author: Sylwester Nawrocki <[email protected]>
> + * Author: Krzysztof Kozlowski <[email protected]>
> *
> * Samsung Exynos SoC Adaptive Supply Voltage support
> */
> @@ -10,12 +12,7 @@
> #include <linux/cpu.h>
> #include <linux/device.h>
> #include <linux/errno.h>
> -#include <linux/init.h>
> -#include <linux/mfd/syscon.h>
> -#include <linux/module.h>
> #include <linux/of.h>
> -#include <linux/of_device.h>
> -#include <linux/platform_device.h>
> #include <linux/pm_opp.h>
> #include <linux/regmap.h>
> #include <linux/soc/samsung/exynos-chipid.h>
> @@ -111,7 +108,7 @@ static int exynos_asv_update_opps(struct
> exynos_asv *asv)
> return 0;
> }
>
> -static int exynos_asv_probe(struct platform_device *pdev)
> +int exynos_asv_init(struct device *dev, struct regmap *regmap)
> {
> int (*probe_func)(struct exynos_asv *asv);
> struct exynos_asv *asv;
> @@ -119,21 +116,16 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
> u32 product_id = 0;
> int ret, i;
>
> - asv = devm_kzalloc(&pdev->dev, sizeof(*asv), GFP_KERNEL);
> + asv = devm_kzalloc(dev, sizeof(*asv), GFP_KERNEL);
> if (!asv)
> return -ENOMEM;
>
> - asv->chipid_regmap = device_node_to_regmap(pdev-
> >dev.of_node);
> - if (IS_ERR(asv->chipid_regmap)) {
> - dev_err(&pdev->dev, "Could not find syscon regmap\n");
> - return PTR_ERR(asv->chipid_regmap);
> - }
> -
> + asv->chipid_regmap = regmap;
> + asv->dev = dev;
> ret = regmap_read(asv->chipid_regmap,
> EXYNOS_CHIPID_REG_PRO_ID,
> &product_id);
> if (ret < 0) {
> - dev_err(&pdev->dev, "Cannot read revision from
> ChipID: %d\n",
> - ret);
> + dev_err(dev, "Cannot read revision from ChipID: %d\n", ret);
> return -ENODEV;
> }
>
> @@ -142,7 +134,9 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
> probe_func = exynos5422_asv_init;
> break;
> default:
> - return -ENODEV;
> + dev_dbg(dev, "No ASV support for this SoC\n");
> + devm_kfree(dev, asv);
> + return 0;
> }
>
> cpu_dev = get_cpu_device(0);
> @@ -150,14 +144,11 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
> if (ret < 0)
> return -EPROBE_DEFER;
>
> - ret = of_property_read_u32(pdev->dev.of_node, "samsung,asv-
> bin",
> + ret = of_property_read_u32(dev->of_node, "samsung,asv-bin",
> &asv->of_bin);
> if (ret < 0)
> asv->of_bin = -EINVAL;
>
> - asv->dev = &pdev->dev;
> - dev_set_drvdata(&pdev->dev, asv);
> -
> for (i = 0; i < ARRAY_SIZE(asv->subsys); i++)
> asv->subsys[i].asv = asv;
>
> @@ -167,17 +158,3 @@ static int exynos_asv_probe(struct platform_device
> *pdev)
>
> return exynos_asv_update_opps(asv);
> }
> -
> -static const struct of_device_id exynos_asv_of_device_ids[] = {
> - { .compatible = "samsung,exynos4210-chipid" },
> - {}
> -};
> -
> -static struct platform_driver exynos_asv_driver = {
> - .driver = {
> - .name = "exynos-asv",
> - .of_match_table = exynos_asv_of_device_ids,
> - },
> - .probe = exynos_asv_probe,
> -};
> -module_platform_driver(exynos_asv_driver);
> diff --git a/drivers/soc/samsung/exynos-asv.h
> b/drivers/soc/samsung/exynos-asv.h
> index 3fd1f2acd999..dcbe154db31e 100644
> --- a/drivers/soc/samsung/exynos-asv.h
> +++ b/drivers/soc/samsung/exynos-asv.h
> @@ -68,4 +68,6 @@ static inline u32 exynos_asv_opp_get_frequency(const
> struct exynos_asv_subsys *s
> return __asv_get_table_entry(&subsys->table, level, 0); }
>
> +int exynos_asv_init(struct device *dev, struct regmap *regmap);
> +
> #endif /* __LINUX_SOC_EXYNOS_ASV_H */
> diff --git a/drivers/soc/samsung/exynos-chipid.c
> b/drivers/soc/samsung/exynos-chipid.c
> index b4cd0cc00f45..fa6a9b9f6d70 100644
> --- a/drivers/soc/samsung/exynos-chipid.c
> +++ b/drivers/soc/samsung/exynos-chipid.c
> @@ -2,20 +2,28 @@
> /*
> * Copyright (c) 2019 Samsung Electronics Co., Ltd.
> * http://www.samsung.com/
> + * Copyright (c) 2020 Krzysztof Kozlowski <[email protected]>
