From 2b8ac062f33781edbefb482c6abebfde6b373eed Mon Sep 17 00:00:00 2001 From: Vincent Whitchurch Date: Thu, 1 Jul 2021 10:05:34 +0200 Subject: [PATCH] mmc: dw_mmc: Add data CRC error injection This driver has had problems when handling data errors. Add fault injection support so that the abort handling can be easily triggered and regression-tested. A hrtimer is used to indicate a data CRC error at various points during the data transfer. Note that for the recent problem with hangs in the case of some data CRC errors, a udelay(10) inserted at the start of send_stop_abort() greatly helped in triggering the error, but I've not included this as part of the fault injection support since it seemed too specific. Signed-off-by: Vincent Whitchurch Reviewed-by: Jaehoon Chung Link: https://lore.kernel.org/r/20210701080534.23138-1-vincent.whitchurch@axis.com Signed-off-by: Ulf Hansson --- drivers/mmc/host/dw_mmc.c | 73 +++++++++++++++++++++++++++++++++++++++ drivers/mmc/host/dw_mmc.h | 7 ++++ 2 files changed, 80 insertions(+) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index c3229d8c7041..29c848e25df6 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -17,9 +17,11 @@ #include #include #include +#include #include #include #include +#include #include #include #include @@ -181,6 +183,9 @@ static void dw_mci_init_debugfs(struct dw_mci_slot *slot) &host->pending_events); debugfs_create_xul("completed_events", S_IRUSR, root, &host->completed_events); +#ifdef CONFIG_FAULT_INJECTION + fault_create_debugfs_attr("fail_data_crc", root, &host->fail_data_crc); +#endif } #endif /* defined(CONFIG_DEBUG_FS) */ @@ -1788,6 +1793,68 @@ static const struct mmc_host_ops dw_mci_ops = { .prepare_hs400_tuning = dw_mci_prepare_hs400_tuning, }; +#ifdef CONFIG_FAULT_INJECTION +static enum hrtimer_restart dw_mci_fault_timer(struct hrtimer *t) +{ + struct dw_mci *host = container_of(t, struct dw_mci, fault_timer); + unsigned long flags; + + spin_lock_irqsave(&host->irq_lock, flags); + + if (!host->data_status) + host->data_status = SDMMC_INT_DCRC; + set_bit(EVENT_DATA_ERROR, &host->pending_events); + tasklet_schedule(&host->tasklet); + + spin_unlock_irqrestore(&host->irq_lock, flags); + + return HRTIMER_NORESTART; +} + +static void dw_mci_start_fault_timer(struct dw_mci *host) +{ + struct mmc_data *data = host->data; + + if (!data || data->blocks <= 1) + return; + + if (!should_fail(&host->fail_data_crc, 1)) + return; + + /* + * Try to inject the error at random points during the data transfer. + */ + hrtimer_start(&host->fault_timer, + ms_to_ktime(prandom_u32() % 25), + HRTIMER_MODE_REL); +} + +static void dw_mci_stop_fault_timer(struct dw_mci *host) +{ + hrtimer_cancel(&host->fault_timer); +} + +static void dw_mci_init_fault(struct dw_mci *host) +{ + host->fail_data_crc = (struct fault_attr) FAULT_ATTR_INITIALIZER; + + hrtimer_init(&host->fault_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + host->fault_timer.function = dw_mci_fault_timer; +} +#else +static void dw_mci_init_fault(struct dw_mci *host) +{ +} + +static void dw_mci_start_fault_timer(struct dw_mci *host) +{ +} + +static void dw_mci_stop_fault_timer(struct dw_mci *host) +{ +} +#endif + static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq) __releases(&host->lock) __acquires(&host->lock) @@ -2102,6 +2169,7 @@ static void dw_mci_tasklet_func(struct tasklet_struct *t) break; } + dw_mci_stop_fault_timer(host); host->data = NULL; set_bit(EVENT_DATA_COMPLETE, &host->completed_events); err = dw_mci_data_complete(host, data); @@ -2151,6 +2219,7 @@ static void dw_mci_tasklet_func(struct tasklet_struct *t) if (mrq->cmd->error && mrq->data) dw_mci_reset(host); + dw_mci_stop_fault_timer(host); host->cmd = NULL; host->data = NULL; @@ -2600,6 +2669,8 @@ static void dw_mci_cmd_interrupt(struct dw_mci *host, u32 status) set_bit(EVENT_CMD_COMPLETE, &host->pending_events); tasklet_schedule(&host->tasklet); + + dw_mci_start_fault_timer(host); } static void dw_mci_handle_cd(struct dw_mci *host) @@ -3223,6 +3294,8 @@ int dw_mci_probe(struct dw_mci *host) spin_lock_init(&host->irq_lock); INIT_LIST_HEAD(&host->queue); + dw_mci_init_fault(host); + /* * Get the host data width - this assumes that HCON has been set with * the correct values. diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h index da5923a92e60..ce05d81477d9 100644 --- a/drivers/mmc/host/dw_mmc.h +++ b/drivers/mmc/host/dw_mmc.h @@ -14,6 +14,8 @@ #include #include #include +#include +#include #include enum dw_mci_state { @@ -230,6 +232,11 @@ struct dw_mci { struct timer_list cmd11_timer; struct timer_list cto_timer; struct timer_list dto_timer; + +#ifdef CONFIG_FAULT_INJECTION + struct fault_attr fail_data_crc; + struct hrtimer fault_timer; +#endif }; /* DMA ops for Internal/External DMAC interface */