Previously there has only been one function mmc_wait_for_req() to start and wait for a request. This patch adds * mmc_start_req() - starts a request wihtout waiting If there is on ongoing request wait for completion of that request and start the new one and return. Does not wait for the new command to complete.

This patch also adds new function members in struct mmc_host_ops only called from core.c * pre_req - asks the host driver to prepare for the next job * post_req - asks the host driver to clean up after a completed job

The intention is to use pre_req() and post_req() to do cache maintenance while a request is active. pre_req() can be called while a request is active to minimize latency to start next job. post_req() can be used after the next job is started to clean up the request. This will minimize the host driver request end latency. post_req() is typically used before ending the block request and handing over the buffer to the block layer.

Add a host-private member in mmc_data to be used by pre_req to mark the data. The host driver will then check this mark to see if the data is prepared or not.

Signed-off-by: Per Forlin per.forlin@linaro.org --- drivers/mmc/core/core.c | 111 +++++++++++++++++++++++++++++++++++++++++---- include/linux/mmc/core.h | 6 ++- include/linux/mmc/host.h | 16 +++++++ 3 files changed, 122 insertions(+), 11 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 1f453ac..66e1403 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -198,10 +198,108 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)

static void mmc_wait_done(struct mmc_request *mrq) { - complete(mrq->done_data); + complete(&mrq->completion); +} + +static void __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq) +{ + init_completion(&mrq->completion); + mrq->done = mmc_wait_done; + mmc_start_request(host, mrq); +} + +static void mmc_wait_for_req_done(struct mmc_host *host, + struct mmc_request *mrq) +{ + wait_for_completion(&mrq->completion); +} + +/** + * mmc_pre_req - Prepare for a new request + * @host: MMC host to prepare command + * @mrq: MMC request to prepare for + * @is_first_req: true if there is no previous started request + * that may run in parellel to this call, otherwise false + * + * mmc_pre_req() is called in prior to mmc_start_req() to let + * host prepare for the new request. Preparation of a request may be + * performed while another request is running on the host. + */ +static void mmc_pre_req(struct mmc_host *host, struct mmc_request *mrq, + bool is_first_req) +{ + if (host->ops->pre_req) + host->ops->pre_req(host, mrq, is_first_req); }

/** + * mmc_post_req - Post process a completed request + * @host: MMC host to post process command + * @mrq: MMC request to post process for + * @err: Error, if none zero, clean up any resources made in pre_req + * + * Let the host post process a completed request. Post processing of + * a request may be performed while another reuqest is running. + */ +static void mmc_post_req(struct mmc_host *host, struct mmc_request *mrq, + int err) +{ + if (host->ops->post_req) + host->ops->post_req(host, mrq, err); +} + +/** + * mmc_start_req - start a none blocking request + * @host: MMC host to start command + * @areq: async request to start + * @error: none zero in case of error + * + * Start a new MMC custom command request for a host. + * If there is on ongoing async request wait for completion + * of that request and start the new one and return. + * Does not wait for the new request to complete. + * + * Returns the completed async request, NULL in case of none completed. + */ +struct mmc_async_req *mmc_start_req(struct mmc_host *host, + struct mmc_async_req *areq, int *error) +{ + int err = 0; + struct mmc_async_req *data = host->areq; + + /* Prepare a new request */ + if (areq) + mmc_pre_req(host, areq->mrq, !host->areq); + + if (host->areq) { + mmc_wait_for_req_done(host, host->areq->mrq); + err = host->areq->err_check(host->card, host->areq); + if (err) { + mmc_post_req(host, host->areq->mrq, 0); + if (areq) + mmc_post_req(host, areq->mrq, -EINVAL); + + host->areq = NULL; + if (error) + *error = err; + return data; + } + } + + if (areq) + __mmc_start_req(host, areq->mrq); + + if (host->areq) + mmc_post_req(host, host->areq->mrq, 0); + + host->areq = areq; + if (error) + *error = err; + return data; +} +EXPORT_SYMBOL(mmc_start_req); + +/** * mmc_wait_for_req - start a request and wait for completion * @host: MMC host to start command * @mrq: MMC request to start @@ -212,16 +310,9 @@ static void mmc_wait_done(struct mmc_request *mrq) */ void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq) { - DECLARE_COMPLETION_ONSTACK(complete); - - mrq->done_data = &complete; - mrq->done = mmc_wait_done; - - mmc_start_request(host, mrq); - - wait_for_completion(&complete); + __mmc_start_req(host, mrq); + mmc_wait_for_req_done(host, mrq); } - EXPORT_SYMBOL(mmc_wait_for_req);

/** diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h index 07f27af..28b5956 100644 --- a/include/linux/mmc/core.h +++ b/include/linux/mmc/core.h @@ -117,6 +117,7 @@ struct mmc_data {

unsigned int sg_len; /* size of scatter list */ struct scatterlist *sg; /* I/O scatter list */ + s32 host_cookie; /* host private data */ };

struct mmc_request { @@ -124,13 +125,16 @@ struct mmc_request { struct mmc_data *data; struct mmc_command *stop;

- void *done_data; /* completion data */ + struct completion completion; void (*done)(struct mmc_request *);/* completion function */ };

struct mmc_host; struct mmc_card; +struct mmc_async_req;

