[PATCH RFC v12 0/7] MPC512x DMA slave s/g support, OF DMA lookup

[PATCH RFC v12 0/7] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

2013/7/14 Gerhard Sittig <gsi-ynQEQJNshbs@public.gmane.org>:
> this series
> - introduces slave s/g support (that's support for DMA transfers which
>    involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
>    several aspects of what the suggested LPB driver needs, to demonstrate
>    how integration might be done
> - carries Q&D SD card support to enable another DMA client during test,
>    while this patch needs to get dropped upon pickup

Changes in v2:
> - re-order mpc8308 related code paths for improved readability, no
>    change in behaviour, introduction of symbolic channel names here
>    already
> - squash 'execute() start condition' and 'terminate all' into the
>    introduction of 'slave s/g prep' and 'device control' support; refuse
>    s/g lists with more than one item since slave support is operational
>    yet proper s/g support is missing (can get addressed later)
> - always start transfers from software on MPC8308 as there are no
>    external request lines for peripheral flow control
> - drop dt-bindings header file and symbolic channel names in OF nodes

Changes in v3 and v4:
 Part 1/5:
 - use #define instead of enum since individual channels don't require
    special handling.
 Part 2/5:
 - add a flag "will_access_peripheral" to DMA transfer descriptor
    according recommendations of Gerhard Sittig.
    This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
    and is evaluated in mpc_dma_execute() to choose a type of start for
    the transfer.
 - prevent descriptors of transfers which involve peripherals from
    being chained together;
    each of such transfers needs hardware initiated start.
 - add locking while working with struct mpc_dma_chan
    according recommendations of Lars-Peter Clausen.
 - remove default nbytes value. Client kernel modules must set
    src_maxburst and dst_maxburst fields of struct dma_slave_config (dmaengine.h).

Changes in v5:
 Part 2/5:
 - add and improve comments;
 - improve the code moving transfer descriptors from 'queued' to 'active' list
    in mpc_dma_execute();
 - allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
 - take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
 - improve checks of the transfer parameters;
 - provide the default value for 'maxburst' in mpc_dma_device_control().

Changes in v6:
 Part 2/5:
 - remove doubtful comment;
 - fix coding style issues;
 - set default value for 'maxburst' to 1 which applies to most cases;
 Part 3/5:
 - use dma_get_slave_channel() instead of dma_request_channel()
    in new function of_dma_xlate_by_chan_id() according recommendations of
    Arnd Bergmann;
 Part 4/5:
 - set DMA_PRIVATE flag for MPC512x DMA controller since its driver relies on
    of_dma_xlate_by_chan_id() which doesn't use dma_request_channel()
    any more; (removed in v7)
 - resolve little patch conflict;
 Part 5/5:
 - resolve little patch conflict;

Changes in v7:
 Part 2:
 - improve comment;
 Part 4:
 - split in two separate patches. Part 4/6 contains device tree
    binding document and in part 5/6 MPC512x DMA controller is registered
    for device tree channel lookup;
 - remove setting DMA_PRIVATE flag for MPC512x DMA controller from part 5/6;

Changes in v8:
 Part 2:
 - improve comments;
 - fix style issues;
 Part 6:
 - remove since it has become obsolete;

Changes in v9:
 A new patch (part 3/6) is added to this series according the
   feedback of Andy Shevchenko.
 Part 2/6:
 - keep style of the comments;
 - use is_slave_direction() instead of manual checks;
 - remove redundant else branches of the conditions;
 - make mpc_dma_device_control() return -ENXIO for unknown command;
 Part 6/6:
 - change according the new part 3/6;
 - fix style issues;

Changes in v10:
 Part 2/6:
 - don't use direction field of dma_slave_config in mpc_dma_device_control()
    but store settings in mpc_dma_chan for both DMA_DEV_TO_MEM and
    DMA_MEM_TO_DEV cases; then retrieve the needed values in
    mpc_dma_prep_slave_sg();
 - fix style issue and put 2014 instead of 2013;
 Part 3/6:
 - fix mpc_dma_probe() error path and mpc_dma_remove(): manually free IRQs and
    dispose IRQ mappings before devm_* takes care of other resources;
 Part 6/6:
 - change according the new part 3/6;
 - fix style issue;

Changes in v11:
 Part 5/6:
 - remake device tree binding document according the recommendations of
    Gerhard Sittig, Mark Rutland and Arnd Bergmann;

Changes in v12:
 A new patch (part 2/7) is added to this series.
 Part 6/7:
 - change the description of 'compatible' property according part 2/7;
 - improve the document according Gerhard's feedback;

> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
>    whether the DMA controller's driver shall actively reject it, the
>    information that's available so far suggests that peripheral transfers
>    to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
    do increment the peripheral "port's" address is easy with
    this implementation; but which options of the common API
    should be used for specifying such transfers?


