| Message ID | 20200115131323.6883-1-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 0bc448b49e8a017e16edf843baf5b4221e191b1f |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
| Series | [resend] mtd: maps: physmap: Add minimal Runtime PM support | expand |
Hi Geert, Thanks for your work. On 2020-01-15 14:13:23 +0100, Geert Uytterhoeven wrote: > Add minimal runtime PM support (enable on probe, disable on remove), to > ensure proper operation with a parent device that uses runtime PM. > > This is needed on systems where the FLASH is connected to a bus > controller that is contained in a PM domain and/or has a gateable > functional clock. In such cases, before accessing any device connected > to the external bus, the PM domain must be powered up, and/or the > functional clock must be enabled, which is typically handled through > runtime PM by the bus controller driver. > > An example of this is the Renesas APE6-EVM development board, which has > an Ethernet controller and a CFI FLASH connected to the Bus State > Controller (BSC) of an R-Mobile APE6 SoC. > As long as the Ethernet driver, which had Runtime PM support since > commit 3a611e26e958b037 ("net/smsc911x: Add minimal runtime PM > support"), keeps the BSC powered, accessing the FLASH works. > When the ethernet node in r8a73a4-ape6evm.dts is disabled, the BSC is > never powered up, and the kernel crashes when trying to access the > FLASH: > > Unhandled fault: imprecise external abort (0x1406) at 0x00000000 > pgd = (ptrval) > [00000000] *pgd=7fef2835 > Internal error: : 1406 [#1] SMP ARM > CPU: 0 PID: 122 Comm: hd Tainted: G W 5.5.0-rc1-ape6evm-00814-g38ca966db25b9dbd-dirty #136 > Hardware name: Generic R8A73A4 (Flattened Device Tree) > PC is at chip_ready+0x12c/0x380 > LR is at chip_ready+0x10c/0x380 > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> > --- > Probably the device should be powered down after probing, and powered > up/down on-demand in the various {get,put}_chip() functions. However, > that is an optimization which touches more intimidate details of the > internal MTD API, and can be done later. > --- > drivers/mtd/maps/physmap-core.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c > index a9f7964e2edb6668..8f7f966fa9a7ee8a 100644 > --- a/drivers/mtd/maps/physmap-core.c > +++ b/drivers/mtd/maps/physmap-core.c > @@ -38,6 +38,7 @@ > #include <linux/mtd/cfi_endian.h> > #include <linux/io.h> > #include <linux/of_device.h> > +#include <linux/pm_runtime.h> > #include <linux/gpio/consumer.h> > > #include "physmap-gemini.h" > @@ -64,16 +65,16 @@ static int physmap_flash_remove(struct platform_device *dev) > { > struct physmap_flash_info *info; > struct physmap_flash_data *physmap_data; > - int i, err; > + int i, err = 0; > > info = platform_get_drvdata(dev); > if (!info) > - return 0; > + goto out; > > if (info->cmtd) { > err = mtd_device_unregister(info->cmtd); > if (err) > - return err; > + goto out; > > if (info->cmtd != info->mtds[0]) > mtd_concat_destroy(info->cmtd); > @@ -88,7 +89,10 @@ static int physmap_flash_remove(struct platform_device *dev) > if (physmap_data && physmap_data->exit) > physmap_data->exit(dev); > > - return 0; > +out: > + pm_runtime_put(&dev->dev); > + pm_runtime_disable(&dev->dev); > + return err; > } > > static void physmap_set_vpp(struct map_info *map, int state) > @@ -484,13 +488,19 @@ static int physmap_flash_probe(struct platform_device *dev) > return -EINVAL; > } > > + pm_runtime_enable(&dev->dev); > + pm_runtime_get_sync(&dev->dev); > + > if (dev->dev.of_node) > err = physmap_flash_of_init(dev); > else > err = physmap_flash_pdata_init(dev); > > - if (err) > + if (err) { > + pm_runtime_put(&dev->dev); > + pm_runtime_disable(&dev->dev); > return err; > + } > > for (i = 0; i < info->nmaps; i++) { > struct resource *res; > -- > 2.17.1 >
Geert Uytterhoeven <geert+renesas@glider.be> writes: > Add minimal runtime PM support (enable on probe, disable on remove), to > ensure proper operation with a parent device that uses runtime PM. > > This is needed on systems where the FLASH is connected to a bus > controller that is contained in a PM domain and/or has a gateable > functional clock. In such cases, before accessing any device connected > to the external bus, the PM domain must be powered up, and/or the > functional clock must be enabled, which is typically handled through > runtime PM by the bus controller driver. > > An example of this is the Renesas APE6-EVM development board, which has > an Ethernet controller and a CFI FLASH connected to the Bus State > Controller (BSC) of an R-Mobile APE6 SoC. > As long as the Ethernet driver, which had Runtime PM support since > commit 3a611e26e958b037 ("net/smsc911x: Add minimal runtime PM > support"), keeps the BSC powered, accessing the FLASH works. > When the ethernet node in r8a73a4-ape6evm.dts is disabled, the BSC is > never powered up, and the kernel crashes when trying to access the > FLASH: > > Unhandled fault: imprecise external abort (0x1406) at 0x00000000 > pgd = (ptrval) > [00000000] *pgd=7fef2835 > Internal error: : 1406 [#1] SMP ARM > CPU: 0 PID: 122 Comm: hd Tainted: G W 5.5.0-rc1-ape6evm-00814-g38ca966db25b9dbd-dirty #136 > Hardware name: Generic R8A73A4 (Flattened Device Tree) > PC is at chip_ready+0x12c/0x380 > LR is at chip_ready+0x10c/0x380 > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Kevin Hilman <khilman@baylibre.com> > --- > Probably the device should be powered down after probing, and powered > up/down on-demand in the various {get,put}_chip() functions. However, > that is an optimization which touches more intimidate details of the > internal MTD API, and can be done later. Agreed. Without that, the BSC (in your example) will never get powered off as long as there's a flash device pobed. Kevin > --- > drivers/mtd/maps/physmap-core.