+extern struct mmc_async_req *mmc_start_req(struct mmc_host *, + struct mmc_async_req *, int *); extern void mmc_wait_for_req(struct mmc_host *, struct mmc_request *); extern int mmc_wait_for_cmd(struct mmc_host *, struct mmc_command *, int); extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *, diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index eb792cb..d2d948b 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -88,6 +88,15 @@ struct mmc_host_ops { */ int (*enable)(struct mmc_host *host); int (*disable)(struct mmc_host *host, int lazy); + /* + * It is optional for the host to implement pre_req and post_req in + * order to support double buffering of requests (prepare one + * request while another request is active). + */ + void (*post_req)(struct mmc_host *host, struct mmc_request *req, + int err); + void (*pre_req)(struct mmc_host *host, struct mmc_request *req, + bool is_first_req); void (*request)(struct mmc_host *host, struct mmc_request *req); /* * Avoid calling these three functions too often or in a "fast path", @@ -122,6 +131,11 @@ struct mmc_host_ops { struct mmc_card; struct device;

+struct mmc_async_req { + struct mmc_request *mrq; + int (*err_check) (struct mmc_card *, struct mmc_async_req *); +}; + struct mmc_host { struct device *parent; struct device class_dev; @@ -242,6 +256,8 @@ struct mmc_host {

struct dentry *debugfs_root;

+ struct mmc_async_req *areq; /* active async req */ + unsigned long private[0] ____cacheline_aligned; };

pre_req() runs dma_map_sg(), post_req() runs dma_unmap_sg. If not calling pre_req() before omap_hsmmc_request() dma_map_sg will be issued before starting the transfer. It is optional to use pre_req(). If issuing pre_req() post_req() must be to be called as well.

Signed-off-by: Per Forlin per.forlin@linaro.org --- drivers/mmc/host/omap_hsmmc.c | 87 +++++++++++++++++++++++++++++++++++++++-- 1 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c index ad3731a..2116c09 100644 --- a/drivers/mmc/host/omap_hsmmc.c +++ b/drivers/mmc/host/omap_hsmmc.c @@ -141,6 +141,11 @@ #define OMAP_HSMMC_WRITE(base, reg, val) \ __raw_writel((val), (base) + OMAP_HSMMC_##reg)

+struct omap_hsmmc_next { + unsigned int dma_len; + s32 cookie; +}; + struct omap_hsmmc_host { struct device *dev; struct mmc_host *mmc; @@ -184,6 +189,7 @@ struct omap_hsmmc_host { int reqs_blocked; int use_reg; int req_in_progress; + struct omap_hsmmc_next next_data;

struct omap_mmc_platform_data *pdata; }; @@ -1344,8 +1350,9 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data) return; }

- dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, - omap_hsmmc_get_dma_dir(host, data)); + if (!data->host_cookie) + dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, + omap_hsmmc_get_dma_dir(host, data));

req_in_progress = host->req_in_progress; dma_ch = host->dma_ch; @@ -1363,6 +1370,45 @@ static void omap_hsmmc_dma_cb(int lch, u16 ch_status, void *cb_data) } }

+static int omap_hsmmc_pre_dma_transfer(struct omap_hsmmc_host *host, + struct mmc_data *data, + struct omap_hsmmc_next *next) +{ + int dma_len; + + if (!next && data->host_cookie && + data->host_cookie != host->next_data.cookie) { + printk(KERN_WARNING "[%s] invalid cookie: data->host_cookie %d" + " host->next_data.cookie %d\n", + __func__, data->host_cookie, host->next_data.cookie); + data->host_cookie = 0; + } + + /* Check if next job is already prepared */ + if (next || + (!next && data->host_cookie != host->next_data.cookie)) { + dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, + data->sg_len, + omap_hsmmc_get_dma_dir(host, data)); + + } else { + dma_len = host->next_data.dma_len; + host->next_data.dma_len = 0; + } + + + if (dma_len == 0) + return -EINVAL; + + if (next) { + next->dma_len = dma_len; + data->host_cookie = ++next->cookie < 0 ? 1 : next->cookie; + } else + host->dma_len = dma_len; + + return 0; +} + /* * Routine to configure and start DMA for the MMC card */ @@ -1396,9 +1442,10 @@ static int omap_hsmmc_start_dma_transfer(struct omap_hsmmc_host *host, mmc_hostname(host->mmc), ret); return ret; } + ret = omap_hsmmc_pre_dma_transfer(host, data, NULL); + if (ret) + return ret;

- host->dma_len = dma_map_sg(mmc_dev(host->mmc), data->sg, - data->sg_len, omap_hsmmc_get_dma_dir(host, data)); host->dma_ch = dma_ch; host->dma_sg_idx = 0;

@@ -1478,6 +1525,35 @@ omap_hsmmc_prepare_data(struct omap_hsmmc_host *host, struct mmc_request *req) return 0; }

+static void omap_hsmmc_post_req(struct mmc_host *mmc, struct mmc_request *mrq, + int err) +{ + struct omap_hsmmc_host *host = mmc_priv(mmc); + struct mmc_data *data = mrq->data; + + if (host->use_dma) { + dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len, + omap_hsmmc_get_dma_dir(host, data)); + data->host_cookie = 0; + } +} + +static void omap_hsmmc_pre_req(struct mmc_host *mmc, struct mmc_request *mrq, + bool is_first_req) +{ + struct omap_hsmmc_host *host = mmc_priv(mmc); + + if (mrq->data->host_cookie) { + mrq->data->host_cookie = 0; + return ; + } + + if (host->use_dma) + if (omap_hsmmc_pre_dma_transfer(host, mrq->data, + &host->next_data)) + mrq->data->host_cookie = 0; +} + /* * Request function. for read/write operation */ @@ -1926,6 +2002,8 @@ static int omap_hsmmc_disable_fclk(struct mmc_host *mmc, int lazy) static const struct mmc_host_ops omap_hsmmc_ops = { .enable = omap_hsmmc_enable_fclk, .disable = omap_hsmmc_disable_fclk, + .post_req = omap_hsmmc_post_req, + .pre_req = omap_hsmmc_pre_req, .request = omap_hsmmc_request, .set_ios = omap_hsmmc_set_ios, .get_cd = omap_hsmmc_get_cd, @@ -2075,6 +2153,7 @@ static int __init omap_hsmmc_probe(struct platform_device *pdev) host->mapbase = res->start; host->base = ioremap(host->mapbase, SZ_4K); host->power_mode = MMC_POWER_OFF; + host->next_data.cookie = 1;

platform_set_drvdata(pdev, host); INIT_WORK(&host->mmc_carddetect_work, omap_hsmmc_detect);