> *
> * Exynos - CHIP ID support
> * Author: Pankaj Dubey <[email protected]>
> * Author: Bartlomiej Zolnierkiewicz <[email protected]>
> + * Author: Krzysztof Kozlowski <[email protected]>
> + *
> + * Samsung Exynos SoC Adaptive Supply Voltage and Chip ID support
> */
>
> -#include <linux/io.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> #include <linux/mfd/syscon.h>
> #include <linux/of.h>
> +#include <linux/platform_device.h>
> #include <linux/regmap.h>
> #include <linux/slab.h>
> #include <linux/soc/samsung/exynos-chipid.h>
> #include <linux/sys_soc.h>
>
> +#include "exynos-asv.h"
> +
> static const struct exynos_soc_id {
> const char *name;
> unsigned int id;
> @@ -46,25 +54,17 @@ static const char * __init
> product_id_to_soc_id(unsigned int product_id)
> return NULL;
> }
>
> -static int __init exynos_chipid_early_init(void)
> +static int exynos_chipid_probe(struct platform_device *pdev)
> {
> struct soc_device_attribute *soc_dev_attr;
> struct soc_device *soc_dev;
> struct device_node *root;
> - struct device_node *syscon;
> struct regmap *regmap;
> u32 product_id;
> u32 revision;
> int ret;
>
> - syscon = of_find_compatible_node(NULL, NULL,
> - "samsung,exynos4210-chipid");
> - if (!syscon)
> - return -ENODEV;
> -
> - regmap = device_node_to_regmap(syscon);
> - of_node_put(syscon);
> -
> + regmap = device_node_to_regmap(pdev->dev.of_node);
> if (IS_ERR(regmap))
> return PTR_ERR(regmap);
>
> @@ -74,7 +74,8 @@ static int __init exynos_chipid_early_init(void)
>
> revision = product_id & EXYNOS_REV_MASK;
>
> - soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
> + soc_dev_attr = devm_kzalloc(&pdev->dev, sizeof(*soc_dev_attr),
> + GFP_KERNEL);
> if (!soc_dev_attr)
> return -ENOMEM;
>
> @@ -84,31 +85,57 @@ static int __init exynos_chipid_early_init(void)
> of_property_read_string(root, "model", &soc_dev_attr->machine);
> of_node_put(root);
>
> - soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%x", revision);
> + soc_dev_attr->revision = devm_kasprintf(&pdev->dev, GFP_KERNEL,
> + "%x", revision);
> soc_dev_attr->soc_id = product_id_to_soc_id(product_id);
> if (!soc_dev_attr->soc_id) {
> pr_err("Unknown SoC\n");
> - ret = -ENODEV;
> - goto err;
> + return -ENODEV;
> }
>
> /* please note that the actual registration will be deferred */
> soc_dev = soc_device_register(soc_dev_attr);
> - if (IS_ERR(soc_dev)) {
> - ret = PTR_ERR(soc_dev);
> + if (IS_ERR(soc_dev))
> + return PTR_ERR(soc_dev);
> +
> + ret = exynos_asv_init(&pdev->dev, regmap);
> + if (ret)
> goto err;
> - }
>
> - /* it is too early to use dev_info() here (soc_dev is NULL) */
> - pr_info("soc soc0: Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x]
> Detected\n",
> - soc_dev_attr->soc_id, product_id, revision);
> + platform_set_drvdata(pdev, soc_dev);
> +
> + dev_info(soc_device_to_device(soc_dev),
> + "Exynos: CPU[%s] PRO_ID[0x%x] REV[0x%x] Detected\n",
> + soc_dev_attr->soc_id, product_id, revision);
>
> return 0;
>
> err:
> - kfree(soc_dev_attr->revision);
> - kfree(soc_dev_attr);
> + soc_device_unregister(soc_dev);
> +
> return ret;
> }
>
> -early_initcall(exynos_chipid_early_init);
> +static int exynos_chipid_remove(struct platform_device *pdev) {
> + struct soc_device *soc_dev = platform_get_drvdata(pdev);
> +
> + soc_device_unregister(soc_dev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id exynos_chipid_of_device_ids[] = {
> + { .compatible = "samsung,exynos4210-chipid" },
> + {}
> +};
> +
> +static struct platform_driver exynos_chipid_driver = {
> + .driver = {
> + .name = "exynos-chipid",
> + .of_match_table = exynos_chipid_of_device_ids,
> + },
> + .probe = exynos_chipid_probe,
> + .remove = exynos_chipid_remove,
> +};
> +builtin_platform_driver(exynos_chipid_driver);
> --
> 2.25.1

