From 0bc448b49e8a017e16edf843baf5b4221e191b1f Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 9 Dec 2019 14:48:23 +0100 Subject: [PATCH] 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 Signed-off-by: Miquel Raynal --- 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 a9f7964e2edb..8f7f966fa9a7 100644 --- a/drivers/mtd/maps/physmap-core.c +++ b/drivers/mtd/maps/physmap-core.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #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;