Alexander Popov (7):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308
  dma: mpc512x: add support for peripheral transfers
  dma: mpc512x: fix freeing resources in mpc_dma_probe() and
    mpc_dma_remove()
  dma: of: add common xlate function for matching by channel id
  dma: mpc512x: add device tree binding document
  dma: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt        |  40 +++
 arch/powerpc/boot/dts/mpc5121.dtsi                 |   1 +
 arch/powerpc/boot/dts/mpc8308_p1m.dts              |   2 +-
 arch/powerpc/boot/dts/mpc8308rdb.dts               |   2 +-
 drivers/dma/mpc512x_dma.c                          | 346 ++++++++++++++++++---
 drivers/dma/of-dma.c                               |  35 +++
 include/linux/of_dma.h                             |   4 +
 7 files changed, 390 insertions(+), 40 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

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[PATCH RFC v12 0/7] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

2013/7/14 Gerhard Sittig <gsi@denx.de>:
> this series
> - introduces slave s/g support (that's support for DMA transfers which
>    involve peripherals in contrast to mem-to-mem transfers)
> - adds device tree based lookup support for DMA channels
> - combines floating patches and related feedback which already covered
>    several aspects of what the suggested LPB driver needs, to demonstrate
>    how integration might be done
> - carries Q&D SD card support to enable another DMA client during test,
>    while this patch needs to get dropped upon pickup

Changes in v2:
> - re-order mpc8308 related code paths for improved readability, no
>    change in behaviour, introduction of symbolic channel names here
>    already
> - squash 'execute() start condition' and 'terminate all' into the
>    introduction of 'slave s/g prep' and 'device control' support; refuse
>    s/g lists with more than one item since slave support is operational
>    yet proper s/g support is missing (can get addressed later)
> - always start transfers from software on MPC8308 as there are no
>    external request lines for peripheral flow control
> - drop dt-bindings header file and symbolic channel names in OF nodes

Changes in v3 and v4:
 Part 1/5:
 - use #define instead of enum since individual channels don't require
    special handling.
 Part 2/5:
 - add a flag "will_access_peripheral" to DMA transfer descriptor
    according recommendations of Gerhard Sittig.
    This flag is set in mpc_dma_prep_memcpy() and mpc_dma_prep_slave_sg()
    and is evaluated in mpc_dma_execute() to choose a type of start for
    the transfer.
 - prevent descriptors of transfers which involve peripherals from
    being chained together;
    each of such transfers needs hardware initiated start.
 - add locking while working with struct mpc_dma_chan
    according recommendations of Lars-Peter Clausen.
 - remove default nbytes value. Client kernel modules must set
    src_maxburst and dst_maxburst fields of struct dma_slave_config (dmaengine.h).

Changes in v5:
 Part 2/5:
 - add and improve comments;
 - improve the code moving transfer descriptors from 'queued' to 'active' list
    in mpc_dma_execute();
 - allow mpc_dma_prep_slave_sg() to run with non-empty 'active' list;
 - take 'mdesc' back to 'free' list in case of error in mpc_dma_prep_slave_sg();
 - improve checks of the transfer parameters;
 - provide the default value for 'maxburst' in mpc_dma_device_control().

Changes in v6:
 Part 2/5:
 - remove doubtful comment;
 - fix coding style issues;
 - set default value for 'maxburst' to 1 which applies to most cases;
 Part 3/5:
 - use dma_get_slave_channel() instead of dma_request_channel()
    in new function of_dma_xlate_by_chan_id() according recommendations of
    Arnd Bergmann;
 Part 4/5:
 - set DMA_PRIVATE flag for MPC512x DMA controller since its driver relies on
    of_dma_xlate_by_chan_id() which doesn't use dma_request_channel()
    any more; (removed in v7)
 - resolve little patch conflict;
 Part 5/5:
 - resolve little patch conflict;

Changes in v7:
 Part 2:
 - improve comment;
 Part 4:
 - split in two separate patches. Part 4/6 contains device tree
    binding document and in part 5/6 MPC512x DMA controller is registered
    for device tree channel lookup;
 - remove setting DMA_PRIVATE flag for MPC512x DMA controller from part 5/6;

Changes in v8:
 Part 2:
 - improve comments;
 - fix style issues;
 Part 6:
 - remove since it has become obsolete;

Changes in v9:
 A new patch (part 3/6) is added to this series according the
   feedback of Andy Shevchenko.
 Part 2/6:
 - keep style of the comments;
 - use is_slave_direction() instead of manual checks;
 - remove redundant else branches of the conditions;
 - make mpc_dma_device_control() return -ENXIO for unknown command;
 Part 6/6:
 - change according the new part 3/6;
 - fix style issues;

Changes in v10:
 Part 2/6:
 - don't use direction field of dma_slave_config in mpc_dma_device_control()
    but store settings in mpc_dma_chan for both DMA_DEV_TO_MEM and
    DMA_MEM_TO_DEV cases; then retrieve the needed values in
    mpc_dma_prep_slave_sg();
 - fix style issue and put 2014 instead of 2013;
 Part 3/6:
 - fix mpc_dma_probe() error path and mpc_dma_remove(): manually free IRQs and
    dispose IRQ mappings before devm_* takes care of other resources;
 Part 6/6:
 - change according the new part 3/6;
 - fix style issue;

Changes in v11:
 Part 5/6:
 - remake device tree binding document according the recommendations of
    Gerhard Sittig, Mark Rutland and Arnd Bergmann;

Changes in v12:
 A new patch (part 2/7) is added to this series.
 Part 6/7:
 - change the description of 'compatible' property according part 2/7;
 - improve the document according Gerhard's feedback;

> known issues:
> - it's yet to get confirmed whether MPC8308 can use slave support or
>    whether the DMA controller's driver shall actively reject it, the
>    information that's available so far suggests that peripheral transfers
>    to IP bus attached I/O is useful and shall not get blocked right away
 - adding support for transfers which don't increment the RAM address or
    do increment the peripheral "port's" address is easy with
    this implementation; but which options of the common API
    should be used for specifying such transfers?