Add a debugfs file "testlist" to print all available tests

Signed-off-by: Per Forlin per.forlin@linaro.org --- drivers/mmc/card/mmc_test.c | 39 ++++++++++++++++++++++++++++++++++++++- 1 files changed, 38 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c index abc1a63..1853ebf 100644 --- a/drivers/mmc/card/mmc_test.c +++ b/drivers/mmc/card/mmc_test.c @@ -2447,6 +2447,32 @@ static const struct file_operations mmc_test_fops_test = { .release = single_release, };

+static int mtf_testlist_show(struct seq_file *sf, void *data) +{ + int i; + + mutex_lock(&mmc_test_lock); + + for (i = 0; i < ARRAY_SIZE(mmc_test_cases); i++) + seq_printf(sf, "%d:\t%s\n", i+1, mmc_test_cases[i].name); + + mutex_unlock(&mmc_test_lock); + + return 0; +} + +static int mtf_testlist_open(struct inode *inode, struct file *file) +{ + return single_open(file, mtf_testlist_show, inode->i_private); +} + +static const struct file_operations mmc_test_fops_testlist = { + .open = mtf_testlist_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + static void mmc_test_free_file_test(struct mmc_card *card) { struct mmc_test_dbgfs_file *df, *dfs; @@ -2478,7 +2504,18 @@ static int mmc_test_register_file_test(struct mmc_card *card)

if (IS_ERR_OR_NULL(file)) { dev_err(&card->dev, - "Can't create file. Perhaps debugfs is disabled.\n"); + "Can't create test. Perhaps debugfs is disabled.\n"); + ret = -ENODEV; + goto err; + } + + if (card->debugfs_root) + file = debugfs_create_file("testlist", S_IRUGO, + card->debugfs_root, card, &mmc_test_fops_testlist); + + if (IS_ERR_OR_NULL(file)) { + dev_err(&card->dev, + "Can't create testlist. Perhaps debugfs is disabled.\n"); ret = -ENODEV; goto err; }

The way the request data is organized in the mmc queue struct it only allows processing of one request at the time. This patch adds a new struct to hold mmc queue request data such as sg list, request, blk request and bounce buffers, and updates any functions depending on the mmc queue struct. This lies the ground for using multiple active request for one mmc queue.

Signed-off-by: Per Forlin per.forlin@linaro.org --- drivers/mmc/card/block.c | 106 ++++++++++++++++++-------------------- drivers/mmc/card/queue.c | 129 ++++++++++++++++++++++++---------------------- drivers/mmc/card/queue.h | 30 ++++++++--- 3 files changed, 139 insertions(+), 126 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 61d233a..c45c436 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -165,13 +165,6 @@ static const struct block_device_operations mmc_bdops = { .owner = THIS_MODULE, };

-struct mmc_blk_request { - struct mmc_request mrq; - struct mmc_command cmd; - struct mmc_command stop; - struct mmc_data data; -}; - static u32 mmc_sd_num_wr_blocks(struct mmc_card *card) { int err; @@ -335,7 +328,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) { struct mmc_blk_data *md = mq->data; struct mmc_card *card = md->queue.card; - struct mmc_blk_request brq; + struct mmc_blk_request *brq = &mq->mqrq_cur->brq; int ret = 1, disable_multi = 0;

mmc_claim_host(card->host); @@ -344,72 +337,72 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) struct mmc_command cmd; u32 readcmd, writecmd, status = 0;

- memset(&brq, 0, sizeof(struct mmc_blk_request)); - brq.mrq.cmd = &brq.cmd; - brq.mrq.data = &brq.data; + memset(brq, 0, sizeof(struct mmc_blk_request)); + brq->mrq.cmd = &brq->cmd; + brq->mrq.data = &brq->data;

- brq.cmd.arg = blk_rq_pos(req); + brq->cmd.arg = blk_rq_pos(req); if (!mmc_card_blockaddr(card)) - brq.cmd.arg <<= 9; - brq.cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC; - brq.data.blksz = 512; - brq.stop.opcode = MMC_STOP_TRANSMISSION; - brq.stop.arg = 0; - brq.stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC; - brq.data.blocks = blk_rq_sectors(req); + brq->cmd.arg <<= 9; + brq->cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC; + brq->data.blksz = 512; + brq->stop.opcode = MMC_STOP_TRANSMISSION; + brq->stop.arg = 0; + brq->stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC; + brq->data.blocks = blk_rq_sectors(req);

/* * The block layer doesn't support all sector count * restrictions, so we need to be prepared for too big * requests. */ - if (brq.data.blocks > card->host->max_blk_count) - brq.data.blocks = card->host->max_blk_count; + if (brq->data.blocks > card->host->max_blk_count) + brq->data.blocks = card->host->max_blk_count;

/* * After a read error, we redo the request one sector at a time * in order to accurately determine which sectors can be read * successfully. */ - if (disable_multi && brq.data.blocks > 1) - brq.data.blocks = 1; + if (disable_multi && brq->data.blocks > 1) + brq->data.blocks = 1;

