diff options
Diffstat (limited to 'drivers/mmc/core/mmcpstore.c')
| -rw-r--r-- | drivers/mmc/core/mmcpstore.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/drivers/mmc/core/mmcpstore.c b/drivers/mmc/core/mmcpstore.c new file mode 100644 index 000000000000..e394acc07c33 --- /dev/null +++ b/drivers/mmc/core/mmcpstore.c @@ -0,0 +1,232 @@ +// 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; + +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; + + 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); + + 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; + struct mmc_card *card = cxt->card; + int ret; + + /* Drop the panic record if parition switching is required */ + if (mmc_card_mmc(card) && mmc_blk_needs_part_switch(card)) + return -EPERM; + + ret = mmcpstore_panic_write_req(buf, sects, cxt->start_sect + off); + if (ret) + return ret; + + return 0; +} + +static struct block_device *mmcpstore_open_backend(const char *device) +{ + struct block_device *bdev; + dev_t devt; + + 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); + + bdev = blkdev_get_by_dev(devt, FMODE_READ, NULL); + if (IS_ERR(bdev)) + return bdev; + } + + return bdev; +} + +static void mmcpstore_close_backend(struct block_device *bdev) +{ + if (!bdev) + return; + blkdev_put(bdev, FMODE_READ); +} + +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; + + ret = pstore_blk_get_config(conf); + if (!conf->device[0]) { + pr_debug("psblk backend is empty\n"); + return; + } + + /* Multiple backend devices not allowed */ + if (cxt->dev_name[0]) + return; + + 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; + } + + bdevname(bdev, cxt->dev_name); + cxt->partno = bdev->bd_part->partno; + mmcpstore_close_backend(bdev); + + if (strncmp(cxt->dev_name, disk_name, strlen(disk_name))) + return; + + 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; + } + + /* Check for host mmc panic write polling function definitions */ + if (!card->host->ops->req_cleanup_pending || + !card->host->ops->req_completion_poll) + return; + + cxt->card = card; + + mrq = kzalloc(sizeof(struct mmc_request), GFP_KERNEL); + if (!mrq) + goto out; + + cmd = kzalloc(sizeof(struct mmc_command), GFP_KERNEL); + if (!cmd) + goto free_mrq; + + stop = kzalloc(sizeof(struct mmc_command), GFP_KERNEL); + if (!stop) + goto free_cmd; + + data = kzalloc(sizeof(struct mmc_data), GFP_KERNEL); + if (!data) + goto free_stop; + + mrq->cmd = cmd; + mrq->data = data; + mrq->stop = stop; + cxt->mrq = mrq; + + 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; + } + + pr_info("%s registered as psblk backend\n", cxt->dev_name); + return; + +free_data: + kfree(data); +free_stop: + kfree(stop); +free_cmd: + kfree(cmd); +free_mrq: + kfree(mrq); +out: + return; +} + +void unregister_mmcpstore(void) +{ + struct mmcpstore_context *cxt = &oops_cxt; + + unregister_pstore_blk(MMC_BLOCK_MAJOR); + kfree(cxt->mrq->data); + kfree(cxt->mrq->stop); + kfree(cxt->mrq->cmd); + kfree(cxt->mrq); + cxt->card = NULL; +} |