[V3] mmc: mmci: Fixup and cleanup code for DMA handling

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 1507723..0baa37b 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -134,6 +134,24 @@  static struct variant_data variant_ux500v2 = {
 };
 
 /*
+ * Validate mmc prerequisites
+ */
+static int mmci_validate_data(struct mmci_host *host,
+			      struct mmc_data *data)
+{
+	if (!data)
+		return 0;
+
+	if (!is_power_of_2(data->blksz)) {
+		dev_err(mmc_dev(host->mmc),
+			"unsupported block size (%d bytes)\n", data->blksz);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
  * This must be called with host->lock held
  */
 static void mmci_write_clkreg(struct mmci_host *host, u32 clk)
@@ -352,10 +370,33 @@  static inline void mmci_dma_release(struct mmci_host *host)
 	host->dma_rx_channel = host->dma_tx_channel = NULL;
 }
 
+static void mmci_dma_data_error(struct mmci_host *host)
+{
+	dev_err(mmc_dev(host->mmc), "error during DMA transfer!\n");
+	dmaengine_terminate_all(host->dma_current);
+	host->dma_current = NULL;
+	host->dma_desc_current = NULL;
+	host->data->host_cookie = 0;
+}
+
 static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
 {
-	struct dma_chan *chan = host->dma_current;
+	struct dma_chan *chan;
 	enum dma_data_direction dir;
+
+	if (data->flags & MMC_DATA_READ) {
+		dir = DMA_FROM_DEVICE;
+		chan = host->dma_rx_channel;
+	} else {
+		dir = DMA_TO_DEVICE;
+		chan = host->dma_tx_channel;
+	}
+
+	dma_unmap_sg(chan->device->dev, data->sg, data->sg_len, dir);
+}
+
+static void mmci_dma_finalize(struct mmci_host *host, struct mmc_data *data)
+{
 	u32 status;
 	int i;
 
@@ -374,19 +415,12 @@  static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
 	 * contiguous buffers.  On TX, we'll get a FIFO underrun error.
 	 */
 	if (status & MCI_RXDATAAVLBLMASK) {
-		dmaengine_terminate_all(chan);
-		if (!data->error)
-			data->error = -EIO;
-	}
-
-	if (data->flags & MMC_DATA_WRITE) {
-		dir = DMA_TO_DEVICE;
-	} else {
-		dir = DMA_FROM_DEVICE;
+		data->error = -EIO;
+		mmci_dma_data_error(host);
 	}
 
 	if (!data->host_cookie)
-		dma_unmap_sg(chan->device->dev, data->sg, data->sg_len, dir);
+		mmci_dma_unmap(host, data);
 
 	/*
 	 * Use of DMA with scatter-gather is impossible.
@@ -396,16 +430,15 @@  static void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
 		dev_err(mmc_dev(host->mmc), "buggy DMA detected. Taking evasive action.\n");
 		mmci_dma_release(host);
 	}
-}
 
-static void mmci_dma_data_error(struct mmci_host *host)
-{
-	dev_err(mmc_dev(host->mmc), "error during DMA transfer!\n");
-	dmaengine_terminate_all(host->dma_current);
+	host->dma_current = NULL;
+	host->dma_desc_current = NULL;
 }
 
-static int mmci_dma_prep_data(struct mmci_host *host, struct mmc_data *data,
-			      struct mmci_host_next *next)
+/* prepares DMA channel and DMA descriptor, returns non-zero on failure */
+static int __mmci_dma_prep_data(struct mmci_host *host, struct mmc_data *data,
+				struct dma_chan **dma_chan,
+				struct dma_async_tx_descriptor **dma_desc)
 {
 	struct variant_data *variant = host->variant;
 	struct dma_slave_config conf = {
@@ -423,16 +456,6 @@  static int mmci_dma_prep_data(struct mmci_host *host, struct mmc_data *data,
 	enum dma_data_direction buffer_dirn;
 	int nr_sg;
 
-	/* Check if next job is already prepared */
-	if (data->host_cookie && !next &&
-	    host->dma_current && host->dma_desc_current)
-		return 0;
-
-	if (!next) {
-		host->dma_current = NULL;
-		host->dma_desc_current = NULL;
-	}
-
 	if (data->flags & MMC_DATA_READ) {
 		conf.direction = DMA_DEV_TO_MEM;
 		buffer_dirn = DMA_FROM_DEVICE;
@@ -462,29 +485,41 @@  static int mmci_dma_prep_data(struct mmci_host *host, struct mmc_data *data,
 	if (!desc)
 		goto unmap_exit;
 
-	if (next) {
-		next->dma_chan = chan;
-		next->dma_desc = desc;
-	} else {
-		host->dma_current = chan;
-		host->dma_desc_current = desc;
-	}
+	*dma_chan = chan;
+	*dma_desc = desc;
 
 	return 0;
 
  unmap_exit:
-	if (!next)
-		dmaengine_terminate_all(chan);
 	dma_unmap_sg(device->dev, data->sg, data->sg_len, buffer_dirn);
 	return -ENOMEM;
 }
 
+static inline int mmci_dma_prep_data(struct mmci_host *host,
+				     struct mmc_data *data)
+{
+	/* Check if next job is already prepared. */
+	if (host->dma_current && host->dma_desc_current)
+		return 0;
+
+	/* No job were prepared thus do it now. */
+	return __mmci_dma_prep_data(host, data, &host->dma_current,
+				    &host->dma_desc_current);
+}
+
+static inline int mmci_dma_prep_next(struct mmci_host *host,
+				     struct mmc_data *data)
+{
+	struct mmci_host_next *nd = &host->next_data;
+	return __mmci_dma_prep_data(host, data, &nd->dma_chan, &nd->dma_desc);
+}
+
 static int mmci_dma_start_data(struct mmci_host *host, unsigned int datactrl)
 {
 	int ret;
 	struct mmc_data *data = host->data;
 