- if (brq.data.blocks > 1) { + if (brq->data.blocks > 1) { /* SPI multiblock writes terminate using a special * token, not a STOP_TRANSMISSION request. */ if (!mmc_host_is_spi(card->host) || rq_data_dir(req) == READ) - brq.mrq.stop = &brq.stop; + brq->mrq.stop = &brq->stop; readcmd = MMC_READ_MULTIPLE_BLOCK; writecmd = MMC_WRITE_MULTIPLE_BLOCK; } else { - brq.mrq.stop = NULL; + brq->mrq.stop = NULL; readcmd = MMC_READ_SINGLE_BLOCK; writecmd = MMC_WRITE_BLOCK; } if (rq_data_dir(req) == READ) { - brq.cmd.opcode = readcmd; - brq.data.flags |= MMC_DATA_READ; + brq->cmd.opcode = readcmd; + brq->data.flags |= MMC_DATA_READ; } else { - brq.cmd.opcode = writecmd; - brq.data.flags |= MMC_DATA_WRITE; + brq->cmd.opcode = writecmd; + brq->data.flags |= MMC_DATA_WRITE; }

- mmc_set_data_timeout(&brq.data, card); + mmc_set_data_timeout(&brq->data, card);

- brq.data.sg = mq->sg; - brq.data.sg_len = mmc_queue_map_sg(mq); + brq->data.sg = mq->mqrq_cur->sg; + brq->data.sg_len = mmc_queue_map_sg(mq, mq->mqrq_cur);

/* * Adjust the sg list so it is the same size as the * request. */ - if (brq.data.blocks != blk_rq_sectors(req)) { - int i, data_size = brq.data.blocks << 9; + if (brq->data.blocks != blk_rq_sectors(req)) { + int i, data_size = brq->data.blocks << 9; struct scatterlist *sg;

- for_each_sg(brq.data.sg, sg, brq.data.sg_len, i) { + for_each_sg(brq->data.sg, sg, brq->data.sg_len, i) { data_size -= sg->length; if (data_size <= 0) { sg->length += data_size; @@ -417,22 +410,22 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) break; } } - brq.data.sg_len = i; + brq->data.sg_len = i; }

- mmc_queue_bounce_pre(mq); + mmc_queue_bounce_pre(mq->mqrq_cur);

- mmc_wait_for_req(card->host, &brq.mrq); + mmc_wait_for_req(card->host, &brq->mrq);

- mmc_queue_bounce_post(mq); + mmc_queue_bounce_post(mq->mqrq_cur);

/* * Check for errors here, but don't jump to cmd_err * until later as we need to wait for the card to leave * programming mode even when things go wrong. */ - if (brq.cmd.error || brq.data.error || brq.stop.error) { - if (brq.data.blocks > 1 && rq_data_dir(req) == READ) { + if (brq->cmd.error || brq->data.error || brq->stop.error) { + if (brq->data.blocks > 1 && rq_data_dir(req) == READ) { /* Redo read one sector at a time */ printk(KERN_WARNING "%s: retrying using single " "block read\n", req->rq_disk->disk_name); @@ -442,29 +435,29 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) status = get_card_status(card, req); }

- if (brq.cmd.error) { + if (brq->cmd.error) { printk(KERN_ERR "%s: error %d sending read/write " "command, response %#x, card status %#x\n", - req->rq_disk->disk_name, brq.cmd.error, - brq.cmd.resp[0], status); + req->rq_disk->disk_name, brq->cmd.error, + brq->cmd.resp[0], status); }

- if (brq.data.error) { - if (brq.data.error == -ETIMEDOUT && brq.mrq.stop) + if (brq->data.error) { + if (brq->data.error == -ETIMEDOUT && brq->mrq.stop) /* 'Stop' response contains card status */ - status = brq.mrq.stop->resp[0]; + status = brq->mrq.stop->resp[0]; printk(KERN_ERR "%s: error %d transferring data," " sector %u, nr %u, card status %#x\n", - req->rq_disk->disk_name, brq.data.error, + req->rq_disk->disk_name, brq->data.error, (unsigned)blk_rq_pos(req), (unsigned)blk_rq_sectors(req), status); }

- if (brq.stop.error) { + if (brq->stop.error) { printk(KERN_ERR "%s: error %d sending stop command, " "response %#x, card status %#x\n", - req->rq_disk->disk_name, brq.stop.error, - brq.stop.resp[0], status); + req->rq_disk->disk_name, brq->stop.error, + brq->stop.resp[0], status); }

if (!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) { @@ -497,7 +490,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) #endif }

- if (brq.cmd.error || brq.stop.error || brq.data.error) { + if (brq->cmd.error || brq->stop.error || brq->data.error) { if (rq_data_dir(req) == READ) { /* * After an error, we redo I/O one sector at a @@ -505,7 +498,8 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) * read a single sector. */ spin_lock_irq(&md->lock); - ret = __blk_end_request(req, -EIO, brq.data.blksz); + ret = __blk_end_request(req, -EIO, + brq->data.blksz); spin_unlock_irq(&md->lock); continue; } @@ -516,7 +510,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) * A block was successfully transferred. */ spin_lock_irq(&md->lock); - ret = __blk_end_request(req, 0, brq.data.bytes_xfered); + ret = __blk_end_request(req, 0, brq->data.bytes_xfered); spin_unlock_irq(&md->lock); } while (ret);

@@ -544,7 +538,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) } } else { spin_lock_irq(&md->lock); - ret = __blk_end_request(req, 0, brq.data.bytes_xfered); + ret = __blk_end_request(req, 0, brq->data.bytes_xfered); spin_unlock_irq(&md->lock); }

diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c index 2ae7275..40e18b5 100644 --- a/drivers/mmc/card/queue.c +++ b/drivers/mmc/card/queue.c @@ -56,7 +56,7 @@ static int mmc_queue_thread(void *d) spin_lock_irq(q->queue_lock); set_current_state(TASK_INTERRUPTIBLE); req = blk_fetch_request(q); - mq->req = req; + mq->mqrq_cur->req = req; spin_unlock_irq(q->queue_lock);

if (!req) { @@ -97,10 +97,25 @@ static void mmc_request(struct request_queue *q) return; }

