diff options
author | Geert Uytterhoeven <geert+renesas@glider.be> | 2019-12-09 14:48:23 +0100 |
---|---|---|
committer | Miquel Raynal <miquel.raynal@bootlin.com> | 2020-01-27 16:55:31 +0100 |
commit | 0bc448b49e8a017e16edf843baf5b4221e191b1f (patch) | |
tree | a69825062930c503ea2adeb6aa53543c0aa0677e | |
parent | 2a0b390b472b7be8909beb77d47db361b613cdc8 (diff) | |
download | linux-stable-0bc448b49e8a017e16edf843baf5b4221e191b1f.tar.gz linux-stable-0bc448b49e8a017e16edf843baf5b4221e191b1f.tar.bz2 linux-stable-0bc448b49e8a017e16edf843baf5b4221e191b1f.zip |
mtd: maps: physmap: Add minimal Runtime PM support
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>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
-rw-r--r-- | drivers/mtd/maps/physmap-core.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c index a9f7964e2edb..8f7f966fa9a7 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; |