-	ret = mmci_dma_prep_data(host, host->data, NULL);
+	ret = mmci_dma_prep_data(host, host->data);
 	if (ret)
 		return ret;
 
@@ -514,19 +549,11 @@  static void mmci_get_next_data(struct mmci_host *host, struct mmc_data *data)
 {
 	struct mmci_host_next *next = &host->next_data;
 
-	if (data->host_cookie && data->host_cookie != next->cookie) {
-		pr_warning("[%s] invalid cookie: data->host_cookie %d"
-		       " host->next_data.cookie %d\n",
-		       __func__, data->host_cookie, host->next_data.cookie);
-		data->host_cookie = 0;
-	}
-
-	if (!data->host_cookie)
-		return;
+	WARN_ON(data->host_cookie && data->host_cookie != next->cookie);
+	WARN_ON(!data->host_cookie && (next->dma_desc || next->dma_chan));
 
 	host->dma_desc_current = next->dma_desc;
 	host->dma_current = next->dma_chan;
-
 	next->dma_desc = NULL;
 	next->dma_chan = NULL;
 }
@@ -541,19 +568,13 @@  static void mmci_pre_request(struct mmc_host *mmc, struct mmc_request *mrq,
 	if (!data)
 		return;
 
-	if (data->host_cookie) {
-		data->host_cookie = 0;
+	BUG_ON(data->host_cookie);
+
+	if (mmci_validate_data(host, data))
 		return;
-	}
 
-	/* if config for dma */
-	if (((data->flags & MMC_DATA_WRITE) && host->dma_tx_channel) ||
-	    ((data->flags & MMC_DATA_READ) && host->dma_rx_channel)) {
-		if (mmci_dma_prep_data(host, data, nd))
-			data->host_cookie = 0;
-		else
-			data->host_cookie = ++nd->cookie < 0 ? 1 : nd->cookie;
-	}
+	if (!mmci_dma_prep_next(host, data))
+		data->host_cookie = ++nd->cookie < 0 ? 1 : nd->cookie;
 }
 
 static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
@@ -561,29 +582,23 @@  static void mmci_post_request(struct mmc_host *mmc, struct mmc_request *mrq,
 {
 	struct mmci_host *host = mmc_priv(mmc);
 	struct mmc_data *data = mrq->data;
-	struct dma_chan *chan;
-	enum dma_data_direction dir;
 
-	if (!data)
+	if (!data || !data->host_cookie)
 		return;
 
-	if (data->flags & MMC_DATA_READ) {
-		dir = DMA_FROM_DEVICE;
-		chan = host->dma_rx_channel;
-	} else {
-		dir = DMA_TO_DEVICE;
-		chan = host->dma_tx_channel;
-	}
+	mmci_dma_unmap(host, data);
 
+	if (err) {
+		struct mmci_host_next *next = &host->next_data;
+		struct dma_chan *chan;
+		if (data->flags & MMC_DATA_READ)
+			chan = host->dma_rx_channel;
+		else
+			chan = host->dma_tx_channel;
+		dmaengine_terminate_all(chan);
 
-	/* if config for dma */
-	if (chan) {
-		if (err)
-			dmaengine_terminate_all(chan);
-		if (data->host_cookie)
-			dma_unmap_sg(mmc_dev(host->mmc), data->sg,
-				     data->sg_len, dir);
-		mrq->data->host_cookie = 0;
+		next->dma_desc = NULL;
+		next->dma_chan = NULL;
 	}
 }
 
@@ -604,6 +619,11 @@  static inline void mmci_dma_unmap(struct mmci_host *host, struct mmc_data *data)
 {
 }
 
+static inline void mmci_dma_finalize(struct mmci_host *host,
+				     struct mmc_data *data)
+{
+}
+
 static inline void mmci_dma_data_error(struct mmci_host *host)
 {
 }
@@ -751,8 +771,10 @@  mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
 		u32 remain, success;
 
 		/* Terminate the DMA transfer */
-		if (dma_inprogress(host))
+		if (dma_inprogress(host)) {
 			mmci_dma_data_error(host);
+			mmci_dma_unmap(host, data);
+		}
 
 		/*
 		 * Calculate how far we are into the transfer.  Note that
@@ -791,7 +813,7 @@  mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
 
 	if (status & MCI_DATAEND || data->error) {
 		if (dma_inprogress(host))
-			mmci_dma_unmap(host, data);
+			mmci_dma_finalize(host, data);
 		mmci_stop_data(host);
 
 		if (!data->error)
@@ -828,8 +850,10 @@  mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
 	if (!cmd->data || cmd->error) {
 		if (host->data) {
 			/* Terminate the DMA transfer */
-			if (dma_inprogress(host))
+			if (dma_inprogress(host)) {
 				mmci_dma_data_error(host);
+				mmci_dma_unmap(host, host->data);
+			}
 			mmci_stop_data(host);
 		}
 		mmci_request_end(host, cmd->mrq);
@@ -1055,10 +1079,8 @@  static void mmci_request(struct mmc_host *mmc, struct mmc_request *mrq)
 
 	WARN_ON(host->mrq != NULL);
 
-	if (mrq->data && !is_power_of_2(mrq->data->blksz)) {
-		dev_err(mmc_dev(mmc), "unsupported block size (%d bytes)\n",
-			mrq->data->blksz);
-		mrq->cmd->error = -EINVAL;
+	mrq->cmd->error = mmci_validate_data(host, mrq->data);
+	if (mrq->cmd->error) {
 		mmc_request_done(mmc, mrq);
 		return;
 	}