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From b802bfd3bb337e92226bd521f8ebbbcfc6642333 Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Sun, 12 May 2013 12:25:52 +0100
Subject: [PATCH 021/196] sdhci-bcm2708: use extension FIFO to buffer DMA
transfers
The additional FIFO might speed up transfers in some cases.
---
drivers/mmc/host/sdhci-bcm2708.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/mmc/host/sdhci-bcm2708.c b/drivers/mmc/host/sdhci-bcm2708.c
index 3792b9f..326b962 100644
--- a/drivers/mmc/host/sdhci-bcm2708.c
+++ b/drivers/mmc/host/sdhci-bcm2708.c
@@ -74,6 +74,9 @@
/* Mhz clock that the EMMC core is running at. Should match the platform clockman settings */
#define BCM2708_EMMC_CLOCK_FREQ 50000000
+#define REG_EXRDFIFO_EN 0x80
+#define REG_EXRDFIFO_CFG 0x84
+
/*****************************************************************************\
* *
* Debug *
@@ -957,10 +960,12 @@ static ssize_t attr_dma_store(struct device *_dev,
int on = simple_strtol(buf, NULL, 0);
if (on) {
host->flags |= SDHCI_USE_PLATDMA;
+ sdhci_bcm2708_writel(host, 1, REG_EXRDFIFO_EN);
printk(KERN_INFO "%s: DMA enabled\n",
mmc_hostname(host->mmc));
} else {
host->flags &= ~(SDHCI_USE_PLATDMA | SDHCI_REQ_USE_DMA);
+ sdhci_bcm2708_writel(host, 0, REG_EXRDFIFO_EN);
printk(KERN_INFO "%s: DMA disabled\n",
mmc_hostname(host->mmc));
}
@@ -1272,6 +1277,12 @@ static int sdhci_bcm2708_probe(struct platform_device *pdev)
ret = device_create_file(&pdev->dev, &dev_attr_dma_wait);
ret = device_create_file(&pdev->dev, &dev_attr_status);
+#ifdef CONFIG_MMC_SDHCI_BCM2708_DMA
+ /* enable extension fifo for paced DMA transfers */
+ sdhci_bcm2708_writel(host, 1, REG_EXRDFIFO_EN);
+ sdhci_bcm2708_writel(host, 4, REG_EXRDFIFO_CFG);
+#endif
+
printk(KERN_INFO "%s: BCM2708 SDHC host at 0x%08llx DMA %d IRQ %d\n",
mmc_hostname(host->mmc), (unsigned long long)iomem->start,
host_priv->dma_chan, host_priv->dma_irq);
--
1.9.1
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