linux-kernel - [PATCH] OMAP: HSMMC: Do not enable buffer ready interrupt if using DMA

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Date:	Tue, 21 Apr 2009 13:09:22 +0530
From:	"Gadiyar, Anand" <gadiyar@...com>
To:	"pierre@...man.eu" <pierre@...man.eu>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>
Subject: [PATCH] OMAP: HSMMC: Do not enable buffer ready interrupt if using
 DMA

From: Anand Gadiyar <gadiyar@...com>

OMAP: HSMMC: Do not enable buffer ready interrupt if using DMA

This considerably reduces the number of interrupts during a transfer
and ought to result in some power saving.

Signed-off-by: Anand Gadiyar <gadiyar@...com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@...com>
Acked-by: Kishore Kadiyala <kishore.kadiyala@...com>
---
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index e62a22a..2d83807 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -70,6 +70,8 @@
 #define DTO_MASK		0x000F0000
 #define DTO_SHIFT		16
 #define INT_EN_MASK		0x307F0033
+#define BWR_ENABLE		(1 << 4)
+#define BRR_ENABLE		(1 << 5)
 #define INIT_STREAM		(1 << 1)
 #define DP_SELECT		(1 << 21)
 #define DDIR			(1 << 4)
@@ -241,7 +243,12 @@ mmc_omap_start_command(struct mmc_omap_host *host, struct mmc_command *cmd,
 	 */
 	OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
 	OMAP_HSMMC_WRITE(host->base, ISE, INT_EN_MASK);
-	OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
+
+	if (host->use_dma)
+		OMAP_HSMMC_WRITE(host->base, IE,
+				 INT_EN_MASK & ~(BRR_ENABLE | BWR_ENABLE));
+	else
+		OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
 
 	host->response_busy = 0;
 	if (cmd->flags & MMC_RSP_PRESENT) {
--
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