Alexander Popov (7):
  dma: mpc512x: reorder mpc8308 specific instructions
  dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308
  dma: mpc512x: add support for peripheral transfers
  dma: mpc512x: fix freeing resources in mpc_dma_probe() and
    mpc_dma_remove()
  dma: of: add common xlate function for matching by channel id
  dma: mpc512x: add device tree binding document
  dma: mpc512x: register for device tree channel lookup

 .../devicetree/bindings/dma/mpc512x-dma.txt        |  40 +++
 arch/powerpc/boot/dts/mpc5121.dtsi                 |   1 +
 arch/powerpc/boot/dts/mpc8308_p1m.dts              |   2 +-
 arch/powerpc/boot/dts/mpc8308rdb.dts               |   2 +-
 drivers/dma/mpc512x_dma.c                          | 346 ++++++++++++++++++---
 drivers/dma/of-dma.c                               |  35 +++
 include/linux/of_dma.h                             |   4 +
 7 files changed, 390 insertions(+), 40 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

-- 
1.8.4.2

[PATCH RFC v12 1/7] dma: mpc512x: reorder mpc8308 specific instructions

[Alexander Popov]

Concentrate the specific code for MPC8308 in the 'if' branch
and handle MPC512x in the 'else' branch.
This modification only reorders instructions but doesn't change behaviour.

Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
Acked-by: Anatolij Gustschin <agust@denx.de>
---
 drivers/dma/mpc512x_dma.c | 42 +++++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 448750d..2ce248b 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,9 +52,17 @@
 #define MPC_DMA_DESCRIPTORS	64
 
 /* Macro definitions */
-#define MPC_DMA_CHANNELS	64
 #define MPC_DMA_TCD_OFFSET	0x1000
 
+/*
+ * Maximum channel counts for individual hardware variants
+ * and the maximum channel count over all supported controllers,
+ * used for data structure size
+ */
+#define MPC8308_DMACHAN_MAX	16
+#define MPC512x_DMACHAN_MAX	64
+#define MPC_DMA_CHANNELS	64
+
 /* Arbitration mode of group and channel */
 #define MPC_DMA_DMACR_EDCG	(1 << 31)
 #define MPC_DMA_DMACR_ERGA	(1 << 3)
@@ -710,10 +718,10 @@ static int mpc_dma_probe(struct platform_device *op)
 
 	dma = &mdma->dma;
 	dma->dev = dev;
-	if (!mdma->is_mpc8308)
-		dma->chancnt = MPC_DMA_CHANNELS;
+	if (mdma->is_mpc8308)
+		dma->chancnt = MPC8308_DMACHAN_MAX;
 	else
-		dma->chancnt = 16; /* MPC8308 DMA has only 16 channels */
+		dma->chancnt = MPC512x_DMACHAN_MAX;
 	dma->device_alloc_chan_resources = mpc_dma_alloc_chan_resources;
 	dma->device_free_chan_resources = mpc_dma_free_chan_resources;
 	dma->device_issue_pending = mpc_dma_issue_pending;
@@ -747,7 +755,19 @@ static int mpc_dma_probe(struct platform_device *op)
 	 * - Round-robin group arbitration,
 	 * - Round-robin channel arbitration.
 	 */
-	if (!mdma->is_mpc8308) {
+	if (mdma->is_mpc8308) {
+		/* MPC8308 has 16 channels and lacks some registers */
+		out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
+
+		/* enable snooping */
+		out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
+		/* Disable error interrupts */
+		out_be32(&mdma->regs->dmaeeil, 0);
+
+		/* Clear interrupts status */
+		out_be32(&mdma->regs->dmaintl, 0xFFFF);
+		out_be32(&mdma->regs->dmaerrl, 0xFFFF);
+	} else {
 		out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_EDCG |
 					MPC_DMA_DMACR_ERGA | MPC_DMA_DMACR_ERCA);
 
@@ -768,18 +788,6 @@ static int mpc_dma_probe(struct platform_device *op)
 		/* Route interrupts to IPIC */
 		out_be32(&mdma->regs->dmaihsa, 0);
 		out_be32(&mdma->regs->dmailsa, 0);
-	} else {
-		/* MPC8308 has 16 channels and lacks some registers */
-		out_be32(&mdma->regs->dmacr, MPC_DMA_DMACR_ERCA);
-
-		/* enable snooping */
-		out_be32(&mdma->regs->dmagpor, MPC_DMA_DMAGPOR_SNOOP_ENABLE);
-		/* Disable error interrupts */
-		out_be32(&mdma->regs->dmaeeil, 0);
-
-		/* Clear interrupts status */
-		out_be32(&mdma->regs->dmaintl, 0xFFFF);
-		out_be32(&mdma->regs->dmaerrl, 0xFFFF);
 	}
 
 	/* Register DMA engine */
-- 
1.8.4.2

Re: [PATCH RFC v12 1/7] dma: mpc512x: reorder mpc8308 specific instructions

[Vinod Koul]

