Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933268AbaLBUu6 (ORCPT ); Tue, 2 Dec 2014 15:50:58 -0500 Received: from mail-ig0-f176.google.com ([209.85.213.176]:39650 "EHLO mail-ig0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932894AbaLBUu0 (ORCPT ); Tue, 2 Dec 2014 15:50:26 -0500 From: Doug Anderson To: Jaehoon Chung , Seungwon Jeon , Ulf Hansson Cc: Alim Akhtar , Sonny Rao , Andrew Bresticker , Heiko Stuebner , Doug Anderson , chris@printf.net, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 2/3] mmc: dw_mmc: Cleanup disable of low power mode w/ SDIO interrupts Date: Tue, 2 Dec 2014 12:49:56 -0800 Message-Id: <1417553397-460-3-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.2.0.rc0.207.ga3a616c In-Reply-To: <1417553397-460-1-git-send-email-dianders@chromium.org> References: <1417553397-460-1-git-send-email-dianders@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the patch (9623b5b mmc: dw_mmc: Disable low power mode if SDIO interrupts are used) I added code that disabled the low power mode of dw_mmc when SDIO interrupts are used. That code worked but always felt a little hacky because we ended up disabling low power as a side effect of the first enable_sdio_irq() call. That wouldn't be so bad except that disabling low power involves a complicated process of writing to the CMD/CMDARG registers and that extra process makes it difficult to cleanly the read-modify-write race in dw_mci_enable_sdio_irq() (see future patch in the series). Change the code to take advantage of the init_card() callback of the mmc core to do this right at bootup. Signed-off-by: Doug Anderson --- Changes in v3: None Changes in v2: - Fixed "|" to "&". drivers/mmc/host/dw_mmc.c | 69 ++++++++++++++++++++++++----------------------- drivers/mmc/host/dw_mmc.h | 1 + 2 files changed, 36 insertions(+), 34 deletions(-) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 67c0451..ae10a02 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -926,7 +927,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit) /* enable clock; only low power if no SDIO */ clk_en_a = SDMMC_CLKEN_ENABLE << slot->id; - if (!(mci_readl(host, INTMASK) & SDMMC_INT_SDIO(slot->sdio_id))) + if (!test_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags)) clk_en_a |= SDMMC_CLKEN_LOW_PWR << slot->id; mci_writel(host, CLKENA, clk_en_a); @@ -1245,27 +1246,37 @@ static int dw_mci_get_cd(struct mmc_host *mmc) return present; } -/* - * Disable lower power mode. - * - * Low power mode will stop the card clock when idle. According to the - * description of the CLKENA register we should disable low power mode - * for SDIO cards if we need SDIO interrupts to work. - * - * This function is fast if low power mode is already disabled. - */ -static void dw_mci_disable_low_power(struct dw_mci_slot *slot) +static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card) { + struct dw_mci_slot *slot = mmc_priv(mmc); struct dw_mci *host = slot->host; - u32 clk_en_a; - const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id; - clk_en_a = mci_readl(host, CLKENA); + /* + * Low power mode will stop the card clock when idle. According to the + * description of the CLKENA register we should disable low power mode + * for SDIO cards if we need SDIO interrupts to work. + */ + if (mmc->caps & MMC_CAP_SDIO_IRQ) { + const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id; + u32 clk_en_a_old; + u32 clk_en_a; - if (clk_en_a & clken_low_pwr) { - mci_writel(host, CLKENA, clk_en_a & ~clken_low_pwr); - mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | - SDMMC_CMD_PRV_DAT_WAIT, 0); + clk_en_a_old = mci_readl(host, CLKENA); + + if (card->type == MMC_TYPE_SDIO || + card->type == MMC_TYPE_SD_COMBO) { + set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); + clk_en_a = clk_en_a_old & ~clken_low_pwr; + } else { + clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags); + clk_en_a = clk_en_a_old | clken_low_pwr; + } + + if (clk_en_a != clk_en_a_old) { + mci_writel(host, CLKENA, clk_en_a); + mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | + SDMMC_CMD_PRV_DAT_WAIT, 0); + } } } @@ -1277,21 +1288,11 @@ static void dw_mci_enable_sdio_irq(struct mmc_host *mmc, int enb) /* Enable/disable Slot Specific SDIO interrupt */ int_mask = mci_readl(host, INTMASK); - if (enb) { - /* - * Turn off low power mode if it was enabled. This is a bit of - * a heavy operation and we disable / enable IRQs a lot, so - * we'll leave low power mode disabled and it will get - * re-enabled again in dw_mci_setup_bus(). - */ - dw_mci_disable_low_power(slot); - - mci_writel(host, INTMASK, - (int_mask | SDMMC_INT_SDIO(slot->sdio_id))); - } else { - mci_writel(host, INTMASK, - (int_mask & ~SDMMC_INT_SDIO(slot->sdio_id))); - } + if (enb) + int_mask |= SDMMC_INT_SDIO(slot->sdio_id); + else + int_mask &= ~SDMMC_INT_SDIO(slot->sdio_id); + mci_writel(host, INTMASK, int_mask); } static int dw_mci_execute_tuning(struct mmc_host *mmc, u32 opcode) @@ -1337,7 +1338,7 @@ static const struct mmc_host_ops dw_mci_ops = { .execute_tuning = dw_mci_execute_tuning, .card_busy = dw_mci_card_busy, .start_signal_voltage_switch = dw_mci_switch_voltage, - + .init_card = dw_mci_init_card, }; static void dw_mci_request_end(struct dw_mci *host, struct mmc_request *mrq) diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h index 0d0f7a2..d27d4c0 100644 --- a/drivers/mmc/host/dw_mmc.h +++ b/drivers/mmc/host/dw_mmc.h @@ -244,6 +244,7 @@ struct dw_mci_slot { unsigned long flags; #define DW_MMC_CARD_PRESENT 0 #define DW_MMC_CARD_NEED_INIT 1 +#define DW_MMC_CARD_NO_LOW_PWR 2 int id; int sdio_id; }; -- 2.2.0.rc0.207.ga3a616c -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/