Patch "mmc: sh_mmcif: rework dma channel handling" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    mmc: sh_mmcif: rework dma channel handling

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mmc-sh_mmcif-rework-dma-channel-handling.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 27cbd7e815a8e223ff7c4fe56daca724101288ac Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 16 Nov 2015 17:08:41 +0100
Subject: mmc: sh_mmcif: rework dma channel handling

From: Arnd Bergmann <arnd@arndb.de>

commit 27cbd7e815a8e223ff7c4fe56daca724101288ac upstream.

When compiling the sh_mmcif driver for ARM64, we currently
get a harmless build warning:

../drivers/mmc/host/sh_mmcif.c: In function 'sh_mmcif_request_dma_one':
../drivers/mmc/host/sh_mmcif.c:417:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    (void *)pdata->slave_id_tx :
    ^
../drivers/mmc/host/sh_mmcif.c:418:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
    (void *)pdata->slave_id_rx;

This could be worked around by adding another cast to uintptr_t, but
I decided to simplify the code a little more to avoid that. This
splits out the platform data using code into a separate function
and builds that only for CONFIG_SUPERH. This part still has a typecast
but does not need a second one. The SH platform code could be further
modified to pass a pointer directly as we do on other architectures
when we have a filter function.

The normal case is simplified further and now just calls
dma_request_slave_channel() directly without going through the
compat handling.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/mmc/host/sh_mmcif.c |   84 +++++++++++++++++++-------------------------
 1 file changed, 38 insertions(+), 46 deletions(-)

--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -397,38 +397,26 @@ static void sh_mmcif_start_dma_tx(struct
 }
 
 static struct dma_chan *
-sh_mmcif_request_dma_one(struct sh_mmcif_host *host,
-			 struct sh_mmcif_plat_data *pdata,
-			 enum dma_transfer_direction direction)
+sh_mmcif_request_dma_pdata(struct sh_mmcif_host *host, uintptr_t slave_id)
 {
-	struct dma_slave_config cfg = { 0, };
-	struct dma_chan *chan;
-	void *slave_data = NULL;
-	struct resource *res;
-	struct device *dev = sh_mmcif_host_to_dev(host);
 	dma_cap_mask_t mask;
-	int ret;
 
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
+	if (slave_id <= 0)
+		return NULL;
 
-	if (pdata)
-		slave_data = direction == DMA_MEM_TO_DEV ?
-			(void *)pdata->slave_id_tx :
-			(void *)pdata->slave_id_rx;
-
-	chan = dma_request_slave_channel_compat(mask, shdma_chan_filter,
-				slave_data, dev,
-				direction == DMA_MEM_TO_DEV ? "tx" : "rx");
-
-	dev_dbg(dev, "%s: %s: got channel %p\n", __func__,
-		direction == DMA_MEM_TO_DEV ? "TX" : "RX", chan);
+	return dma_request_channel(mask, shdma_chan_filter, (void *)slave_id);
+}
 
-	if (!chan)
-		return NULL;
+static int sh_mmcif_dma_slave_config(struct sh_mmcif_host *host,
+				     struct dma_chan *chan,
+				     enum dma_transfer_direction direction)
+{
+	struct resource *res;
+	struct dma_slave_config cfg = { 0, };
 
 	res = platform_get_resource(host->pd, IORESOURCE_MEM, 0);
-
 	cfg.direction = direction;
 
 	if (direction == DMA_DEV_TO_MEM) {
@@ -439,38 +427,42 @@ sh_mmcif_request_dma_one(struct sh_mmcif
 		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 	}
 
-	ret = dmaengine_slave_config(chan, &cfg);
-	if (ret < 0) {
-		dma_release_channel(chan);
-		return NULL;
-	}
-
-	return chan;
+	return dmaengine_slave_config(chan, &cfg);
 }
 
-static void sh_mmcif_request_dma(struct sh_mmcif_host *host,
-				 struct sh_mmcif_plat_data *pdata)
+static void sh_mmcif_request_dma(struct sh_mmcif_host *host)
 {
 	struct device *dev = sh_mmcif_host_to_dev(host);
 	host->dma_active = false;
 
-	if (pdata) {
-		if (pdata->slave_id_tx <= 0 || pdata->slave_id_rx <= 0)
-			return;
-	} else if (!dev->of_node) {
-		return;
+	/* We can only either use DMA for both Tx and Rx or not use it at all */
+	if (IS_ENABLED(CONFIG_SUPERH) && dev->platform_data) {
+		struct sh_mmcif_plat_data *pdata = dev->platform_data;
+
+		host->chan_tx = sh_mmcif_request_dma_pdata(host,
+							pdata->slave_id_tx);
+		host->chan_rx = sh_mmcif_request_dma_pdata(host,
+							pdata->slave_id_rx);
+	} else {
+		host->chan_tx = dma_request_slave_channel(dev, "tx");
+		host->chan_tx = dma_request_slave_channel(dev, "rx");
 	}
+	dev_dbg(dev, "%s: got channel TX %p RX %p\n", __func__, host->chan_tx,
+		host->chan_rx);
 
-	/* We can only either use DMA for both Tx and Rx or not use it at all */
-	host->chan_tx = sh_mmcif_request_dma_one(host, pdata, DMA_MEM_TO_DEV);
-	if (!host->chan_tx)
-		return;
+	if (!host->chan_tx || !host->chan_rx ||
+	    sh_mmcif_dma_slave_config(host, host->chan_tx, DMA_MEM_TO_DEV) ||
+	    sh_mmcif_dma_slave_config(host, host->chan_rx, DMA_DEV_TO_MEM))
+		goto error;
 
-	host->chan_rx = sh_mmcif_request_dma_one(host, pdata, DMA_DEV_TO_MEM);
-	if (!host->chan_rx) {
+	return;
+
+error:
+	if (host->chan_tx)
 		dma_release_channel(host->chan_tx);
-		host->chan_tx = NULL;
-	}
+	if (host->chan_rx)
+		dma_release_channel(host->chan_rx);
+	host->chan_tx = host->chan_rx = NULL;
 }
 
 static void sh_mmcif_release_dma(struct sh_mmcif_host *host)
@@ -1102,7 +1094,7 @@ static void sh_mmcif_set_ios(struct mmc_
 	if (ios->power_mode == MMC_POWER_UP) {
 		if (!host->card_present) {
 			/* See if we also get DMA */
-			sh_mmcif_request_dma(host, dev->platform_data);
+			sh_mmcif_request_dma(host);
 			host->card_present = true;
 		}
 		sh_mmcif_set_power(host, ios);


Patches currently in stable-queue which might be from arnd@arndb.de are

queue-4.4/regulator-core-avoid-unused-variable-warning.patch
queue-4.4/asoc-samsung-pass-dma-channels-as-pointers.patch
queue-4.4/mmc-sh_mmcif-rework-dma-channel-handling.patch
queue-4.4/regulator-core-fix-nested-locking-of-supplies.patch
queue-4.4/mmc-sh_mmcif-correct-tx-dma-channel-allocation.patch