- if (!mq->req) + if (!mq->mqrq_cur->req) wake_up_process(mq->thread); }

+struct scatterlist *mmc_alloc_sg(int sg_len, int *err) +{ + struct scatterlist *sg; + + sg = kmalloc(sizeof(struct scatterlist)*sg_len, GFP_KERNEL); + if (!sg) + *err = -ENOMEM; + else { + *err = 0; + sg_init_table(sg, sg_len); + } + + return sg; +} + /** * mmc_init_queue - initialise a queue structure. * @mq: mmc queue @@ -114,6 +129,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock struct mmc_host *host = card->host; u64 limit = BLK_BOUNCE_HIGH; int ret; + struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];

if (mmc_dev(host)->dma_mask && *mmc_dev(host)->dma_mask) limit = *mmc_dev(host)->dma_mask; @@ -123,8 +139,9 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock if (!mq->queue) return -ENOMEM;

+ memset(&mq->mqrq_cur, 0, sizeof(mq->mqrq_cur)); + mq->mqrq_cur = mqrq_cur; mq->queue->queuedata = mq; - mq->req = NULL;

blk_queue_prep_rq(mq->queue, mmc_prep_request); queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue); @@ -158,53 +175,44 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock bouncesz = host->max_blk_count * 512;

if (bouncesz > 512) { - mq->bounce_buf = kmalloc(bouncesz, GFP_KERNEL); - if (!mq->bounce_buf) { + mqrq_cur->bounce_buf = kmalloc(bouncesz, GFP_KERNEL); + if (!mqrq_cur->bounce_buf) { printk(KERN_WARNING "%s: unable to " - "allocate bounce buffer\n", + "allocate bounce cur buffer\n", mmc_card_name(card)); } }

- if (mq->bounce_buf) { + if (mqrq_cur->bounce_buf) { blk_queue_bounce_limit(mq->queue, BLK_BOUNCE_ANY); blk_queue_max_hw_sectors(mq->queue, bouncesz / 512); blk_queue_max_segments(mq->queue, bouncesz / 512); blk_queue_max_segment_size(mq->queue, bouncesz);

- mq->sg = kmalloc(sizeof(struct scatterlist), - GFP_KERNEL); - if (!mq->sg) { - ret = -ENOMEM; + mqrq_cur->sg = mmc_alloc_sg(1, &ret); + if (ret) goto cleanup_queue; - } - sg_init_table(mq->sg, 1);

- mq->bounce_sg = kmalloc(sizeof(struct scatterlist) * - bouncesz / 512, GFP_KERNEL); - if (!mq->bounce_sg) { - ret = -ENOMEM; + mqrq_cur->bounce_sg = + mmc_alloc_sg(bouncesz / 512, &ret); + if (ret) goto cleanup_queue; - } - sg_init_table(mq->bounce_sg, bouncesz / 512); + } } #endif

- if (!mq->bounce_buf) { + if (!mqrq_cur->bounce_buf) { blk_queue_bounce_limit(mq->queue, limit); blk_queue_max_hw_sectors(mq->queue, min(host->max_blk_count, host->max_req_size / 512)); blk_queue_max_segments(mq->queue, host->max_segs); blk_queue_max_segment_size(mq->queue, host->max_seg_size);

- mq->sg = kmalloc(sizeof(struct scatterlist) * - host->max_segs, GFP_KERNEL); - if (!mq->sg) { - ret = -ENOMEM; + mqrq_cur->sg = mmc_alloc_sg(host->max_segs, &ret); + if (ret) goto cleanup_queue; - } - sg_init_table(mq->sg, host->max_segs); + }

sema_init(&mq->thread_sem, 1); @@ -219,16 +227,15 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock

return 0; free_bounce_sg: - if (mq->bounce_sg) - kfree(mq->bounce_sg); - mq->bounce_sg = NULL; + kfree(mqrq_cur->bounce_sg); + mqrq_cur->bounce_sg = NULL; + cleanup_queue: - if (mq->sg) - kfree(mq->sg); - mq->sg = NULL; - if (mq->bounce_buf) - kfree(mq->bounce_buf); - mq->bounce_buf = NULL; + kfree(mqrq_cur->sg); + mqrq_cur->sg = NULL; + kfree(mqrq_cur->bounce_buf); + mqrq_cur->bounce_buf = NULL; + blk_cleanup_queue(mq->queue); return ret; } @@ -237,6 +244,7 @@ void mmc_cleanup_queue(struct mmc_queue *mq) { struct request_queue *q = mq->queue; unsigned long flags; + struct mmc_queue_req *mqrq_cur = mq->mqrq_cur;

/* Make sure the queue isn't suspended, as that will deadlock */ mmc_queue_resume(mq); @@ -250,16 +258,14 @@ void mmc_cleanup_queue(struct mmc_queue *mq) blk_start_queue(q); spin_unlock_irqrestore(q->queue_lock, flags);

- if (mq->bounce_sg) - kfree(mq->bounce_sg); - mq->bounce_sg = NULL; + kfree(mqrq_cur->bounce_sg); + mqrq_cur->bounce_sg = NULL;

- kfree(mq->sg); - mq->sg = NULL; + kfree(mqrq_cur->sg); + mqrq_cur->sg = NULL;

- if (mq->bounce_buf) - kfree(mq->bounce_buf); - mq->bounce_buf = NULL; + kfree(mqrq_cur->bounce_buf); + mqrq_cur->bounce_buf = NULL;

mq->card = NULL; } @@ -312,27 +318,27 @@ void mmc_queue_resume(struct mmc_queue *mq) /* * Prepare the sg list(s) to be handed of to the host driver */ -unsigned int mmc_queue_map_sg(struct mmc_queue *mq) +unsigned int mmc_queue_map_sg(struct mmc_queue *mq, struct mmc_queue_req *mqrq) { unsigned int sg_len; size_t buflen; struct scatterlist *sg; int i;

