linux-kernel - [PATCH] sdhci: always use max timeout for xfers

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Message-ID: <D8739074-546D-4531-A8E9-23E9F7A33EB5@marvell.com>
Date:	Fri, 25 Feb 2011 09:54:35 -0800
From:	Philip Rakity <prakity@...vell.com>
To:	"linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>
CC:	Kyungmin Park <kyungmin.park@...sung.com>,
	Wolfram Sang <w.sang@...gutronix.de>,
	Jae hoon Chung <jh80.chung@...il.com>,
	Chuanxiao Dong <chuanxiao.dong@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH] sdhci: always use max timeout for xfers

Rather then special case busy etc .. lets just use the max value.  

Did not remove BROKEN_TIMEOUT QUIRK so existing code will compile
we can remove this once existing platform drivers delete usage and get
quirk back.

Patch starts after ====
=====

The card/host controller may sometimes return a value that is
too low and cause the h/w to timeout a transfer that would have
worked.  Using the maximum value avoids this.

Signed-off-by: Philip Rakity <prakity@...vell.com>
---
 drivers/mmc/host/sdhci.c |   48 ++++-----------------------------------------
 1 files changed, 5 insertions(+), 43 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 655617c..dd99da8 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -592,53 +592,15 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
 		data->sg_len, direction);
 }
 
-static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_data *data)
+static inline u8 sdhci_calc_timeout(void)
 {
-	u8 count;
-	unsigned target_timeout, current_timeout;
-
 	/*
-	 * If the host controller provides us with an incorrect timeout
-	 * value, just skip the check and use 0xE.  The hardware may take
+	 * The host controller/card can provide us with an incorrect timeout
+	 * value, just use the maximum value 0xE.  The hardware may take
 	 * longer to time out, but that's much better than having a too-short
 	 * timeout value.
 	 */
-	if (host->quirks & SDHCI_QUIRK_BROKEN_TIMEOUT_VAL)
-		return 0xE;
-
-	/* timeout in us */
-	target_timeout = data->timeout_ns / 1000 +
-		data->timeout_clks / host->clock;
-
-	if (host->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK)
-		host->timeout_clk = host->clock / 1000;
-
-	/*
-	 * Figure out needed cycles.
-	 * We do this in steps in order to fit inside a 32 bit int.
-	 * The first step is the minimum timeout, which will have a
-	 * minimum resolution of 6 bits:
-	 * (1) 2^13*1000 > 2^22,
-	 * (2) host->timeout_clk < 2^16
-	 *     =>
-	 *     (1) / (2) > 2^6
-	 */
-	count = 0;
-	current_timeout = (1 << 13) * 1000 / host->timeout_clk;
-	while (current_timeout < target_timeout) {
-		count++;
-		current_timeout <<= 1;
-		if (count >= 0xF)
-			break;
-	}
-
-	if (count >= 0xF) {
-		printk(KERN_WARNING "%s: Too large timeout requested!\n",
-			mmc_hostname(host->mmc));
-		count = 0xE;
-	}
-
-	return count;
+	return 0xE;
 }
 
 static void sdhci_set_transfer_irqs(struct sdhci_host *host)
@@ -671,7 +633,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
 	host->data = data;
 	host->data_early = 0;
 
-	count = sdhci_calc_timeout(host, data);
+	count = sdhci_calc_timeout();
 	sdhci_writeb(host, count, SDHCI_TIMEOUT_CONTROL);
 
 	if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA))
-- 
1.7.0.4

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