sdhci: handle data interrupts during command

It is fully legal for a controller to start issuing data related
interrupts before it has signalled that the command has completed.
Make sure the driver actually can handle this.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

drivers/mmc/host/sdhci.c

@@ -385,6 +385,9 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
 	BUG_ON(data->blksz > host->mmc->max_blk_size);
 	BUG_ON(data->blocks > 65535);
 
+	host->data = data;
+	host->data_early = 0;
+
 	/* timeout in us */
 	target_timeout = data->timeout_ns / 1000 +
 		data->timeout_clks / host->clock;
@@ -443,11 +446,11 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
 {
 	u16 mode;
 
-	WARN_ON(host->data);
-
 	if (data == NULL)
 		return;
 
+	WARN_ON(!host->data);
+
 	mode = SDHCI_TRNS_BLK_CNT_EN;
 	if (data->blocks > 1)
 		mode |= SDHCI_TRNS_MULTI;
@@ -600,9 +603,10 @@ static void sdhci_finish_command(struct sdhci_host *host)
 
 	host->cmd->error = MMC_ERR_NONE;
 
-	if (host->cmd->data)
-		host->data = host->cmd->data;
-	else
+	if (host->data && host->data_early)
+		sdhci_finish_data(host);
+
+	if (!host->cmd->data)
 		tasklet_schedule(&host->finish_tasklet);
 
 	host->cmd = NULL;
@@ -991,9 +995,19 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
 			writel(readl(host->ioaddr + SDHCI_DMA_ADDRESS),
 				host->ioaddr + SDHCI_DMA_ADDRESS);
 
-		if (intmask & SDHCI_INT_DATA_END)
+		if (intmask & SDHCI_INT_DATA_END) {
+			if (host->cmd) {
+				/*
+				 * Data managed to finish before the
+				 * command completed. Make sure we do
+				 * things in the proper order.
+				 */
+				host->data_early = 1;
+			} else {
 				sdhci_finish_data(host);
 			}
+		}
+	}
 }
 
 static irqreturn_t sdhci_irq(int irq, void *dev_id)

drivers/mmc/host/sdhci.h

@@ -182,6 +182,7 @@ struct sdhci_host {
 	struct mmc_request	*mrq;		/* Current request */
 	struct mmc_command	*cmd;		/* Current command */
 	struct mmc_data		*data;		/* Current data request */
+	int			data_early:1;	/* Data finished before cmd */
 
 	struct scatterlist	*cur_sg;	/* We're working on this */
 	int			num_sg;		/* Entries left */