On Wed, Apr 23, 2014 at 05:53:23PM +0400, Alexander Popov wrote:
> Concentrate the specific code for MPC8308 in the 'if' branch
> and handle MPC512x in the 'else' branch.
> This modification only reorders instructions but doesn't change behaviour.
> 
> Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
> Acked-by: Anatolij Gustschin <agust@denx.de>

Applied, thanks

-- 
~Vinod

[PATCH RFC v12 3/7] dma: mpc512x: add support for peripheral transfers

[Alexander Popov]

Introduce support for slave s/g transfer preparation and the associated
device control callback in the MPC512x DMA controller driver, which adds
support for data transfers between memory and peripheral I/O to the
previously supported mem-to-mem transfers.

Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
---
 drivers/dma/mpc512x_dma.c | 239 +++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 234 insertions(+), 5 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 0b17f4d..ca2fe03 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -2,6 +2,7 @@
  * Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
  * Copyright (C) Semihalf 2009
  * Copyright (C) Ilya Yanok, Emcraft Systems 2010
+ * Copyright (C) Alexander Popov, Promcontroller 2014
  *
  * Written by Piotr Ziecik <kosmo@semihalf.com>. Hardware description
  * (defines, structures and comments) was taken from MPC5121 DMA driver
@@ -29,8 +30,17 @@
  */
 
 /*
- * This is initial version of MPC5121 DMA driver. Only memory to memory
- * transfers are supported (tested using dmatest module).
+ * MPC512x and MPC8308 DMA driver. It supports
+ * memory to memory data transfers (tested using dmatest module) and
+ * data transfers between memory and peripheral I/O memory
+ * by means of slave s/g with these limitations:
+ *  - chunked transfers (transfers with more than one part) are refused
+ *     as long as proper support for scatter/gather is missing;
+ *  - transfers on MPC8308 always start from software as this SoC appears
+ *     not to have external request lines for peripheral flow control;
+ *  - minimal memory <-> I/O memory transfer chunk is 4 bytes and consequently
+ *     source and destination addresses must be 4-byte aligned
+ *     and transfer size must be aligned on (4 * maxburst) boundary;
  */
 
 #include <linux/module.h>
@@ -189,6 +199,7 @@ struct mpc_dma_desc {
 	dma_addr_t			tcd_paddr;
 	int				error;
 	struct list_head		node;
+	int				will_access_peripheral;
 };
 
 struct mpc_dma_chan {
@@ -201,6 +212,12 @@ struct mpc_dma_chan {
 	struct mpc_dma_tcd		*tcd;
 	dma_addr_t			tcd_paddr;
 
+	/* Settings for access to peripheral FIFO */
+	dma_addr_t			src_per_paddr;
+	u32				src_tcd_nunits;
+	dma_addr_t			dst_per_paddr;
+	u32				dst_tcd_nunits;
+
 	/* Lock for this structure */
 	spinlock_t			lock;
 };
@@ -251,8 +268,23 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
 	struct mpc_dma_desc *mdesc;
 	int cid = mchan->chan.chan_id;
 
-	/* Move all queued descriptors to active list */
-	list_splice_tail_init(&mchan->queued, &mchan->active);
+	while (!list_empty(&mchan->queued)) {
+		mdesc = list_first_entry(&mchan->queued,
+						struct mpc_dma_desc, node);
+		/*
+		 * Grab either several mem-to-mem transfer descriptors
+		 * or one peripheral transfer descriptor,
+		 * don't mix mem-to-mem and peripheral transfer descriptors
+		 * within the same 'active' list.
+		 */
+		if (mdesc->will_access_peripheral) {
+			if (list_empty(&mchan->active))
+				list_move_tail(&mdesc->node, &mchan->active);
+			break;
+		} else {
+			list_move_tail(&mdesc->node, &mchan->active);
+		}
+	}
 
 	/* Chain descriptors into one transaction */
 	list_for_each_entry(mdesc, &mchan->active, node) {
@@ -278,7 +310,17 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
 
 	if (first != prev)
 		mdma->tcd[cid].e_sg = 1;
-	out_8(&mdma->regs->dmassrt, cid);
+
+	if (mdma->is_mpc8308) {
+		/* MPC8308, no request lines, software initiated start */
+		out_8(&mdma->regs->dmassrt, cid);
+	} else if (first->will_access_peripheral) {
+		/* Peripherals involved, start by external request signal */
+		out_8(&mdma->regs->dmaserq, cid);
+	} else {
+		/* Memory to memory transfer, software initiated start */
+		out_8(&mdma->regs->dmassrt, cid);
+	}
 }
 
 /* Handle interrupt on one half of DMA controller (32 channels) */
@@ -596,6 +638,7 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
 	}
 
 	mdesc->error = 0;
+	mdesc->will_access_peripheral = 0;
 	tcd = mdesc->tcd;
 
 	/* Prepare Transfer Control Descriptor for this transaction */
@@ -643,6 +686,189 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
 	return &mdesc->desc;
 }
 
