diff options
| author | Adrian Hunter <adrian.hunter@intel.com> | 2013-04-04 17:41:06 +0400 |
|---|---|---|
| committer | Chris Ball <cjb@laptop.org> | 2013-04-12 22:08:07 +0400 |
| commit | 0d3e3350d5871c53464be4c92d57198744247005 (patch) | |
| tree | cca13f8eb12a397c4ea8adf9f74de3bcd7c89041 | |
| parent | f9a94e0a3f18ae4c0245d4a16d0ee20e93fd7bad (diff) | |
| download | linux-0d3e3350d5871c53464be4c92d57198744247005.tar.xz | |
mmc: core: fix performance regression initializing MMC host controllers
Commit fa5501890d8974301042e0202d342a6cbe8609f4 introduced a performance
regression by adding mmc_power_up() to mmc_start_host(). mmc_power_up()
is not necessary to host controller initialization, it is part of card
initialization and is performed anyway asynchronously.
This patch allows a driver to leave the power up in asynchronous code
(as it was before).
On my current target platform this reduces driver initialization from:
[ 1.313220] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 102008 usecs
to this:
[ 1.217209] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 8331 usecs
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
| -rw-r--r-- | drivers/mmc/core/core.c | 3 | ||||
| -rw-r--r-- | drivers/mmc/host/sdhci-acpi.c | 2 | ||||
| -rw-r--r-- | include/linux/mmc/host.h | 1 |
3 files changed, 5 insertions, 1 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 3bf1c462eded..c1893c9c3c31 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2416,7 +2416,8 @@ void mmc_start_host(struct mmc_host *host) { host->f_init = max(freqs[0], host->f_min); host->rescan_disable = 0; - mmc_power_up(host); + if (!(host->caps2 & MMC_CAP2_NO_PRESCAN_POWERUP)) + mmc_power_up(host); mmc_detect_change(host, 0); } diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c index 2592dddbd965..7bcf74b1a5cd 100644 --- a/drivers/mmc/host/sdhci-acpi.c +++ b/drivers/mmc/host/sdhci-acpi.c @@ -195,6 +195,8 @@ static int sdhci_acpi_probe(struct platform_device *pdev) host->mmc->pm_caps |= c->slot->pm_caps; } + host->mmc->caps2 |= MMC_CAP2_NO_PRESCAN_POWERUP; + err = sdhci_add_host(host); if (err) goto err_free; diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 17d714801e94..8873e8349597 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -280,6 +280,7 @@ struct mmc_host { #define MMC_CAP2_PACKED_WR (1 << 13) /* Allow packed write */ #define MMC_CAP2_PACKED_CMD (MMC_CAP2_PACKED_RD | \ MMC_CAP2_PACKED_WR) +#define MMC_CAP2_NO_PRESCAN_POWERUP (1 << 14) /* Don't power up before scan */ mmc_pm_flag_t pm_caps; /* supported pm features */ |