mmc: bcm2835: Make sure the controller is idle after a request

Some situations like sending MMC_SEND_EXT_CSD command to a SD card
seems to confuse the controller / driver. The command fails before
the controller FSM is finished. So add this band-aid to make sure
the controller is idle before accepting new requests.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>

drivers/mmc/host/bcm2835.c

@@ -296,8 +296,12 @@ static void bcm2835_wait_transfer_complete(struct bcm2835_host *host)
 	int timediff;
 	u32 alternate_idle;
 
-	alternate_idle = (host->mrq->data->flags & MMC_DATA_READ) ?
-		SDEDM_FSM_READWAIT : SDEDM_FSM_WRITESTART1;
+	alternate_idle = SDEDM_FSM_IDENTMODE;
+
+	if (host->mrq->data) {
+		alternate_idle = (host->mrq->data->flags & MMC_DATA_READ) ?
+				 SDEDM_FSM_READWAIT : SDEDM_FSM_WRITESTART1;
+	}
 
 	timediff = 0;
 
@@ -322,7 +326,8 @@ static void bcm2835_wait_transfer_complete(struct bcm2835_host *host)
 				"wait_transfer_complete - still waiting after %d retries\n",
 				timediff);
 			bcm2835_dumpregs(host);
-			host->mrq->data->error = -ETIMEDOUT;
+			if (host->mrq->data)
+				host->mrq->data->error = -ETIMEDOUT;
 			return;
 		}
 		cpu_relax();
@@ -605,29 +610,42 @@ static u32 bcm2835_read_wait_sdcmd(struct bcm2835_host *host, u32 max_ms)
 
 static void bcm2835_finish_request(struct bcm2835_host *host)
 {
-	struct dma_chan *terminate_chan = NULL;
 	struct mmc_request *mrq;
+	u32 edm, fsm;
 
 	cancel_delayed_work_sync(&host->timeout_work);
 
+	if (host->dma_chan) {
+		int err = dmaengine_terminate_sync(host->dma_chan);
+
+		if (err)
+			dev_err(&host->pdev->dev,
+				"failed to terminate DMA (%d)\n", err);
+	}
+
+	/*
+	 * Some situations like sending MMC_SEND_EXT_CSD command to a SD card
+	 * seems to confuse the controller / driver. The command fails before
+	 * the controller FSM is finished. So make sure the FSM is idle.
+	 */
+	edm = readl(host->ioaddr + SDEDM);
+	fsm = edm & SDEDM_FSM_MASK;
+
+	if ((fsm != SDEDM_FSM_IDENTMODE) &&
+	    (fsm != SDEDM_FSM_DATAMODE))
+		dev_err(&host->pdev->dev, "FSM still busy\n");
+
+	bcm2835_wait_transfer_complete(host);
+
 	mrq = host->mrq;
 
 	host->mrq = NULL;
 	host->cmd = NULL;
 	host->data = NULL;
 
 	host->dma_desc = NULL;
-	terminate_chan = host->dma_chan;
 	host->dma_chan = NULL;
 
-	if (terminate_chan) {
-		int err = dmaengine_terminate_all(terminate_chan);
-
-		if (err)
-			dev_err(&host->pdev->dev,
-				"failed to terminate DMA (%d)\n", err);
-	}
-
 	mmc_request_done(host->mmc, mrq);
 }