apm821xx: dw_dmac: backport fixes and cleanups from 4.7

This patch fixes the dw_dmac dma engine which is used
by the SATA controllers in the MyBook Live Series and WNDR4700.

The code was backported from the upstream kernel.
It can be dropped completely on 4.7+.

Signed-off-by: Christian Lamparter <chunkeey@gmail.com>

1 files changed, 345 insertions, 0 deletions

diff --git a/target/linux/apm821xx/patches-4.4/011-dmaengine-core-Introduce-new-universal-API-to-reques.patch b/target/linux/apm821xx/patches-4.4/011-dmaengine-core-Introduce-new-universal-API-to-reques.patch
new file mode 100644
index 0000000000..0296714639
--- /dev/null
+++ b/target/linux/apm821xx/patches-4.4/011-dmaengine-core-Introduce-new-universal-API-to-reques.patch
@@ -0,0 +1,345 @@
+From a8135d0d79e9d0ad3a4ff494fceeaae838becf38 Mon Sep 17 00:00:00 2001
+From: Peter Ujfalusi <peter.ujfalusi@ti.com>
+Date: Mon, 14 Dec 2015 22:47:40 +0200
+Subject: [PATCH 2/3] dmaengine: core: Introduce new, universal API to request
+ a channel
+
+The two API function can cover most, if not all current APIs used to
+request a channel. With minimal effort dmaengine drivers, platforms and
+dmaengine user drivers can be converted to use the two function.
+
+struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask);
+
+To request any channel matching with the requested capabilities, can be
+used to request channel for memcpy, memset, xor, etc where no hardware
+synchronization is needed.
+
+struct dma_chan *dma_request_chan(struct device *dev, const char *name);
+To request a slave channel. The dma_request_chan() will try to find the
+channel via DT, ACPI or in case if the kernel booted in non DT/ACPI mode
+it will use a filter lookup table and retrieves the needed information from
+the dma_slave_map provided by the DMA drivers.
+This legacy mode needs changes in platform code, in dmaengine drivers and
+finally the dmaengine user drivers can be converted:
+
+For each dmaengine driver an array of DMA device, slave and the parameter
+for the filter function needs to be added:
+
+static const struct dma_slave_map da830_edma_map[] = {
+	{ "davinci-mcasp.0", "rx", EDMA_FILTER_PARAM(0, 0) },
+	{ "davinci-mcasp.0", "tx", EDMA_FILTER_PARAM(0, 1) },
+	{ "davinci-mcasp.1", "rx", EDMA_FILTER_PARAM(0, 2) },
+	{ "davinci-mcasp.1", "tx", EDMA_FILTER_PARAM(0, 3) },
+	{ "davinci-mcasp.2", "rx", EDMA_FILTER_PARAM(0, 4) },
+	{ "davinci-mcasp.2", "tx", EDMA_FILTER_PARAM(0, 5) },
+	{ "spi_davinci.0", "rx", EDMA_FILTER_PARAM(0, 14) },
+	{ "spi_davinci.0", "tx", EDMA_FILTER_PARAM(0, 15) },
+	{ "da830-mmc.0", "rx", EDMA_FILTER_PARAM(0, 16) },
+	{ "da830-mmc.0", "tx", EDMA_FILTER_PARAM(0, 17) },
+	{ "spi_davinci.1", "rx", EDMA_FILTER_PARAM(0, 18) },
+	{ "spi_davinci.1", "tx", EDMA_FILTER_PARAM(0, 19) },
+};
+
+This information is going to be needed by the dmaengine driver, so
+modification to the platform_data is needed, and the driver map should be
+added to the pdata of the DMA driver:
+
+da8xx_edma0_pdata.slave_map = da830_edma_map;
+da8xx_edma0_pdata.slavecnt = ARRAY_SIZE(da830_edma_map);
+
+The DMA driver then needs to configure the needed device -> filter_fn
+mapping before it registers with dma_async_device_register() :
+
+ecc->dma_slave.filter_map.map = info->slave_map;
+ecc->dma_slave.filter_map.mapcnt = info->slavecnt;
+ecc->dma_slave.filter_map.fn = edma_filter_fn;
+
+When neither DT or ACPI lookup is available the dma_request_chan() will
+try to match the requester's device name with the filter_map's list of
+device names, when a match found it will use the information from the
+dma_slave_map to get the channel with the dma_get_channel() internal
+function.
+
+Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
+Reviewed-by: Arnd Bergmann <arnd@arndb.de>
+Signed-off-by: Vinod Koul <vinod.koul@intel.com>
+---
+ Documentation/dmaengine/client.txt | 23 +++-------
+ drivers/dma/dmaengine.c            | 89 +++++++++++++++++++++++++++++++++-----
+ include/linux/dmaengine.h          | 51 +++++++++++++++++++---
+ 3 files changed, 127 insertions(+), 36 deletions(-)
+
+diff --git a/Documentation/dmaengine/client.txt b/Documentation/dmaengine/client.txt
+index 11fb87f..4b04d89 100644
+--- a/Documentation/dmaengine/client.txt
++++ b/Documentation/dmaengine/client.txt
+@@ -22,25 +22,14 @@ The slave DMA usage consists of following steps:
+    Channel allocation is slightly different in the slave DMA context,
