MMC: davinci: misc. driver cleanup

This patch will remove some un bounded loops in the PIO mode. Added
some comments in the code. Merged few functions for better
readability. This patch has been tested on DM6446 EVM.
Signed-off-by: Purushotam Kumar <purushotam@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

drivers/mmc/host/davinci_mmc.c

@@ -816,11 +816,23 @@ static void mmc_davinci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 	host->bus_mode = ios->bus_mode;
 	if (ios->power_mode == MMC_POWER_UP) {
+		unsigned long timeout = jiffies + msecs_to_jiffies(50);
+		bool lose = true;
+
 		/* Send clock cycles, poll completion */
 		writel(0, host->base + DAVINCI_MMCARGHL);
 		writel(MMCCMD_INITCK, host->base + DAVINCI_MMCCMD);
-		while (!(readl(host->base + DAVINCI_MMCST0) & MMCST0_RSPDNE))
+		while (time_before(jiffies, timeout)) {
+			u32 tmp = readl(host->base + DAVINCI_MMCST0);
+
+			if (tmp & MMCST0_RSPDNE) {
+				lose = false;
+				break;
+			}
 			cpu_relax();
+		}
+		if (lose)
+			dev_warn(mmc_dev(host->mmc), "powerup timeout\n");
 	}
 
 	/* FIXME on power OFF, reset things ... */
@@ -900,15 +912,33 @@ davinci_abort_data(struct mmc_davinci_host *host, struct mmc_data *data)
 	writel(temp, host->base + DAVINCI_MMCCTL);
 }
 
-static inline int handle_core_command(
-		struct mmc_davinci_host *host, unsigned int status)
+static irqreturn_t mmc_davinci_irq(int irq, void *dev_id)
 {
+	struct mmc_davinci_host *host = (struct mmc_davinci_host *)dev_id;
+	unsigned int status, qstatus;
 	int end_command = 0;
 	int end_transfer = 0;
-	unsigned int qstatus = status;
 	struct mmc_data *data = host->data;
 
-	/* handle FIFO first when using PIO for data */
+	if (host->cmd == NULL && host->data == NULL) {
+		status = readl(host->base + DAVINCI_MMCST0);
+		dev_dbg(mmc_dev(host->mmc),
+			"Spurious interrupt 0x%04x\n", status);
+		/* Disable the interrupt from mmcsd */
+		writel(0, host->base + DAVINCI_MMCIM);
+		return IRQ_NONE;
+	}
+
+	status = readl(host->base + DAVINCI_MMCST0);
+	qstatus = status;
+
+	/* handle FIFO first when using PIO for data.
+	 * bytes_left will decrease to zero as I/O progress and status will
+	 * read zero over iteration because this controller status
+	 * register(MMCST0) reports any status only once and it is cleared
+	 * by read. So, it is not unbouned loop even in the case of
+	 * non-dma.
+	 */
 	while (host->bytes_left && (status & (MMCST0_DXRDY | MMCST0_DRRDY))) {
 		davinci_fifo_data_trans(host, rw_threshold);
 		status = readl(host->base + DAVINCI_MMCST0);
@@ -1004,30 +1034,6 @@ static inline int handle_core_command(
 		mmc_davinci_cmd_done(host, host->cmd);
 	if (end_transfer)
 		mmc_davinci_xfer_done(host, data);
-	return 0;
-}
-
-static irqreturn_t mmc_davinci_irq(int irq, void *dev_id)
-{
-	struct mmc_davinci_host *host = (struct mmc_davinci_host *)dev_id;
-	unsigned int status;
-
-	if (host->cmd == NULL && host->data == NULL) {
-		status = readl(host->base + DAVINCI_MMCST0);
-		dev_dbg(mmc_dev(host->mmc),
-			"Spurious interrupt 0x%04x\n", status);
-		/* Disable the interrupt from mmcsd */
-		writel(0, host->base + DAVINCI_MMCIM);
-		return IRQ_HANDLED;
-	}
-
-	do {
-		status = readl(host->base + DAVINCI_MMCST0);
-		if (status == 0)
-			break;
-		if (handle_core_command(host, status))
-			break;
-	} while (1);
 	return IRQ_HANDLED;
 }