RE: [PATCH v3 1/1] misc: sram: add dev_pm_ops to support module power gate
Hi GregKH,
Can you please take a look at this patch?
Thanks,
Shenwei
> -Original Message-
> From: linux-arm-kernel [mailto:linux-arm-kernel-boun...@lists.infradead.org]
> On
> Behalf Of Shenwei Wang
> Sent: 2015年7月30日 11:11
> To: gre...@linuxfoundation.org; a...@arndb.de
> Cc: Huang Yongcai-B20788; linux-arm-ker...@lists.infradead.org
> Subject: [PATCH v3 1/1] misc: sram: add dev_pm_ops to support module power
> gate
>
> When system goes into low power states like SUSPEND_MEM and HIBERNATION,
> the hardware IP block may be powered off to reduce the power consumption.
> This power down will lost all the data inside the ram. This patch added the
> dev_pm_ops and implemented two callbacks: suspend_noirq and resume_noirq,
> which will save the data in the on-chip-ram right before power down and
> restore
> it after system resumes.
>
> A new property string named "can-power-gate" is added to the devicetree
> bindings too.
>
> Signed-off-by: Shenwei Wang
> Signed-off-by: Anson Huang
> ---
> Change log:
>
> PATCH v3
> Removed the unnecessary clk_enable/clk_disable.
>
> PATCH v2
> Use vmalloc to allocate the SRAM backup memory.
> Code clean up.
>
> Documentation/devicetree/bindings/misc/sram.txt | 2 ++
> drivers/misc/sram.c | 42
> +
> 2 files changed, 44 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/misc/sram.txt
> b/Documentation/devicetree/bindings/misc/sram.txt
> index 36cbe5a..1170086 100644
> --- a/Documentation/devicetree/bindings/misc/sram.txt
> +++ b/Documentation/devicetree/bindings/misc/sram.txt
> @@ -33,6 +33,8 @@ Optional properties in the area nodes:
>
> - compatible : standard definition, should contain a vendor specific string
> in the form ,[-]
> +- can-power-gate: a property to tell the driver that the sram can support
> + power gate
>
> Example:
>
> diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index 15c33cc..db9f1fa
> 100644
> --- a/drivers/misc/sram.c
> +++ b/drivers/misc/sram.c
> @@ -30,7 +30,9 @@
>
> struct sram_dev {
> struct device *dev;
> + void *power_off_save;
> void __iomem *virt_base;
> + u32 size;
>
> struct gen_pool *pool;
> struct clk *clk;
> @@ -156,6 +158,33 @@ static int sram_reserve_regions(struct sram_dev
> *sram, struct resource *res)
> return ret;
> }
>
> +static int sram_suspend_noirq(struct device *dev) {
> + struct platform_device *pdev = to_platform_device(dev);
> + struct sram_dev *sram = platform_get_drvdata(pdev);
> +
> + if (!sram->power_off_save)
> + return 0;
> +
> + /* Save necessary regs */
> + memcpy(sram->power_off_save, sram->virt_base, sram->size);
> +
> + return 0;
> +}
> +
> +static int sram_resume_noirq(struct device *dev) {
> + struct platform_device *pdev = to_platform_device(dev);
> + struct sram_dev *sram = platform_get_drvdata(pdev);
> +
> + if (!sram->power_off_save)
> + return 0;
> +
> + memcpy(sram->virt_base, sram->power_off_save, sram->size);
> +
> + return 0;
> +}
> +
> static int sram_probe(struct platform_device *pdev) {
> struct sram_dev *sram;
> @@ -176,6 +205,7 @@ static int sram_probe(struct platform_device *pdev)
> }
>
> size = resource_size(res);
> + sram->size = size;
>
> if (!devm_request_mem_region(sram->dev, res->start, size, pdev->name)) {
> dev_err(sram->dev, "could not request region for resource\n");
> @@
> -203,6 +233,9 @@ static int sram_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, sram);
>
> + if (of_property_read_bool(pdev->dev.of_node, "can-power-gate"))
> + sram->power_off_save = vmalloc(size);
> +
> dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n",
> gen_pool_size(sram->pool) / 1024, sram->virt_base);
>
> @@ -219,6 +252,9 @@ static int sram_remove(struct platform_device *pdev)
> if (sram->clk)
> clk_disable_unprepare(sram->clk);
>
> + if (sram->power_off_save)
> + vfree(sram->power_off_save);
> +
> return 0;
> }
>
> @@ -229,10 +265,16 @@ static const struct of_device_id sram_dt_ids[] = { };
> #endif
>
> +static const struct dev_pm_ops sram_pm_ops = {
> + .suspend_noirq = sram_suspend_noirq,
> + .resume_noirq = sram_resume_noirq,
> +};
> +
> static struct platform_driver sram_driver = {
> .driver = {
> .name = "sram",
> .of_match_table = of_match_ptr(sram_dt_ids),
> + .pm = _pm_ops,
> },
> .probe = sram_probe,
> .remove = sram_remove,
> --
> 2.5.0.rc2
>
>
>
> ___
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RE: [PATCH v3 1/1] misc: sram: add dev_pm_ops to support module power gate
Hi GregKH,
Can you please take a look at this patch?
