Add support for setting a maximum DMA latency via the PM QOS framework. Drivers can set host->dma_latency to the desired value otherwise the initial value (PM_QOS_DEFAULT_VALUE) will result in no PM QOS request being added.
It may be that there isn't time between consecutive I/O requests to reach deeper C-states. To address that the driver can set host->lat_cancel_delay which is the delay before cancelling the DMA latency request when it is known that there is another request on the way. Signed-off-by: Adrian Hunter <[email protected]> --- drivers/mmc/host/sdhci.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ drivers/mmc/host/sdhci.h | 7 +++++++ 2 files changed, 59 insertions(+) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index d8be0bf..3a0859b 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -724,6 +724,45 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd) } } +static bool sdhci_pm_qos_use_dma_latency(struct sdhci_host *host) +{ + return host->dma_latency != PM_QOS_DEFAULT_VALUE; +} + +static void sdhci_pm_qos_set_dma_latency(struct sdhci_host *host, + struct mmc_request *mrq) +{ + if (sdhci_pm_qos_use_dma_latency(host) && mrq->data && + (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA))) { + pm_qos_update_request(&host->pm_qos_req, host->dma_latency); + host->pm_qos_set = true; + } +} + +static void sdhci_pm_qos_unset(struct sdhci_host *host) +{ + unsigned int delay; + + if (host->pm_qos_set) { + host->pm_qos_set = false; + delay = host->consecutive_req ? host->lat_cancel_delay : 0; + pm_qos_cancel_request_lazy(&host->pm_qos_req, delay); + } +} + +static void sdhci_pm_qos_add(struct sdhci_host *host) +{ + if (sdhci_pm_qos_use_dma_latency(host)) + pm_qos_add_request(&host->pm_qos_req, PM_QOS_CPU_DMA_LATENCY, + PM_QOS_DEFAULT_VALUE); +} + +static void sdhci_pm_qos_remove(struct sdhci_host *host) +{ + if (pm_qos_request_active(&host->pm_qos_req)) + pm_qos_remove_request(&host->pm_qos_req); +} + static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd) { u8 ctrl; @@ -1348,6 +1387,8 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq) err = mmc_retune(mmc); + sdhci_pm_qos_set_dma_latency(host, mrq); + /* Firstly check card presence */ present = sdhci_do_get_cd(host); @@ -1371,6 +1412,7 @@ static void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq) } host->mrq = mrq; + host->consecutive_req = 0; if (!err && (!present || host->flags & SDHCI_DEVICE_DEAD)) err = -ENOMEDIUM; @@ -2167,6 +2209,8 @@ static void sdhci_pre_req(struct mmc_host *mmc, struct mmc_request *mrq, { struct sdhci_host *host = mmc_priv(mmc); + host->consecutive_req = 1; + if (mrq->data->host_cookie) { mrq->data->host_cookie = 0; return; @@ -2243,6 +2287,8 @@ static void sdhci_tasklet_finish(unsigned long param) host = (struct sdhci_host*)param; + sdhci_pm_qos_unset(host); + spin_lock_irqsave(&host->lock, flags); /* @@ -2877,6 +2923,7 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev, host = mmc_priv(mmc); host->mmc = mmc; + host->dma_latency = PM_QOS_DEFAULT_VALUE; return host; } @@ -3363,6 +3410,8 @@ int sdhci_add_host(struct sdhci_host *host) */ mmc->max_blk_count = (host->quirks & SDHCI_QUIRK_NO_MULTIBLOCK) ? 1 : 65535; + sdhci_pm_qos_add(host); + /* * Init tasklets. */ @@ -3426,6 +3475,7 @@ reset: #endif untasklet: tasklet_kill(&host->finish_tasklet); + sdhci_pm_qos_remove(host); return ret; } @@ -3482,6 +3532,8 @@ void sdhci_remove_host(struct sdhci_host *host, int dead) host->adma_table = NULL; host->align_buffer = NULL; + + sdhci_pm_qos_remove(host); } EXPORT_SYMBOL_GPL(sdhci_remove_host); diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 5521d29..15c5e7b 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -19,6 +19,7 @@ #include <linux/io.h> #include <linux/mmc/host.h> +#include <linux/pm_qos.h> /* * Controller registers @@ -419,6 +420,12 @@ struct sdhci_host { struct mmc_host *mmc; /* MMC structure */ u64 dma_mask; /* custom DMA mask */ + struct pm_qos_request pm_qos_req; + int dma_latency; + int lat_cancel_delay; + int consecutive_req; + bool pm_qos_set; + #if defined(CONFIG_LEDS_CLASS) || defined(CONFIG_LEDS_CLASS_MODULE) struct led_classdev led; /* LED control */ char led_name[32]; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