+static struct dma_async_tx_descriptor *
+mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction direction,
+		unsigned long flags, void *context)
+{
+	struct mpc_dma *mdma = dma_chan_to_mpc_dma(chan);
+	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
+	struct mpc_dma_desc *mdesc = NULL;
+	dma_addr_t per_paddr;
+	u32 tcd_nunits;
+	struct mpc_dma_tcd *tcd;
+	unsigned long iflags;
+	struct scatterlist *sg;
+	size_t len;
+	int iter, i;
+
+	/* Currently there is no proper support for scatter/gather */
+	if (sg_len != 1)
+		return NULL;
+
+	if (!is_slave_direction(direction))
+		return NULL;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		spin_lock_irqsave(&mchan->lock, iflags);
+
+		mdesc = list_first_entry(&mchan->free,
+						struct mpc_dma_desc, node);
+		if (!mdesc) {
+			spin_unlock_irqrestore(&mchan->lock, iflags);
+			/* Try to free completed descriptors */
+			mpc_dma_process_completed(mdma);
+			return NULL;
+		}
+
+		list_del(&mdesc->node);
+
+		if (direction == DMA_DEV_TO_MEM) {
+			per_paddr = mchan->src_per_paddr;
+			tcd_nunits = mchan->src_tcd_nunits;
+		} else {
+			per_paddr = mchan->dst_per_paddr;
+			tcd_nunits = mchan->dst_tcd_nunits;
+		}
+
+		spin_unlock_irqrestore(&mchan->lock, iflags);
+
+		if (per_paddr == 0 || tcd_nunits == 0)
+			goto err_prep;
+
+		mdesc->error = 0;
+		mdesc->will_access_peripheral = 1;
+
+		/* Prepare Transfer Control Descriptor for this transaction */
+		tcd = mdesc->tcd;
+
+		memset(tcd, 0, sizeof(struct mpc_dma_tcd));
+
+		if (!IS_ALIGNED(sg_dma_address(sg), 4))
+			goto err_prep;
+
+		if (direction == DMA_DEV_TO_MEM) {
+			tcd->saddr = per_paddr;
+			tcd->daddr = sg_dma_address(sg);
+			tcd->soff = 0;
+			tcd->doff = 4;
+		} else {
+			tcd->saddr = sg_dma_address(sg);
+			tcd->daddr = per_paddr;
+			tcd->soff = 4;
+			tcd->doff = 0;
+		}
+
+		tcd->ssize = MPC_DMA_TSIZE_4;
+		tcd->dsize = MPC_DMA_TSIZE_4;
+
+		len = sg_dma_len(sg);
+		tcd->nbytes = tcd_nunits * 4;
+		if (!IS_ALIGNED(len, tcd->nbytes))
+			goto err_prep;
+
+		iter = len / tcd->nbytes;
+		if (iter >= 1 << 15) {
+			/* len is too big */
+			goto err_prep;
+		}
+		/* citer_linkch contains the high bits of iter */
+		tcd->biter = iter & 0x1ff;
+		tcd->biter_linkch = iter >> 9;
+		tcd->citer = tcd->biter;
+		tcd->citer_linkch = tcd->biter_linkch;
+
+		tcd->e_sg = 0;
+		tcd->d_req = 1;
+
+		/* Place descriptor in prepared list */
+		spin_lock_irqsave(&mchan->lock, iflags);
+		list_add_tail(&mdesc->node, &mchan->prepared);
+		spin_unlock_irqrestore(&mchan->lock, iflags);
+	}
+
+	return &mdesc->desc;
+
+err_prep:
+	/* Put the descriptor back */
+	spin_lock_irqsave(&mchan->lock, iflags);
+	list_add_tail(&mdesc->node, &mchan->free);
+	spin_unlock_irqrestore(&mchan->lock, iflags);
+
+	return NULL;
+}
+
+static int mpc_dma_device_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+							unsigned long arg)
+{
+	struct mpc_dma_chan *mchan;
+	struct mpc_dma *mdma;
+	struct dma_slave_config *cfg;
+	unsigned long flags;
+
+	mchan = dma_chan_to_mpc_dma_chan(chan);
+	switch (cmd) {
+	case DMA_TERMINATE_ALL:
+		/* Disable channel requests */
+		mdma = dma_chan_to_mpc_dma(chan);
+
+		spin_lock_irqsave(&mchan->lock, flags);
+
+		out_8(&mdma->regs->dmacerq, chan->chan_id);
+		list_splice_tail_init(&mchan->prepared, &mchan->free);
+		list_splice_tail_init(&mchan->queued, &mchan->free);
+		list_splice_tail_init(&mchan->active, &mchan->free);
+
+		spin_unlock_irqrestore(&mchan->lock, flags);
+
+		return 0;
+	case DMA_SLAVE_CONFIG:
+		/*
+		 * Constraints:
+		 *  - only transfers between a peripheral device and
+		 *     memory are supported;
+		 *  - minimal transfer chunk is 4 bytes and consequently
+		 *     source and destination addresses must be 4-byte aligned
+		 *     and transfer size must be aligned on (4 * maxburst)
+		 *     boundary;
+		 *  - during the transfer RAM address is being incremented by
+		 *     the size of minimal transfer chunk;
+		 *  - peripheral port's address is constant during the transfer.
+		 */
+
+		cfg = (void *)arg;
+
+		if (cfg->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
+		    cfg->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
+		    !IS_ALIGNED(cfg->src_addr, 4) ||
+		    !IS_ALIGNED(cfg->dst_addr, 4)) {
+			return -EINVAL;
+		}
+
+		spin_lock_irqsave(&mchan->lock, flags);
+
+		mchan->src_per_paddr = cfg->src_addr;
+		mchan->src_tcd_nunits = cfg->src_maxburst;
+		mchan->dst_per_paddr = cfg->dst_addr;
+		mchan->dst_tcd_nunits = cfg->dst_maxburst;
+
+		/* Apply defaults */
+		if (mchan->src_tcd_nunits == 0)
+			mchan->src_tcd_nunits = 1;
+		if (mchan->dst_tcd_nunits == 0)
+			mchan->dst_tcd_nunits = 1;
+
+		spin_unlock_irqrestore(&mchan->lock, flags);
+
+		return 0;
+	default:
+		/* Unknown command */
+		break;
+	}
+
+	return -ENXIO;
+}
+
 static int mpc_dma_probe(struct platform_device *op)
 {
 	struct device_node *dn = op->dev.of_node;
@@ -727,9 +953,12 @@ static int mpc_dma_probe(struct platform_device *op)
 	dma->device_issue_pending = mpc_dma_issue_pending;
 	dma->device_tx_status = mpc_dma_tx_status;
 	dma->device_prep_dma_memcpy = mpc_dma_prep_memcpy;
+	dma->device_prep_slave_sg = mpc_dma_prep_slave_sg;
+	dma->device_control = mpc_dma_device_control;
 