+    client drivers typically need a channel from a particular DMA
+    controller only and even in some cases a specific channel is desired.
+-   To request a channel dma_request_channel() API is used.
++   To request a channel dma_request_chan() API is used.
+ 
+    Interface:
+-	struct dma_chan *dma_request_channel(dma_cap_mask_t mask,
+-			dma_filter_fn filter_fn,
+-			void *filter_param);
+-   where dma_filter_fn is defined as:
+-	typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param);
+-
+-   The 'filter_fn' parameter is optional, but highly recommended for
+-   slave and cyclic channels as they typically need to obtain a specific
+-   DMA channel.
+-
+-   When the optional 'filter_fn' parameter is NULL, dma_request_channel()
+-   simply returns the first channel that satisfies the capability mask.
+-
+-   Otherwise, the 'filter_fn' routine will be called once for each free
+-   channel which has a capability in 'mask'.  'filter_fn' is expected to
+-   return 'true' when the desired DMA channel is found.
++	struct dma_chan *dma_request_chan(struct device *dev, const char *name);
++
++   Which will find and return the 'name' DMA channel associated with the 'dev'
++   device. The association is done via DT, ACPI or board file based
++   dma_slave_map matching table.
+ 
+    A channel allocated via this interface is exclusive to the caller,
+    until dma_release_channel() is called.
+diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
+index 81a36fc..a094dbb 100644
+--- a/drivers/dma/dmaengine.c
++++ b/drivers/dma/dmaengine.c
+@@ -43,6 +43,7 @@
+ 
+ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+ 
++#include <linux/platform_device.h>
+ #include <linux/dma-mapping.h>
+ #include <linux/init.h>
+ #include <linux/module.h>
+@@ -665,27 +666,73 @@ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+ }
+ EXPORT_SYMBOL_GPL(__dma_request_channel);
+ 
++static const struct dma_slave_map *dma_filter_match(struct dma_device *device,
++						    const char *name,
++						    struct device *dev)
++{
++	int i;
++
++	if (!device->filter.mapcnt)
++		return NULL;
++
++	for (i = 0; i < device->filter.mapcnt; i++) {
++		const struct dma_slave_map *map = &device->filter.map[i];
++
++		if (!strcmp(map->devname, dev_name(dev)) &&
++		    !strcmp(map->slave, name))
++			return map;
++	}
++
++	return NULL;
++}
++
+ /**
+- * dma_request_slave_channel_reason - try to allocate an exclusive slave channel
++ * dma_request_chan - try to allocate an exclusive slave channel
+  * @dev:	pointer to client device structure
+  * @name:	slave channel name
+  *
+  * Returns pointer to appropriate DMA channel on success or an error pointer.
+  */
+-struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
+-						  const char *name)
++struct dma_chan *dma_request_chan(struct device *dev, const char *name)
+ {
++	struct dma_device *d, *_d;
++	struct dma_chan *chan = NULL;
++
+ 	/* If device-tree is present get slave info from here */
+ 	if (dev->of_node)
+-		return of_dma_request_slave_channel(dev->of_node, name);
++		chan = of_dma_request_slave_channel(dev->of_node, name);
+ 
+ 	/* If device was enumerated by ACPI get slave info from here */
+-	if (ACPI_HANDLE(dev))
+-		return acpi_dma_request_slave_chan_by_name(dev, name);
++	if (has_acpi_companion(dev) && !chan)
++		chan = acpi_dma_request_slave_chan_by_name(dev, name);
++
++	if (chan) {
++		/* Valid channel found or requester need to be deferred */
++		if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
++			return chan;
++	}
++
++	/* Try to find the channel via the DMA filter map(s) */
++	mutex_lock(&dma_list_mutex);
++	list_for_each_entry_safe(d, _d, &dma_device_list, global_node) {
++		dma_cap_mask_t mask;
++		const struct dma_slave_map *map = dma_filter_match(d, name, dev);
++
++		if (!map)
++			continue;
++
++		dma_cap_zero(mask);
++		dma_cap_set(DMA_SLAVE, mask);
+ 
+-	return ERR_PTR(-ENODEV);
++		chan = find_candidate(d, &mask, d->filter.fn, map->param);
++		if (!IS_ERR(chan))
++			break;
++	}
++	mutex_unlock(&dma_list_mutex);
++
++	return chan ? chan : ERR_PTR(-EPROBE_DEFER);
+ }
+-EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
++EXPORT_SYMBOL_GPL(dma_request_chan);
+ 
+ /**
+  * dma_request_slave_channel - try to allocate an exclusive slave channel
+@@ -697,17 +744,35 @@ EXPORT_SYMBOL_GPL(dma_request_slave_channel_reason);
+ struct dma_chan *dma_request_slave_channel(struct device *dev,
