s3cmci: make SDIO IRQ hardware IRQ support build-time configurable

We have found a couple of boards where the SDIO IRQ hardware support has
failed to work properly, and thus we should make it configurable whether
or not to be included in the driver.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/mmc/host/Kconfig

@@ -276,6 +276,13 @@ config MMC_S3C
 
 	  If unsure, say N.
 
+config MMC_S3C_HW_SDIO_IRQ
+       bool "Hardware support for SDIO IRQ"
+       depends on MMC_S3C
+       help
+         Enable the hardware support for SDIO interrupts instead of using
+	 the generic polling code.
+
 choice
 	prompt "Samsung S3C SD/MMC transfer code"
 	depends on MMC_S3C

drivers/mmc/host/s3cmci.c

@@ -1715,7 +1715,11 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
 
 	mmc->ops 	= &s3cmci_ops;
 	mmc->ocr_avail	= MMC_VDD_32_33 | MMC_VDD_33_34;
+#ifdef CONFIG_MMC_S3C_HW_SDIO_IRQ
 	mmc->caps	= MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;
+#else
+	mmc->caps	= MMC_CAP_4_BIT_DATA;
+#endif
 	mmc->f_min 	= host->clk_rate / (host->clk_div * 256);
 	mmc->f_max 	= host->clk_rate / host->clk_div;
 
@@ -1750,8 +1754,9 @@ static int __devinit s3cmci_probe(struct platform_device *pdev)
 	s3cmci_debugfs_attach(host);
 
 	platform_set_drvdata(pdev, mmc);
-	dev_info(&pdev->dev, "%s - using %s\n", mmc_hostname(mmc),
-		 s3cmci_host_usedma(host) ? "dma" : "pio");
+	dev_info(&pdev->dev, "%s - using %s, %s SDIO IRQ\n", mmc_hostname(mmc),
+		 s3cmci_host_usedma(host) ? "dma" : "pio",
+		 mmc->caps & MMC_CAP_SDIO_IRQ ? "hw" : "sw");
 
 	return 0;