 	INIT_LIST_HEAD(&dma->channels);
 	dma_cap_set(DMA_MEMCPY, dma->cap_mask);
+	dma_cap_set(DMA_SLAVE, dma->cap_mask);
 
 	for (i = 0; i < dma->chancnt; i++) {
 		mchan = &mdma->channels[i];
-- 
1.8.4.2

Re: [PATCH RFC v12 3/7] dma: mpc512x: add support for peripheral transfers

[Vinod Koul]

On Wed, Apr 23, 2014 at 05:53:25PM +0400, Alexander Popov wrote:
> Introduce support for slave s/g transfer preparation and the associated
> device control callback in the MPC512x DMA controller driver, which adds
> support for data transfers between memory and peripheral I/O to the
> previously supported mem-to-mem transfers.
> 
> Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
> ---
>  drivers/dma/mpc512x_dma.c | 239 +++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 234 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
> index 0b17f4d..ca2fe03 100644
> --- a/drivers/dma/mpc512x_dma.c
> +++ b/drivers/dma/mpc512x_dma.c
> @@ -2,6 +2,7 @@
>   * Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
>   * Copyright (C) Semihalf 2009
>   * Copyright (C) Ilya Yanok, Emcraft Systems 2010
> + * Copyright (C) Alexander Popov, Promcontroller 2014
>   *
>   * Written by Piotr Ziecik <kosmo@semihalf.com>. Hardware description
>   * (defines, structures and comments) was taken from MPC5121 DMA driver
> @@ -29,8 +30,17 @@
>   */
>  
>  /*
> - * This is initial version of MPC5121 DMA driver. Only memory to memory
> - * transfers are supported (tested using dmatest module).
> + * MPC512x and MPC8308 DMA driver. It supports
> + * memory to memory data transfers (tested using dmatest module) and
> + * data transfers between memory and peripheral I/O memory
> + * by means of slave s/g with these limitations:
> + *  - chunked transfers (transfers with more than one part) are refused
> + *     as long as proper support for scatter/gather is missing;
> + *  - transfers on MPC8308 always start from software as this SoC appears
> + *     not to have external request lines for peripheral flow control;
> + *  - minimal memory <-> I/O memory transfer chunk is 4 bytes and consequently
> + *     source and destination addresses must be 4-byte aligned
> + *     and transfer size must be aligned on (4 * maxburst) boundary;
>   */
>  
>  #include <linux/module.h>
> @@ -189,6 +199,7 @@ struct mpc_dma_desc {
>  	dma_addr_t			tcd_paddr;
>  	int				error;
>  	struct list_head		node;
> +	int				will_access_peripheral;
>  };
>  
>  struct mpc_dma_chan {
> @@ -201,6 +212,12 @@ struct mpc_dma_chan {
>  	struct mpc_dma_tcd		*tcd;
>  	dma_addr_t			tcd_paddr;
>  
> +	/* Settings for access to peripheral FIFO */
> +	dma_addr_t			src_per_paddr;
> +	u32				src_tcd_nunits;
> +	dma_addr_t			dst_per_paddr;
> +	u32				dst_tcd_nunits;
> +
>  	/* Lock for this structure */
>  	spinlock_t			lock;
>  };
> @@ -251,8 +268,23 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
>  	struct mpc_dma_desc *mdesc;
>  	int cid = mchan->chan.chan_id;
>  
> -	/* Move all queued descriptors to active list */
> -	list_splice_tail_init(&mchan->queued, &mchan->active);
> +	while (!list_empty(&mchan->queued)) {
> +		mdesc = list_first_entry(&mchan->queued,
> +						struct mpc_dma_desc, node);
> +		/*
> +		 * Grab either several mem-to-mem transfer descriptors
> +		 * or one peripheral transfer descriptor,
> +		 * don't mix mem-to-mem and peripheral transfer descriptors
> +		 * within the same 'active' list.
> +		 */
> +		if (mdesc->will_access_peripheral) {
> +			if (list_empty(&mchan->active))
> +				list_move_tail(&mdesc->node, &mchan->active);
> +			break;
> +		} else {
> +			list_move_tail(&mdesc->node, &mchan->active);
> +		}
> +	}
>  
>  	/* Chain descriptors into one transaction */
>  	list_for_each_entry(mdesc, &mchan->active, node) {
> @@ -278,7 +310,17 @@ static void mpc_dma_execute(struct mpc_dma_chan *mchan)
>  
>  	if (first != prev)
>  		mdma->tcd[cid].e_sg = 1;
> -	out_8(&mdma->regs->dmassrt, cid);
> +
> +	if (mdma->is_mpc8308) {
> +		/* MPC8308, no request lines, software initiated start */
> +		out_8(&mdma->regs->dmassrt, cid);
> +	} else if (first->will_access_peripheral) {
> +		/* Peripherals involved, start by external request signal */
> +		out_8(&mdma->regs->dmaserq, cid);
> +	} else {
> +		/* Memory to memory transfer, software initiated start */
> +		out_8(&mdma->regs->dmassrt, cid);
> +	}
>  }
>  
>  /* Handle interrupt on one half of DMA controller (32 channels) */
> @@ -596,6 +638,7 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
>  	}
>  
>  	mdesc->error = 0;
> +	mdesc->will_access_peripheral = 0;
>  	tcd = mdesc->tcd;
>  
>  	/* Prepare Transfer Control Descriptor for this transaction */
> @@ -643,6 +686,189 @@ mpc_dma_prep_memcpy(struct dma_chan *chan, dma_addr_t dst, dma_addr_t src,
>  	return &mdesc->desc;
>  }
>  
> +static struct dma_async_tx_descriptor *
> +mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> +		unsigned int sg_len, enum dma_transfer_direction direction,
> +		unsigned long flags, void *context)
> +{
> +	struct mpc_dma *mdma = dma_chan_to_mpc_dma(chan);
> +	struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
> +	struct mpc_dma_desc *mdesc = NULL;
> +	dma_addr_t per_paddr;
> +	u32 tcd_nunits;
> +	struct mpc_dma_tcd *tcd;
> +	unsigned long iflags;
> +	struct scatterlist *sg;
> +	size_t len;
> +	int iter, i;
> +
> +	/* Currently there is no proper support for scatter/gather */
Why? Is this HW or SW limitation?