- if (!mq->bounce_buf) - return blk_rq_map_sg(mq->queue, mq->req, mq->sg); + if (!mqrq->bounce_buf) + return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);

- BUG_ON(!mq->bounce_sg); + BUG_ON(!mqrq->bounce_sg);

- sg_len = blk_rq_map_sg(mq->queue, mq->req, mq->bounce_sg); + sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);

- mq->bounce_sg_len = sg_len; + mqrq->bounce_sg_len = sg_len;

buflen = 0; - for_each_sg(mq->bounce_sg, sg, sg_len, i) + for_each_sg(mqrq->bounce_sg, sg, sg_len, i) buflen += sg->length;

- sg_init_one(mq->sg, mq->bounce_buf, buflen); + sg_init_one(mqrq->sg, mqrq->bounce_buf, buflen);

return 1; } @@ -341,19 +347,19 @@ unsigned int mmc_queue_map_sg(struct mmc_queue *mq) * If writing, bounce the data to the buffer before the request * is sent to the host driver */ -void mmc_queue_bounce_pre(struct mmc_queue *mq) +void mmc_queue_bounce_pre(struct mmc_queue_req *mqrq) { unsigned long flags;

- if (!mq->bounce_buf) + if (!mqrq->bounce_buf) return;

- if (rq_data_dir(mq->req) != WRITE) + if (rq_data_dir(mqrq->req) != WRITE) return;

local_irq_save(flags); - sg_copy_to_buffer(mq->bounce_sg, mq->bounce_sg_len, - mq->bounce_buf, mq->sg[0].length); + sg_copy_to_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len, + mqrq->bounce_buf, mqrq->sg[0].length); local_irq_restore(flags); }

@@ -361,19 +367,18 @@ void mmc_queue_bounce_pre(struct mmc_queue *mq) * If reading, bounce the data from the buffer after the request * has been handled by the host driver */ -void mmc_queue_bounce_post(struct mmc_queue *mq) +void mmc_queue_bounce_post(struct mmc_queue_req *mqrq) { unsigned long flags;

- if (!mq->bounce_buf) + if (!mqrq->bounce_buf) return;

- if (rq_data_dir(mq->req) != READ) + if (rq_data_dir(mqrq->req) != READ) return;

local_irq_save(flags); - sg_copy_from_buffer(mq->bounce_sg, mq->bounce_sg_len, - mq->bounce_buf, mq->sg[0].length); + sg_copy_from_buffer(mqrq->bounce_sg, mqrq->bounce_sg_len, + mqrq->bounce_buf, mqrq->sg[0].length); local_irq_restore(flags); } - diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h index 64e66e0..468044f 100644 --- a/drivers/mmc/card/queue.h +++ b/drivers/mmc/card/queue.h @@ -4,19 +4,32 @@ struct request; struct task_struct;

+struct mmc_blk_request { + struct mmc_request mrq; + struct mmc_command cmd; + struct mmc_command stop; + struct mmc_data data; +}; + +struct mmc_queue_req { + struct request *req; + struct mmc_blk_request brq; + struct scatterlist *sg; + char *bounce_buf; + struct scatterlist *bounce_sg; + unsigned int bounce_sg_len; +}; + struct mmc_queue { struct mmc_card *card; struct task_struct *thread; struct semaphore thread_sem; unsigned int flags; - struct request *req; int (*issue_fn)(struct mmc_queue *, struct request *); void *data; struct request_queue *queue; - struct scatterlist *sg; - char *bounce_buf; - struct scatterlist *bounce_sg; - unsigned int bounce_sg_len; + struct mmc_queue_req mqrq[1]; + struct mmc_queue_req *mqrq_cur; };

extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *, spinlock_t *); @@ -24,8 +37,9 @@ extern void mmc_cleanup_queue(struct mmc_queue *); extern void mmc_queue_suspend(struct mmc_queue *); extern void mmc_queue_resume(struct mmc_queue *);

-extern unsigned int mmc_queue_map_sg(struct mmc_queue *); -extern void mmc_queue_bounce_pre(struct mmc_queue *); -extern void mmc_queue_bounce_post(struct mmc_queue *); +extern unsigned int mmc_queue_map_sg(struct mmc_queue *, + struct mmc_queue_req *); +extern void mmc_queue_bounce_pre(struct mmc_queue_req *); +extern void mmc_queue_bounce_post(struct mmc_queue_req *);

#endif

Break out code without functional changes. This simplifies the code and makes way for handle two parallel request.

Signed-off-by: Per Forlin per.forlin@linaro.org --- drivers/mmc/card/block.c | 226 +++++++++++++++++++++++++++------------------- 1 files changed, 132 insertions(+), 94 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index aead2d1..1c0b077 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -79,6 +79,13 @@ struct mmc_blk_data {

static DEFINE_MUTEX(open_lock);

+enum mmc_blk_status { + MMC_BLK_SUCCESS = 0, + MMC_BLK_RETRY, + MMC_BLK_DATA_ERR, + MMC_BLK_CMD_ERR, +}; + module_param(perdev_minors, int, 0444); MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");

