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From: Ulf Hansson <ulf.hansson@stericsson.com>
To: linux-mmc@vger.kernel.org, Chris Ball <cjb@laptop.org>
Cc: linux-arm-kernel@lists.infradead.org,
	Russell King <linux@arm.linux.org.uk>,
	Linus Walleij <linus.walleij@linaro.org>,
	Ulf Hansson <ulf.hansson@stericsson.com>,
	Ulf Hansson <ulf.hansson@linaro.org>
Subject: [PATCH 2/2] mmc: mmci: Switching off HWFC for SDIO depends on MCLK
Date: Wed, 10 Oct 2012 17:43:45 +0200	[thread overview]
Message-ID: <1349883825-22517-2-git-send-email-ulf.hansson@stericsson.com> (raw)
In-Reply-To: <1349883825-22517-1-git-send-email-ulf.hansson@stericsson.com>

For writes, HWFC shall be switched off when transfer size <= 8
bytes and when MCLK rate is above 50 MHz. For 50MHz and below
it shall be switched off when transfer size < 8 bytes.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/host/mmci.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 877079e..cd0fbee 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -664,12 +664,14 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
 			datactrl |= MCI_ST_DPSM_SDIOEN;
 
 			/*
-			 * The ST Micro variant for SDIO transfer sizes
-			 * less then 8 bytes should have clock H/W flow
-			 * control disabled.
+			 * The ST Micro variant for SDIO small write transfers
+			 * needs to have clock H/W flow control disabled,
+			 * otherwise the transfer will not start. The threshold
+			 * depends on the rate of MCLK.
 			 */
-			if ((host->size < 8) &&
-			    (data->flags & MMC_DATA_WRITE))
+			if (data->flags & MMC_DATA_WRITE &&
+			    (host->size < 8 ||
+			     (host->size <= 8 && host->mclk > 50000000)))
 				clk = host->clk_reg & ~variant->clkreg_enable;
 			else
 				clk = host->clk_reg | variant->clkreg_enable;
-- 
1.7.10


WARNING: multiple messages have this Message-ID (diff)
From: ulf.hansson@stericsson.com (Ulf Hansson)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] mmc: mmci: Switching off HWFC for SDIO depends on MCLK
Date: Wed, 10 Oct 2012 17:43:45 +0200	[thread overview]
Message-ID: <1349883825-22517-2-git-send-email-ulf.hansson@stericsson.com> (raw)
In-Reply-To: <1349883825-22517-1-git-send-email-ulf.hansson@stericsson.com>

For writes, HWFC shall be switched off when transfer size <= 8
bytes and when MCLK rate is above 50 MHz. For 50MHz and below
it shall be switched off when transfer size < 8 bytes.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/host/mmci.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 877079e..cd0fbee 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -664,12 +664,14 @@ static void mmci_start_data(struct mmci_host *host, struct mmc_data *data)
 			datactrl |= MCI_ST_DPSM_SDIOEN;
 
 			/*
-			 * The ST Micro variant for SDIO transfer sizes
-			 * less then 8 bytes should have clock H/W flow
-			 * control disabled.
+			 * The ST Micro variant for SDIO small write transfers
+			 * needs to have clock H/W flow control disabled,
+			 * otherwise the transfer will not start. The threshold
+			 * depends on the rate of MCLK.
 			 */
-			if ((host->size < 8) &&
-			    (data->flags & MMC_DATA_WRITE))
+			if (data->flags & MMC_DATA_WRITE &&
+			    (host->size < 8 ||
+			     (host->size <= 8 && host->mclk > 50000000)))
 				clk = host->clk_reg & ~variant->clkreg_enable;
 			else
 				clk = host->clk_reg | variant->clkreg_enable;
-- 
1.7.10

  reply	other threads:[~2012-10-10 15:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-10 15:43 [PATCH 1/2] mmc: mmci: Fix incorrect handling of HW flow control for SDIO Ulf Hansson
2012-10-10 15:43 ` Ulf Hansson
2012-10-10 15:43 ` Ulf Hansson [this message]
2012-10-10 15:43   ` [PATCH 2/2] mmc: mmci: Switching off HWFC for SDIO depends on MCLK Ulf Hansson

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