> +	if (sg_len != 1)
> +		return NULL;
> +
> +	if (!is_slave_direction(direction))
> +		return NULL;
> +
> +	for_each_sg(sgl, sg, sg_len, i) {
Then this doesn't make sense...

> +		spin_lock_irqsave(&mchan->lock, iflags);
> +
> +		mdesc = list_first_entry(&mchan->free,
> +						struct mpc_dma_desc, node);
> +		if (!mdesc) {
> +			spin_unlock_irqrestore(&mchan->lock, iflags);
> +			/* Try to free completed descriptors */
> +			mpc_dma_process_completed(mdma);
> +			return NULL;
> +		}
> +
> +		list_del(&mdesc->node);
> +
> +		if (direction == DMA_DEV_TO_MEM) {
> +			per_paddr = mchan->src_per_paddr;
> +			tcd_nunits = mchan->src_tcd_nunits;
> +		} else {
> +			per_paddr = mchan->dst_per_paddr;
> +			tcd_nunits = mchan->dst_tcd_nunits;
> +		}
> +
> +		spin_unlock_irqrestore(&mchan->lock, iflags);
> +
> +		if (per_paddr == 0 || tcd_nunits == 0)
> +			goto err_prep;
> +
> +		mdesc->error = 0;
> +		mdesc->will_access_peripheral = 1;
> +
> +		/* Prepare Transfer Control Descriptor for this transaction */
> +		tcd = mdesc->tcd;
> +
> +		memset(tcd, 0, sizeof(struct mpc_dma_tcd));
> +
> +		if (!IS_ALIGNED(sg_dma_address(sg), 4))
> +			goto err_prep;
> +
> +		if (direction == DMA_DEV_TO_MEM) {
> +			tcd->saddr = per_paddr;
> +			tcd->daddr = sg_dma_address(sg);
> +			tcd->soff = 0;
> +			tcd->doff = 4;
what are these?