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c > index a9f7964e2edb6668..8f7f966fa9a7ee8a 100644 > --- a/drivers/mtd/maps/physmap-core.c > +++ b/drivers/mtd/maps/physmap-core.c > @@ -38,6 +38,7 @@ > #include <linux/mtd/cfi_endian.h> > #include <linux/io.h> > #include <linux/of_device.h> > +#include <linux/pm_runtime.h> > #include <linux/gpio/consumer.h> > > #include "physmap-gemini.h" > @@ -64,16 +65,16 @@ static int physmap_flash_remove(struct platform_device *dev) > { > struct physmap_flash_info *info; > struct physmap_flash_data *physmap_data; > - int i, err; > + int i, err = 0; > > info = platform_get_drvdata(dev); > if (!info) > - return 0; > + goto out; > > if (info->cmtd) { > err = mtd_device_unregister(info->cmtd); > if (err) > - return err; > + goto out; > > if (info->cmtd != info->mtds[0]) > mtd_concat_destroy(info->cmtd); > @@ -88,7 +89,10 @@ static int physmap_flash_remove(struct platform_device *dev) > if (physmap_data && physmap_data->exit) > physmap_data->exit(dev); > > - return 0; > +out: > + pm_runtime_put(&dev->dev); > + pm_runtime_disable(&dev->dev); > + return err; > } > > static void physmap_set_vpp(struct map_info *map, int state) > @@ -484,13 +488,19 @@ static int physmap_flash_probe(struct platform_device *dev) > return -EINVAL; > } > > + pm_runtime_enable(&dev->dev); > + pm_runtime_get_sync(&dev->dev); > + > if (dev->dev.of_node) > err = physmap_flash_of_init(dev); > else > err = physmap_flash_pdata_init(dev); > > - if (err) > + if (err) { > + pm_runtime_put(&dev->dev); > + pm_runtime_disable(&dev->dev); > return err; > + } > > for (i = 0; i < info->nmaps; i++) { > struct resource *res; > -- > 2.17.1
diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c index a9f7964e2edb6668..8f7f966fa9a7ee8a 100644 --- a/drivers/mtd/maps/physmap-core.c +++ b/drivers/mtd/maps/physmap-core.c @@ -38,6 +38,7 @@ #include <linux/mtd/cfi_endian.h> #include <linux/io.h> #include <linux/of_device.h> +#include <linux/pm_runtime.h> #include <linux/gpio/consumer.h> #include "physmap-gemini.h" @@ -64,16 +65,16 @@ static int physmap_flash_remove(struct platform_device *dev) { struct physmap_flash_info *info; struct physmap_flash_data *physmap_data; - int i, err; + int i, err = 0; info = platform_get_drvdata(dev); if (!info) - return 0; + goto out; if (info->cmtd) { err = mtd_device_unregister(info->cmtd); if (err) - return err; + goto out; if (info->cmtd != info->mtds[0]) mtd_concat_destroy(info->cmtd); @@ -88,7 +89,10 @@ static int physmap_flash_remove(struct platform_device *dev) if (physmap_data && physmap_data->exit) physmap_data->exit(dev); - return 0; +out: + pm_runtime_put(&dev->dev); + pm_runtime_disable(&dev->dev); + return err; } static void physmap_set_vpp(struct map_info *map, int state) @@ -484,13 +488,19 @@ static int physmap_flash_probe(struct platform_device *dev) return -EINVAL; } + pm_runtime_enable(&dev->dev); + pm_runtime_get_sync(&dev->dev); + if (dev->dev.of_node) err = physmap_flash_of_init(dev); else err = physmap_flash_pdata_init(dev); - if (err) + if (err) { + pm_runtime_put(&dev->dev); + pm_runtime_disable(&dev->dev); return err; + } for (i = 0; i < info->nmaps; i++) { struct resource *res;
Add minimal runtime PM support (enable on probe, disable on remove), to ensure proper operation with a parent device that uses runtime PM. This is needed on systems where the FLASH is connected to a bus controller that is contained in a PM domain and/or has a gateable functional clock. In such cases, before accessing any device connected to the external bus, the PM domain must be powered up, and/or the functional clock must be enabled, which is typically handled through runtime PM by the bus controller driver. An example of this is the Renesas APE6-EVM development board, which has an Ethernet controller and a CFI FLASH connected to the Bus State Controller (BSC) of an R-Mobile APE6 SoC. As long as the Ethernet driver, which had Runtime PM support since commit 3a611e26e958b037 ("net/smsc911x: Add minimal runtime PM support"), keeps the BSC powered, accessing the FLASH works. When the ethernet node in r8a73a4-ape6evm.dts is disabled, the BSC is never powered up, and the kernel crashes when trying to access the FLASH: Unhandled fault: imprecise external abort (0x1406) at 0x00000000 pgd = (ptrval) [00000000] *pgd=7fef2835 Internal error: : 1406 [#1] SMP ARM CPU: 0 PID: 122 Comm: hd Tainted: G W 5.5.0-rc1-ape6evm-00814-g38ca966db25b9dbd-dirty #136 Hardware name: Generic R8A73A4 (Flattened Device Tree) PC is at chip_ready+0x12c/0x380 LR is at chip_ready+0x10c/0x380 Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- Probably the device should be powered down after probing, and powered up/down on-demand in the various {get,put}_chip() functions. However, that is an optimization which touches more intimidate details of the internal MTD API, and can be done later. --- drivers/mtd/maps/physmap-core.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)