mmc: Add mmc pstore backend support

Adding mmc pstore backend support to be able to write to pstore device. Code is based on mtdpstore. Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
intel-lab-lkp · Dec 22, 2022 · 73afc48 · 73afc48
1 parent 76d62f2
commit 73afc48
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diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
@@ -34,9 +34,22 @@ config PWRSEQ_SIMPLE
 	  This driver can also be built as a module. If so, the module
 	  will be called pwrseq_simple.
 
+config MMC_PSTORE_BACKEND
+	bool "Log panic/oops to a MMC buffer"
+	depends on MMC_BLOCK
+	help
+	  This option will let you create platform backend to store kmsg
+	  crash dumps to a user specified MMC device. This is primarily
+	  based on pstore/blk.
+
+config MMC_PSTORE
+	tristate
+	select PSTORE_BLK
+
 config MMC_BLOCK
 	tristate "MMC block device driver"
 	depends on BLOCK
+	select MMC_PSTORE if MMC_PSTORE_BACKEND=y
 	default y
 	help
 	  Say Y here to enable the MMC block device driver support.

diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_PWRSEQ_EMMC)	+= pwrseq_emmc.o
 mmc_core-$(CONFIG_DEBUG_FS)	+= debugfs.o
 obj-$(CONFIG_MMC_BLOCK)		+= mmc_block.o
 mmc_block-objs			:= block.o queue.o
+mmc_block-$(CONFIG_MMC_PSTORE)	+= mmcpstore.o
 obj-$(CONFIG_MMC_TEST)		+= mmc_test.o
 obj-$(CONFIG_SDIO_UART)		+= sdio_uart.o
 mmc_core-$(CONFIG_MMC_CRYPTO)	+= crypto.o
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
@@ -2982,6 +2982,9 @@ static int mmc_blk_probe(struct mmc_card *card)
 	if (ret)
 		goto out;
 
+	if (mmc_card_mmc(card) || mmc_card_sd(card))
+		mmcpstore_register(card, md->disk->disk_name);
+
 	/* Add two debugfs entries */
 	mmc_blk_add_debugfs(card, md);
 
@@ -3131,6 +3134,7 @@ static void __exit mmc_blk_exit(void)
 	unregister_blkdev(MMC_BLOCK_MAJOR, "mmc");
 	unregister_chrdev_region(mmc_rpmb_devt, MAX_DEVICES);
 	bus_unregister(&mmc_rpmb_bus_type);
+	unregister_mmcpstore();
 }
 
 module_init(mmc_blk_init);

diff --git a/drivers/mmc/core/block.h b/drivers/mmc/core/block.h
@@ -16,5 +16,14 @@ void mmc_blk_mq_recovery(struct mmc_queue *mq);
 struct work_struct;
 
 void mmc_blk_mq_complete_work(struct work_struct *work);
+#if IS_ENABLED(CONFIG_MMC_PSTORE)
+sector_t mmc_blk_get_part(struct mmc_card *card, int part_num, sector_t *size);
+void mmcpstore_register(struct mmc_card *card, const char *disk_name);
+void unregister_mmcpstore(void);
+#else
+static inline void mmcpstore_register(struct mmc_card *card,
+				      const char *disk_name) {}
+static inline void unregister_mmcpstore(void) {}
+#endif
 
 #endif