@@ -324,6 +331,102 @@ out: return err ? 0 : 1; }

+static enum mmc_blk_status mmc_blk_err_check(struct mmc_blk_request *brq, + struct request *req, + struct mmc_card *card, + struct mmc_blk_data *md) +{ + struct mmc_command cmd; + u32 status = 0; + enum mmc_blk_status ret = MMC_BLK_SUCCESS; + + /* + * Check for errors here, but don't jump to cmd_err + * until later as we need to wait for the card to leave + * programming mode even when things go wrong. + */ + if (brq->cmd.error || brq->data.error || brq->stop.error) { + if (brq->data.blocks > 1 && rq_data_dir(req) == READ) { + /* Redo read one sector at a time */ + printk(KERN_WARNING "%s: retrying using single " + "block read, brq %p\n", + req->rq_disk->disk_name, brq); + ret = MMC_BLK_RETRY; + goto out; + } + status = get_card_status(card, req); + } + + if (brq->cmd.error) { + printk(KERN_ERR "%s: error %d sending read/write " + "command, response %#x, card status %#x\n", + req->rq_disk->disk_name, brq->cmd.error, + brq->cmd.resp[0], status); + } + + if (brq->data.error) { + if (brq->data.error == -ETIMEDOUT && brq->mrq.stop) + /* 'Stop' response contains card status */ + status = brq->mrq.stop->resp[0]; + printk(KERN_ERR "%s: error %d transferring data," + " sector %u, nr %u, card status %#x\n", + req->rq_disk->disk_name, brq->data.error, + (unsigned)blk_rq_pos(req), + (unsigned)blk_rq_sectors(req), status); + } + + if (brq->stop.error) { + printk(KERN_ERR "%s: error %d sending stop command, " + "response %#x, card status %#x\n", + req->rq_disk->disk_name, brq->stop.error, + brq->stop.resp[0], status); + } + + if (!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) { + do { + int err; + + cmd.opcode = MMC_SEND_STATUS; + cmd.arg = card->rca << 16; + cmd.flags = MMC_RSP_R1 | MMC_CMD_AC; + err = mmc_wait_for_cmd(card->host, &cmd, 5); + if (err) { + printk(KERN_ERR "%s: error %d requesting status\n", + req->rq_disk->disk_name, err); + ret = MMC_BLK_CMD_ERR; + goto out; + } + /* + * Some cards mishandle the status bits, + * so make sure to check both the busy + * indication and the card state. + */ + } while (!(cmd.resp[0] & R1_READY_FOR_DATA) || + (R1_CURRENT_STATE(cmd.resp[0]) == 7)); + +#if 0 + if (cmd.resp[0] & ~0x00000900) + printk(KERN_ERR "%s: status = %08x\n", + req->rq_disk->disk_name, cmd.resp[0]); + if (mmc_decode_status(cmd.resp)) { + ret = MMC_BLK_CMD_ERR; + goto out; + } + +#endif + } + + if (brq->cmd.error || brq->stop.error || brq->data.error) { + if (rq_data_dir(req) == READ) + ret = MMC_BLK_DATA_ERR; + else + ret = MMC_BLK_CMD_ERR; + } + out: + return ret; + +} + static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq, struct mmc_card *card, int disable_multi, @@ -419,111 +522,46 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req) struct mmc_card *card = md->queue.card; struct mmc_blk_request *brq = &mq->mqrq_cur->brq; int ret = 1, disable_multi = 0; + enum mmc_blk_status status;

mmc_claim_host(card->host);

do { - struct mmc_command cmd; - u32 status = 0; - mmc_blk_rw_rq_prep(mq->mqrq_cur, card, disable_multi, mq); mmc_wait_for_req(card->host, &brq->mrq);

mmc_queue_bounce_post(mq->mqrq_cur); + status = mmc_blk_err_check(brq, req, card, md);

- /* - * Check for errors here, but don't jump to cmd_err - * until later as we need to wait for the card to leave - * programming mode even when things go wrong. - */ - if (brq->cmd.error || brq->data.error || brq->stop.error) { - if (brq->data.blocks > 1 && rq_data_dir(req) == READ) { - /* Redo read one sector at a time */ - printk(KERN_WARNING "%s: retrying using single " - "block read\n", req->rq_disk->disk_name); - disable_multi = 1; - continue; - } - status = get_card_status(card, req); - } - - if (brq->cmd.error) { - printk(KERN_ERR "%s: error %d sending read/write " - "command, response %#x, card status %#x\n", - req->rq_disk->disk_name, brq->cmd.error, - brq->cmd.resp[0], status); - } - - if (brq->data.error) { - if (brq->data.error == -ETIMEDOUT && brq->mrq.stop) - /* 'Stop' response contains card status */ - status = brq->mrq.stop->resp[0]; - printk(KERN_ERR "%s: error %d transferring data," - " sector %u, nr %u, card status %#x\n", - req->rq_disk->disk_name, brq->data.error, - (unsigned)blk_rq_pos(req), - (unsigned)blk_rq_sectors(req), status); - } - - if (brq->stop.error) { - printk(KERN_ERR "%s: error %d sending stop command, " - "response %#x, card status %#x\n", - req->rq_disk->disk_name, brq->stop.error, - brq->stop.resp[0], status); - } - - if (!mmc_host_is_spi(card->host) && rq_data_dir(req) != READ) { - do { - int err; - - cmd.opcode = MMC_SEND_STATUS; - cmd.arg = card->rca << 16; - cmd.flags = MMC_RSP_R1 | MMC_CMD_AC; - err = mmc_wait_for_cmd(card->host, &cmd, 5); - if (err) { - printk(KERN_ERR "%s: error %d requesting status\n", - req->rq_disk->disk_name, err); - goto cmd_err; - } - /* - * Some cards mishandle the status bits, - * so make sure to check both the busy - * indication and the card state. - */ - } while (!(cmd.resp[0] & R1_READY_FOR_DATA) || - (R1_CURRENT_STATE(cmd.resp[0]) == 7)); - -#if 0 - if (cmd.resp[0] & ~0x00000900) - printk(KERN_ERR "%s: status = %08x\n", - req->rq_disk->disk_name, cmd.resp[0]); - if (mmc_decode_status(cmd.resp)) - goto cmd_err; -#endif - } - - if (brq->cmd.error || brq->stop.error || brq->data.error) { - if (rq_data_dir(req) == READ) { - /* - * After an error, we redo I/O one sector at a - * time, so we only reach here after trying to - * read a single sector. - */ - spin_lock_irq(&md->lock); - ret = __blk_end_request(req, -EIO, - brq->data.blksz); - spin_unlock_irq(&md->lock); - continue; - } + switch (status) { + case MMC_BLK_CMD_ERR: goto cmd_err; - } + break; + case MMC_BLK_RETRY: + disable_multi = 1; + ret = 1; + break; + case MMC_BLK_DATA_ERR: + /* + * After an error, we redo I/O one sector at a + * time, so we only reach here after trying to + * read a single sector. + */ + spin_lock_irq(&md->lock); + ret = __blk_end_request(req, -EIO, + brq->data.blksz); + spin_unlock_irq(&md->lock);

