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mmc: Support kmsg dumper based on pstore/blk
This patch introduces to mmcpstore. The functioning of mmcpstore is similar to mtdpstore. mmcpstore works on FTL based flash devices whereas mtdpstore works on raw flash devices. When the system crashes, mmcpstore stores the kmsg panic and oops logs to a user specified MMC device. It collects the details about the host MMC device through pstore/blk "blkdev" parameter. The user can specify the MMC device in many ways by checking in Documentation/admin-guide/pstore-blk.rst. The individual mmc host drivers have to define suitable polling and cleanup subroutines to write kmsg panic/oops logs through mmcpstore. These new host operations are needed as pstore panic write runs with interrupts disabled. Signed-off-by: Bhaskara Budiredla <bbudiredla@marvell.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,227 @@ | ||
| // SPDX-License-Identifier: GPL-2.0 | ||
| /* | ||
| * MMC pstore support based on pstore/blk | ||
| * | ||
| * Copyright (c) 2020 Marvell. | ||
| * Author: Bhaskara Budiredla <bbudiredla@marvell.com> | ||
| */ | ||
|
|
||
| #define pr_fmt(fmt) "mmcpstore: " fmt | ||
|
|
||
| #include <linux/kernel.h> | ||
| #include <linux/module.h> | ||
| #include <linux/pstore_blk.h> | ||
| #include <linux/blkdev.h> | ||
| #include <linux/mount.h> | ||
| #include <linux/slab.h> | ||
| #include <linux/mmc/mmc.h> | ||
| #include <linux/mmc/host.h> | ||
| #include <linux/mmc/card.h> | ||
| #include <linux/scatterlist.h> | ||
| #include "block.h" | ||
| #include "card.h" | ||
| #include "core.h" | ||
|
|
||
| static struct mmcpstore_context { | ||
| char dev_name[BDEVNAME_SIZE]; | ||
| int partno; | ||
| sector_t start_sect; | ||
| sector_t size; | ||
| struct pstore_blk_config conf; | ||
| struct pstore_blk_info info; | ||
|
|
||
| struct mmc_card *card; | ||
| struct mmc_request *mrq; | ||
| } oops_cxt; | ||
|
|
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| static void mmc_prep_req(struct mmc_request *mrq, | ||
| unsigned int sect_offset, unsigned int nsects, | ||
| struct scatterlist *sg, u32 opcode, unsigned int flags) | ||
| { | ||
| mrq->cmd->opcode = opcode; | ||
| mrq->cmd->arg = sect_offset; | ||
| mrq->cmd->flags = MMC_RSP_R1 | MMC_CMD_ADTC; | ||
|
|
||
| if (nsects == 1) { | ||
| mrq->stop = NULL; | ||
| } else { | ||
| mrq->stop->opcode = MMC_STOP_TRANSMISSION; | ||
| mrq->stop->arg = 0; | ||
| mrq->stop->flags = MMC_RSP_R1B | MMC_CMD_AC; | ||
| } | ||
|
|
||
| mrq->data->blksz = SECTOR_SIZE; | ||
| mrq->data->blocks = nsects; | ||
| mrq->data->flags = flags; | ||
| mrq->data->sg = sg; | ||
| mrq->data->sg_len = 1; | ||
| } | ||
|
|
||
| static int mmcpstore_panic_write_req(const char *buf, | ||
| unsigned int nsects, unsigned int sect_offset) | ||
| { | ||
| struct mmcpstore_context *cxt = &oops_cxt; | ||
| struct mmc_request *mrq = cxt->mrq; | ||
| struct mmc_card *card = cxt->card; | ||
| struct mmc_host *host = card->host; | ||
| struct scatterlist sg; | ||
| u32 opcode; | ||
| int ret; | ||
|
|
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| opcode = (nsects > 1) ? MMC_WRITE_MULTIPLE_BLOCK : MMC_WRITE_BLOCK; | ||
| mmc_prep_req(mrq, sect_offset, nsects, &sg, opcode, MMC_DATA_WRITE); | ||
| sg_init_one(&sg, buf, (nsects << SECTOR_SHIFT)); | ||
| mmc_set_data_timeout(mrq->data, cxt->card); | ||
|
|
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| ret = mmc_claim_host_async(host); | ||
| if (ret) | ||
| return ret; | ||
|
|
||
| mmc_wait_for_pstore_req(host, mrq); | ||
| return 0; | ||
| } | ||
|
|
||
| static int mmcpstore_panic_write(const char *buf, sector_t off, sector_t sects) | ||
| { | ||
| struct mmcpstore_context *cxt = &oops_cxt; | ||
| int ret; | ||
|
|
||
| ret = mmcpstore_panic_write_req(buf, sects, cxt->start_sect + off); | ||
| if (ret) | ||
| return ret; | ||
|
|
||
| return 0; | ||
| } | ||
|
|
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| static struct block_device *mmcpstore_open_backend(const char *device) | ||
| { | ||
| struct block_device *bdev; | ||
| dev_t devt; | ||
|
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| bdev = blkdev_get_by_path(device, FMODE_READ, NULL); | ||
| if (IS_ERR(bdev)) { | ||
| devt = name_to_dev_t(device); | ||
| if (devt == 0) | ||
| return ERR_PTR(-ENODEV); | ||
|
