From 682696605c7093d2800c498c04166831e5aedf87 Mon Sep 17 00:00:00 2001 From: Ulf Hansson Date: Thu, 13 Apr 2017 16:48:11 +0200 Subject: [PATCH] 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(+) 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); -- 2.20.1