- /* - * A block was successfully transferred. - */ - spin_lock_irq(&md->lock); - ret = __blk_end_request(req, 0, brq->data.bytes_xfered); - spin_unlock_irq(&md->lock); + break; + case MMC_BLK_SUCCESS: + /* + * A block was successfully transferred. + */ + spin_lock_irq(&md->lock); + ret = __blk_end_request(req, 0, brq->data.bytes_xfered); + spin_unlock_irq(&md->lock); + break; + } } while (ret);

mmc_release_host(card->host);

This simple fault injection proved to be very useful to test the error handling in the block.c rw_rq(). It may still be useful to test if the host driver handle pre_req() and post_req() correctly in case of errors.

Signed-off-by: Per Forlin per.forlin@linaro.org --- drivers/mmc/core/core.c | 54 ++++++++++++++++++++++++++++++++++++++++++++ drivers/mmc/core/debugfs.c | 5 ++++ include/linux/mmc/host.h | 3 ++ lib/Kconfig.debug | 11 +++++++++ 4 files changed, 73 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 66e1403..51d1cbe 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -23,6 +23,8 @@ #include <linux/log2.h> #include <linux/regulator/consumer.h> #include <linux/pm_runtime.h> +#include <linux/fault-inject.h> +#include <linux/random.h>

#include <linux/mmc/card.h> #include <linux/mmc/host.h> @@ -82,6 +84,56 @@ static void mmc_flush_scheduled_work(void) flush_workqueue(workqueue); }

+#ifdef CONFIG_FAIL_MMC_REQUEST + +static DECLARE_FAULT_ATTR(fail_mmc_request); + +static int __init setup_fail_mmc_request(char *str) +{ + return setup_fault_attr(&fail_mmc_request, str); +} +__setup("fail_mmc_request=", setup_fail_mmc_request); + +static void mmc_should_fail_request(struct mmc_host *host, + struct mmc_request *mrq) +{ + struct mmc_command *cmd = mrq->cmd; + struct mmc_data *data = mrq->data; + static const int data_errors[] = { + -ETIMEDOUT, + -EILSEQ, + -EIO, + }; + + if (!data) + return; + + if (cmd->error || data->error || !host->make_it_fail || + !should_fail(&fail_mmc_request, data->blksz * data->blocks)) + return; + + data->error = data_errors[random32() % ARRAY_SIZE(data_errors)]; + data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9; +} + +static int __init fail_mmc_request_debugfs(void) +{ + return init_fault_attr_dentries(&fail_mmc_request, + "fail_mmc_request"); +} + +late_initcall(fail_mmc_request_debugfs); + +#else /* CONFIG_FAIL_MMC_REQUEST */ + +static void mmc_should_fail_request(struct mmc_host *host, + struct mmc_request *mrq) +{ +} + +#endif /* CONFIG_FAIL_MMC_REQUEST */ + + /** * mmc_request_done - finish processing an MMC request * @host: MMC host which completed request @@ -108,6 +160,8 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq) cmd->error = 0; host->ops->request(host, mrq); } else { + mmc_should_fail_request(host, mrq); + led_trigger_event(host->led, LED_OFF);

pr_debug("%s: req done (CMD%u): %d: %08x %08x %08x %08x\n", diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c index 998797e..588e76f 100644 --- a/drivers/mmc/core/debugfs.c +++ b/drivers/mmc/core/debugfs.c @@ -188,6 +188,11 @@ void mmc_add_host_debugfs(struct mmc_host *host) root, &host->clk_delay)) goto err_node; #endif +#ifdef CONFIG_FAIL_MMC_REQUEST + if (!debugfs_create_u8("make-it-fail", S_IRUSR | S_IWUSR, + root, &host->make_it_fail)) + goto err_node; +#endif return;

err_node: diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index d2d948b..25818ce 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -258,6 +258,9 @@ struct mmc_host {

struct mmc_async_req *areq; /* active async req */

+#ifdef CONFIG_FAIL_MMC_REQUEST + u8 make_it_fail; +#endif unsigned long private[0] ____cacheline_aligned; };

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c768bcd..330fc70 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1057,6 +1057,17 @@ config FAIL_IO_TIMEOUT Only works with drivers that use the generic timeout handling, for others it wont do anything.

+config FAIL_MMC_REQUEST + bool "Fault-injection capability for MMC IO" + select DEBUG_FS + depends on FAULT_INJECTION + help + Provide fault-injection capability for MMC IO. + This will make the mmc core return data errors. This is + useful for testing the error handling in the mmc block device + and how the mmc host driver handle retries from + the block device. + config FAULT_INJECTION_DEBUG_FS bool "Debugfs entries for fault-injection capabilities" depends on FAULT_INJECTION && SYSFS && DEBUG_FS