Thanks,
Shenwei
-Original Message-
From: linux-arm-kernel [mailto:linux-arm-kernel-boun...@lists.infradead.org]
On
Behalf Of Shenwei Wang
Sent: 2015年7月30日 11:11
To: gre...@linuxfoundation.org; a...@arndb.de
Cc: Huang Yongcai-B20788; linux-arm-ker...@lists.infradead.org
Subject: [PATCH v3 1/1] misc: sram: add dev_pm_ops to support module power
gate
When system goes into low power states like SUSPEND_MEM and HIBERNATION,
the hardware IP block may be powered off to reduce the power consumption.
This power down will lost all the data inside the ram. This patch added the
dev_pm_ops and implemented two callbacks: suspend_noirq and resume_noirq,
which will save the data in the on-chip-ram right before power down and
restore
it after system resumes.
A new property string named can-power-gate is added to the devicetree
bindings too.
Signed-off-by: Shenwei Wang shenwei.w...@freescale.com
Signed-off-by: Anson Huang b20...@freescale.com
---
Change log:
PATCH v3
Removed the unnecessary clk_enable/clk_disable.
PATCH v2
Use vmalloc to allocate the SRAM backup memory.
Code clean up.
Documentation/devicetree/bindings/misc/sram.txt | 2 ++
drivers/misc/sram.c | 42
+
2 files changed, 44 insertions(+)
diff --git a/Documentation/devicetree/bindings/misc/sram.txt
b/Documentation/devicetree/bindings/misc/sram.txt
index 36cbe5a..1170086 100644
--- a/Documentation/devicetree/bindings/misc/sram.txt
+++ b/Documentation/devicetree/bindings/misc/sram.txt
@@ -33,6 +33,8 @@ Optional properties in the area nodes:
- compatible : standard definition, should contain a vendor specific string
in the form vendor,[device-]usage
+- can-power-gate: a property to tell the driver that the sram can support
+ power gate
Example:
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index 15c33cc..db9f1fa
100644
--- a/drivers/misc/sram.c
+++ b/drivers/misc/sram.c
@@ -30,7 +30,9 @@
struct sram_dev {
struct device *dev;
+ void *power_off_save;
void __iomem *virt_base;
+ u32 size;
struct gen_pool *pool;
struct clk *clk;
@@ -156,6 +158,33 @@ static int sram_reserve_regions(struct sram_dev
*sram, struct resource *res)
return ret;
}
+static int sram_suspend_noirq(struct device *dev) {
+ struct platform_device *pdev = to_platform_device(dev);
+ struct sram_dev *sram = platform_get_drvdata(pdev);
+
+ if (!sram-power_off_save)
+ return 0;
+
+ /* Save necessary regs */
+ memcpy(sram-power_off_save, sram-virt_base, sram-size);
+
+ return 0;
+}
+
+static int sram_resume_noirq(struct device *dev) {
+ struct platform_device *pdev = to_platform_device(dev);
+ struct sram_dev *sram = platform_get_drvdata(pdev);
+
+ if (!sram-power_off_save)
+ return 0;
+
+ memcpy(sram-virt_base, sram-power_off_save, sram-size);
+
+ return 0;
+}
+
static int sram_probe(struct platform_device *pdev) {
struct sram_dev *sram;
@@ -176,6 +205,7 @@ static int sram_probe(struct platform_device *pdev)
}
size = resource_size(res);
+ sram-size = size;
if (!devm_request_mem_region(sram-dev, res-start, size, pdev-name)) {
dev_err(sram-dev, could not request region for resource\n);
@@
-203,6 +233,9 @@ static int sram_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, sram);
+ if (of_property_read_bool(pdev-dev.of_node, can-power-gate))
+ sram-power_off_save = vmalloc(size);
+
dev_dbg(sram-dev, SRAM pool: %zu KiB @ 0x%p\n,
gen_pool_size(sram-pool) / 1024, sram-virt_base);
@@ -219,6 +252,9 @@ static int sram_remove(struct platform_device *pdev)
if (sram-clk)
clk_disable_unprepare(sram-clk);
+ if (sram-power_off_save)
+ vfree(sram-power_off_save);
+
return 0;
}
@@ -229,10 +265,16 @@ static const struct of_device_id sram_dt_ids[] = { };
#endif
+static const struct dev_pm_ops sram_pm_ops = {
+ .suspend_noirq = sram_suspend_noirq,
+ .resume_noirq = sram_resume_noirq,
+};
+
static struct platform_driver sram_driver = {
.driver = {
.name = sram,
.of_match_table = of_match_ptr(sram_dt_ids),
+ .pm = sram_pm_ops,
},
.probe = sram_probe,
.remove = sram_remove,
--
2.5.0.rc2
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