From e3a84267ab3184656929b4cbf03fca4d446125dd Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Wed, 19 Apr 2017 21:52:29 +0200 Subject: mmc: core: Prevent processing SDIO IRQs when none is claimed In cases when MMC_CAP2_SDIO_IRQ_NOTHREAD is set, there is a minor window for when the mmc host could call sdio_run_irqs(), while in fact an SDIO func driver could have decided to released the SDIO IRQ via a call to sdio_release_irq(). In this scenario, processing of the SDIO IRQs are done even if there is none IRQ claimed, which is not what we want. To prevent this from happen, close the window by validating that at least one SDIO IRQs is claimed, before deciding to process them. Signed-off-by: Ulf Hansson Tested-by: Douglas Anderson Reviewed-by: Douglas Anderson --- drivers/mmc/core/sdio_irq.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/mmc/core/sdio_irq.c') diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c index 6d4b72080d51..44d9c86bd2d4 100644 --- a/drivers/mmc/core/sdio_irq.c +++ b/drivers/mmc/core/sdio_irq.c @@ -95,8 +95,10 @@ static int process_sdio_pending_irqs(struct mmc_host *host) void sdio_run_irqs(struct mmc_host *host) { mmc_claim_host(host); - host->sdio_irq_pending = true; - process_sdio_pending_irqs(host); + if (host->sdio_irqs) { + host->sdio_irq_pending = true; + process_sdio_pending_irqs(host); + } mmc_release_host(host); } EXPORT_SYMBOL_GPL(sdio_run_irqs); -- cgit v1.2.3 From 682696605c7093d2800c498c04166831e5aedf87 Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Thu, 13 Apr 2017 16:48:11 +0200 Subject: mmc: sdio: Add API to manage SDIO IRQs from a workqueue For hosts not supporting MMC_CAP2_SDIO_IRQ_NOTHREAD but MMC_CAP_SDIO_IRQ, the SDIO IRQs are processed from a dedicated kernel thread. For these cases, the host calls mmc_signal_sdio_irq() from its ISR to signal a new SDIO IRQ. Signaling an SDIO IRQ makes the host's ->enable_sdio_irq() callback to be invoked to temporary disable the IRQs, before the kernel thread is woken up to process it. When processing of the IRQs are completed, they are re-enabled by the kernel thread, again via invoking the host's ->enable_sdio_irq(). The observation from this, is that the execution path is being unnecessary complex, as the host driver already knows that it needs to temporary disable the IRQs before signaling a new one. Moreover, replacing the kernel thread with a work/workqueue would not only greatly simplify the code, but also make it more robust. To address the above problems, let's continue to build upon the support for MMC_CAP2_SDIO_IRQ_NOTHREAD, as it already implements SDIO IRQs to be processed without using the clumsy kernel thread and without the ping-pong calls of the host's ->enable_sdio_irq() callback for each processed IRQ. Therefore, let's add new API sdio_signal_irq(), which enables hosts to signal/process SDIO IRQs by using a work/workqueue, rather than using the kernel thread. Add also a new host callback ->ack_sdio_irq(), which the work invokes when the SDIO IRQs have been processed. This informs the host about when it shall re-enable the SDIO IRQs. Potentially, we could re-use the existing ->enable_sdio_irq() callback instead of adding a new one, however it has turned out that it's more convenient for hosts to get this information via a separate callback. Hosts that wants to use this new method to signal/process SDIO IRQs, must enable MMC_CAP2_SDIO_IRQ_NOTHREAD and implement the ->ack_sdio_irq() callback. Signed-off-by: Ulf Hansson Tested-by: Douglas Anderson Reviewed-by: Douglas Anderson --- drivers/mmc/core/host.c | 2 ++ drivers/mmc/core/sdio_irq.c | 16 ++++++++++++++++ drivers/mmc/core/sdio_ops.h | 2 ++ include/linux/mmc/host.h | 3 +++ 4 files changed, 23 insertions(+) (limited to 'drivers/mmc/core/sdio_irq.c') diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 3f8c85d5aa09..8823c97a7b38 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -30,6 +30,7 @@ #include "host.h" #include "slot-gpio.h" #include "pwrseq.h" +#include "sdio_ops.h" #define cls_dev_to_mmc_host(d) container_of(d, struct mmc_host, class_dev) @@ -379,6 +380,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) spin_lock_init(&host->lock); init_waitqueue_head(&host->wq); INIT_DELAYED_WORK(&host->detect, mmc_rescan); + INIT_DELAYED_WORK(&host->sdio_irq_work, sdio_irq_work); setup_timer(&host->retune_timer, mmc_retune_timer, (unsigned long)host); /* diff --git a/drivers/mmc/core/sdio_irq.c b/drivers/mmc/core/sdio_irq.c index 44d9c86bd2d4..c771843e4c15 100644 --- a/drivers/mmc/core/sdio_irq.c +++ b/drivers/mmc/core/sdio_irq.c @@ -98,11 +98,27 @@ void sdio_run_irqs(struct mmc_host *host) if (host->sdio_irqs) { host->sdio_irq_pending = true; process_sdio_pending_irqs(host); + if (host->ops->ack_sdio_irq) + host->ops->ack_sdio_irq(host); } mmc_release_host(host); } EXPORT_SYMBOL_GPL(sdio_run_irqs); +void sdio_irq_work(struct work_struct *work) +{ + struct mmc_host *host = + container_of(work, struct mmc_host, sdio_irq_work.work); + + sdio_run_irqs(host); +} + +void sdio_signal_irq(struct mmc_host *host) +{ + queue_delayed_work(system_wq, &host->sdio_irq_work, 0); +} +EXPORT_SYMBOL_GPL(sdio_signal_irq); + static int sdio_irq_thread(void *_host) { struct mmc_host *host = _host; diff --git a/drivers/mmc/core/sdio_ops.h b/drivers/mmc/core/sdio_ops.h index ee35cb4d170e..96945cafbf0b 100644 --- a/drivers/mmc/core/sdio_ops.h +++ b/drivers/mmc/core/sdio_ops.h @@ -17,6 +17,7 @@ struct mmc_host; struct mmc_card; +struct work_struct; int mmc_send_io_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr); int mmc_io_rw_direct(struct mmc_card *card, int write, unsigned fn, @@ -25,6 +26,7 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn, unsigned addr, int incr_addr, u8 *buf, unsigned blocks, unsigned blksz); int sdio_reset(struct mmc_host *host); unsigned int mmc_align_data_size(struct mmc_card *card, unsigned int sz); +void sdio_irq_work(struct work_struct *work); static inline bool sdio_is_io_busy(u32 opcode, u32 arg) { diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 21385ac0c9b1..f186b26c05a4 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -130,6 +130,7 @@ struct mmc_host_ops { int (*get_cd)(struct mmc_host *host); void (*enable_sdio_irq)(struct mmc_host *host, int enable); + void (*ack_sdio_irq)(struct mmc_host *host); /* optional callback for HC quirks */ void (*init_card)(struct mmc_host *host, struct mmc_card *card); @@ -358,6 +359,7 @@ struct mmc_host { unsigned int sdio_irqs; struct task_struct *sdio_irq_thread; + struct delayed_work sdio_irq_work; bool sdio_irq_pending; atomic_t sdio_irq_thread_abort; @@ -428,6 +430,7 @@ static inline void mmc_signal_sdio_irq(struct mmc_host *host) } void sdio_run_irqs(struct mmc_host *host); +void sdio_signal_irq(struct mmc_host *host); #ifdef CONFIG_REGULATOR int mmc_regulator_get_ocrmask(struct regulator *supply); -- cgit v1.2.3