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| bdev = blkdev_get_by_dev(devt, FMODE_READ, NULL); | ||
| if (IS_ERR(bdev)) | ||
| return bdev; | ||
| } | ||
|
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| return bdev; | ||
| } | ||
|
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| static void mmcpstore_close_backend(struct block_device *bdev) | ||
| { | ||
| if (!bdev) | ||
| return; | ||
| blkdev_put(bdev, FMODE_READ); | ||
| } | ||
|
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||
| void mmcpstore_card_set(struct mmc_card *card, const char *disk_name) | ||
| { | ||
| struct mmcpstore_context *cxt = &oops_cxt; | ||
| struct pstore_blk_config *conf = &cxt->conf; | ||
| struct pstore_blk_info *info = &cxt->info; | ||
| struct block_device *bdev; | ||
| struct mmc_command *stop; | ||
| struct mmc_command *cmd; | ||
| struct mmc_request *mrq; | ||
| struct mmc_data *data; | ||
| int ret; | ||
|
|
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| ret = pstore_blk_get_config(conf); | ||
| if (!conf->device[0]) { | ||
| pr_debug("psblk backend is empty\n"); | ||
| return; | ||
| } | ||
|
|
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| /* Multiple backend devices not allowed */ | ||
| if (cxt->dev_name[0]) | ||
| return; | ||
|
|
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| bdev = mmcpstore_open_backend(conf->device); | ||
| if (IS_ERR(bdev)) { | ||
| pr_err("%s failed to open with %ld\n", | ||
| conf->device, PTR_ERR(bdev)); | ||
| return; | ||
| } | ||
|
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| bdevname(bdev, cxt->dev_name); | ||
| cxt->partno = bdev->bd_part->partno; | ||
| mmcpstore_close_backend(bdev); | ||
|
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| if (strncmp(cxt->dev_name, disk_name, strlen(disk_name))) | ||
| return; | ||
|
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| cxt->start_sect = mmc_blk_get_part(card, cxt->partno, &cxt->size); | ||
| if (!cxt->start_sect) { | ||
| pr_err("Non-existent partition %d selected\n", cxt->partno); | ||
| return; | ||
| } | ||
|
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| /* Check for host mmc panic write polling function definitions */ | ||
| if (!card->host->ops->req_cleanup_pending || | ||
| !card->host->ops->req_completion_poll) | ||
| return; | ||
|
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| cxt->card = card; | ||
|
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| mrq = kzalloc(sizeof(struct mmc_request), GFP_KERNEL); | ||
| if (!mrq) | ||
| goto out; | ||
|
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| cmd = kzalloc(sizeof(struct mmc_command), GFP_KERNEL); | ||
| if (!cmd) | ||
| goto free_mrq; | ||
|
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| stop = kzalloc(sizeof(struct mmc_command), GFP_KERNEL); | ||
| if (!stop) | ||
| goto free_cmd; | ||
|
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| data = kzalloc(sizeof(struct mmc_data), GFP_KERNEL); | ||
| if (!data) | ||
| goto free_stop; | ||
|
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| mrq->cmd = cmd; | ||
| mrq->data = data; | ||
| mrq->stop = stop; | ||
| cxt->mrq = mrq; | ||
|
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| info->major = MMC_BLOCK_MAJOR; | ||
| info->flags = PSTORE_FLAGS_DMESG; | ||
| info->panic_write = mmcpstore_panic_write; | ||
| ret = register_pstore_blk(info); | ||
| if (ret) { | ||
| pr_err("%s registering with psblk failed (%d)\n", | ||
| cxt->dev_name, ret); | ||
| goto free_data; | ||
| } | ||
|
|
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| pr_info("%s registered as psblk backend\n", cxt->dev_name); | ||
| return; | ||
|
|
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| free_data: | ||
| kfree(data); | ||
| free_stop: | ||
| kfree(stop); | ||
| free_cmd: | ||
| kfree(cmd); | ||
| free_mrq: | ||
| kfree(mrq); | ||
| out: | ||
| return; | ||
| } | ||
|
|
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| void unregister_mmcpstore(void) | ||
| { | ||
| struct mmcpstore_context *cxt = &oops_cxt; | ||
|
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| unregister_pstore_blk(MMC_BLOCK_MAJOR); | ||
| kfree(cxt->mrq->data); | ||
| kfree(cxt->mrq->stop); | ||
| kfree(cxt->mrq->cmd); | ||
| kfree(cxt->mrq); | ||
| cxt->card = NULL; | ||
| } |
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