+ 					   const char *name)
+ {
+-	struct dma_chan *ch = dma_request_slave_channel_reason(dev, name);
++	struct dma_chan *ch = dma_request_chan(dev, name);
+ 	if (IS_ERR(ch))
+ 		return NULL;
+ 
+-	dma_cap_set(DMA_PRIVATE, ch->device->cap_mask);
+-	ch->device->privatecnt++;
+-
+ 	return ch;
+ }
+ EXPORT_SYMBOL_GPL(dma_request_slave_channel);
+ 
++/**
++ * dma_request_chan_by_mask - allocate a channel satisfying certain capabilities
++ * @mask: capabilities that the channel must satisfy
++ *
++ * Returns pointer to appropriate DMA channel on success or an error pointer.
++ */
++struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask)
++{
++	struct dma_chan *chan;
++
++	if (!mask)
++		return ERR_PTR(-ENODEV);
++
++	chan = __dma_request_channel(mask, NULL, NULL);
++	if (!chan)
++		chan = ERR_PTR(-ENODEV);
++
++	return chan;
++}
++EXPORT_SYMBOL_GPL(dma_request_chan_by_mask);
++
+ void dma_release_channel(struct dma_chan *chan)
+ {
+ 	mutex_lock(&dma_list_mutex);
+diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
+index c47c68e..d50a6b51 100644
+--- a/include/linux/dmaengine.h
++++ b/include/linux/dmaengine.h
+@@ -607,11 +607,38 @@ enum dmaengine_alignment {
+ };
+ 
+ /**
++ * struct dma_slave_map - associates slave device and it's slave channel with
++ * parameter to be used by a filter function
++ * @devname: name of the device
++ * @slave: slave channel name
++ * @param: opaque parameter to pass to struct dma_filter.fn
++ */
++struct dma_slave_map {
++	const char *devname;
++	const char *slave;
++	void *param;
++};
++
++/**
++ * struct dma_filter - information for slave device/channel to filter_fn/param
++ * mapping
++ * @fn: filter function callback
++ * @mapcnt: number of slave device/channel in the map
++ * @map: array of channel to filter mapping data
++ */
++struct dma_filter {
++	dma_filter_fn fn;
++	int mapcnt;
++	const struct dma_slave_map *map;
++};
++
++/**
+  * struct dma_device - info on the entity supplying DMA services
+  * @chancnt: how many DMA channels are supported
+  * @privatecnt: how many DMA channels are requested by dma_request_channel
+  * @channels: the list of struct dma_chan
+  * @global_node: list_head for global dma_device_list
++ * @filter: information for device/slave to filter function/param mapping
+  * @cap_mask: one or more dma_capability flags
+  * @max_xor: maximum number of xor sources, 0 if no capability
+  * @max_pq: maximum number of PQ sources and PQ-continue capability
+@@ -666,6 +693,7 @@ struct dma_device {
+ 	unsigned int privatecnt;
+ 	struct list_head channels;
+ 	struct list_head global_node;
++	struct dma_filter filter;
+ 	dma_cap_mask_t  cap_mask;
+ 	unsigned short max_xor;
+ 	unsigned short max_pq;
+@@ -1140,9 +1168,11 @@ enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
+ void dma_issue_pending_all(void);
+ struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+ 					dma_filter_fn fn, void *fn_param);
+-struct dma_chan *dma_request_slave_channel_reason(struct device *dev,
+-						  const char *name);
+ struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
++
++struct dma_chan *dma_request_chan(struct device *dev, const char *name);
++struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask);
++
+ void dma_release_channel(struct dma_chan *chan);
+ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps);
+ #else
+@@ -1166,16 +1196,21 @@ static inline struct dma_chan *__dma_request_channel(const dma_cap_mask_t *mask,
+ {
+ 	return NULL;
+ }
+-static inline struct dma_chan *dma_request_slave_channel_reason(
+-					struct device *dev, const char *name)
+-{
+-	return ERR_PTR(-ENODEV);
+-}
+ static inline struct dma_chan *dma_request_slave_channel(struct device *dev,
+ 							 const char *name)
+ {
+ 	return NULL;
+ }
++static inline struct dma_chan *dma_request_chan(struct device *dev,
++						const char *name)
++{
++	return ERR_PTR(-ENODEV);
++}
++static inline struct dma_chan *dma_request_chan_by_mask(
++						const dma_cap_mask_t *mask)
++{
++	return ERR_PTR(-ENODEV);
++}
+ static inline void dma_release_channel(struct dma_chan *chan)
+ {
+ }
+@@ -1186,6 +1221,8 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
+ }
+ #endif
+ 
++#define dma_request_slave_channel_reason(dev, name) dma_request_chan(dev, name)
++
+ static inline int dmaengine_desc_set_reuse(struct dma_async_tx_descriptor *tx)
+ {
+ 	struct dma_slave_caps caps;
+-- 
+2.8.1
+