2021-01-03 18:51:09

by Krzysztof Kozlowski

[permalink] [raw]

Subject: Re: [PATCH v2 1/4] soc: samsung: exynos-asv: don't defer early on not-supported SoCs

On Mon, Dec 07, 2020 at 08:05:14PM +0100, Krzysztof Kozlowski wrote:
> From: Marek Szyprowski <[email protected]>
>
> Check if the SoC is really supported before gathering the needed
> resources. This fixes endless deferred probe on some SoCs other than
> Exynos5422 (like Exynos5410).
>
> Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
> Cc: <[email protected]>
> Signed-off-by: Marek Szyprowski <[email protected]>
> Signed-off-by: Krzysztof Kozlowski <[email protected]>
> ---
> drivers/soc/samsung/exynos-asv.c | 10 +++++-----

Thanks, applied.

Best regards,
Krzysztof

2021-01-03 19:38:43

by Krzysztof Kozlowski

[permalink] [raw]

Subject: Re: (subset) [PATCH v2 0/4] soc: samsung: exynos-chipid and asv improvements

On Mon, 7 Dec 2020 20:05:13 +0100, Krzysztof Kozlowski wrote:
> Changes since v1:
> 1. Drop patch "soc: samsung: exynos-chipid: initialize later - with
> arch_initcall" which is now superseded by convertin to a driver.
> 2. Include Marek's patch, just for the reference and rebase.
> 3. Add patch "soc: samsung: exynos-asv: handle reading revision register
> error".
> 4. Add patch "soc: samsung: exynos-chipid: convert to driver and merge
> exynos-asv".
>
> [...]

Applied, thanks!

[4/4] soc: samsung: exynos-chipid: convert to driver and merge exynos-asv
commit: 352bfbb3e0230c96b2bce00d2ac3f0de303cc7b6

Best regards,
--
Krzysztof Kozlowski <[email protected]>

2021-01-03 19:53:32

by Krzysztof Kozlowski

[permalink] [raw]

Subject: Re: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision register error

On Mon, Dec 07, 2020 at 08:05:15PM +0100, Krzysztof Kozlowski wrote:
> If regmap_read() fails, the product_id local variable will contain
> random value from the stack. Do not try to parse such value and fail
> the ASV driver probe.
>
> Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
> Cc: <[email protected]>
> Signed-off-by: Krzysztof Kozlowski <[email protected]>
> ---
> drivers/soc/samsung/exynos-asv.c | 8 +++++++-

Applied.

Best regards,
Krzysztof