> +		} else {
> +			tcd->saddr = sg_dma_address(sg);
> +			tcd->daddr = per_paddr;
> +			tcd->soff = 4;
> +			tcd->doff = 0;
> +		}
> +
> +		tcd->ssize = MPC_DMA_TSIZE_4;
> +		tcd->dsize = MPC_DMA_TSIZE_4;
> +
> +		len = sg_dma_len(sg);
> +		tcd->nbytes = tcd_nunits * 4;
> +		if (!IS_ALIGNED(len, tcd->nbytes))
> +			goto err_prep;
> +
> +		iter = len / tcd->nbytes;
> +		if (iter >= 1 << 15) {
> +			/* len is too big */
> +			goto err_prep;
> +		}
> +		/* citer_linkch contains the high bits of iter */
> +		tcd->biter = iter & 0x1ff;
> +		tcd->biter_linkch = iter >> 9;
> +		tcd->citer = tcd->biter;
> +		tcd->citer_linkch = tcd->biter_linkch;
> +
> +		tcd->e_sg = 0;
> +		tcd->d_req = 1;
> +
> +		/* Place descriptor in prepared list */
> +		spin_lock_irqsave(&mchan->lock, iflags);
> +		list_add_tail(&mdesc->node, &mchan->prepared);
> +		spin_unlock_irqrestore(&mchan->lock, iflags);
> +	}
> +
> +	return &mdesc->desc;
> +
> +err_prep:
> +	/* Put the descriptor back */
> +	spin_lock_irqsave(&mchan->lock, iflags);
> +	list_add_tail(&mdesc->node, &mchan->free);
> +	spin_unlock_irqrestore(&mchan->lock, iflags);
> +
> +	return NULL;
> +}
> +
> +static int mpc_dma_device_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> +							unsigned long arg)
> +{
> +	struct mpc_dma_chan *mchan;
> +	struct mpc_dma *mdma;
> +	struct dma_slave_config *cfg;
> +	unsigned long flags;
> +
> +	mchan = dma_chan_to_mpc_dma_chan(chan);
> +	switch (cmd) {
> +	case DMA_TERMINATE_ALL:
> +		/* Disable channel requests */
> +		mdma = dma_chan_to_mpc_dma(chan);
> +
> +		spin_lock_irqsave(&mchan->lock, flags);
> +
> +		out_8(&mdma->regs->dmacerq, chan->chan_id);
> +		list_splice_tail_init(&mchan->prepared, &mchan->free);
> +		list_splice_tail_init(&mchan->queued, &mchan->free);
> +		list_splice_tail_init(&mchan->active, &mchan->free);
> +
> +		spin_unlock_irqrestore(&mchan->lock, flags);
> +
> +		return 0;
empty line after this pls

> +	case DMA_SLAVE_CONFIG:
> +		/*
> +		 * Constraints:
> +		 *  - only transfers between a peripheral device and
> +		 *     memory are supported;
> +		 *  - minimal transfer chunk is 4 bytes and consequently
> +		 *     source and destination addresses must be 4-byte aligned
> +		 *     and transfer size must be aligned on (4 * maxburst)
> +		 *     boundary;
> +		 *  - during the transfer RAM address is being incremented by
> +		 *     the size of minimal transfer chunk;
> +		 *  - peripheral port's address is constant during the transfer.
> +		 */
> +
> +		cfg = (void *)arg;
> +
> +		if (cfg->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
> +		    cfg->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
and why this limtation, doesnt seem covered above?

> +		    !IS_ALIGNED(cfg->src_addr, 4) ||
> +		    !IS_ALIGNED(cfg->dst_addr, 4)) {
> +			return -EINVAL;
> +		}
> +
> +		spin_lock_irqsave(&mchan->lock, flags);
> +
> +		mchan->src_per_paddr = cfg->src_addr;
> +		mchan->src_tcd_nunits = cfg->src_maxburst;
> +		mchan->dst_per_paddr = cfg->dst_addr;
> +		mchan->dst_tcd_nunits = cfg->dst_maxburst;
> +
> +		/* Apply defaults */
> +		if (mchan->src_tcd_nunits == 0)
> +			mchan->src_tcd_nunits = 1;
> +		if (mchan->dst_tcd_nunits == 0)
> +			mchan->dst_tcd_nunits = 1;
> +
> +		spin_unlock_irqrestore(&mchan->lock, flags);
> +
> +		return 0;
empty line here too

> +	default:
> +		/* Unknown command */
> +		break;
> +	}
> +
> +	return -ENXIO;
> +}
> +
>  static int mpc_dma_probe(struct platform_device *op)
>  {
>  	struct device_node *dn = op->dev.of_node;
> @@ -727,9 +953,12 @@ static int mpc_dma_probe(struct platform_device *op)
>  	dma->device_issue_pending = mpc_dma_issue_pending;
>  	dma->device_tx_status = mpc_dma_tx_status;
>  	dma->device_prep_dma_memcpy = mpc_dma_prep_memcpy;
> +	dma->device_prep_slave_sg = mpc_dma_prep_slave_sg;
> +	dma->device_control = mpc_dma_device_control;
>  
>  	INIT_LIST_HEAD(&dma->channels);
>  	dma_cap_set(DMA_MEMCPY, dma->cap_mask);
> +	dma_cap_set(DMA_SLAVE, dma->cap_mask);
>  
>  	for (i = 0; i < dma->chancnt; i++) {
>  		mchan = &mdma->channels[i];
> -- 
> 1.8.4.2
> 

-- 
~Vinod

Re: [PATCH RFC v12 3/7] dma: mpc512x: add support for peripheral transfers

[Alexander Popov]

Hello, Vinod.
Thanks for your feedback.

2014-05-02 21:03 GMT+04:00 Vinod Koul <vinod.koul@intel.com>:
> On Wed, Apr 23, 2014 at 05:53:25PM +0400, Alexander Popov wrote:
>> +static struct dma_async_tx_descriptor *
>> +mpc_dma_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
>> +             unsigned int sg_len, enum dma_transfer_direction direction,
>> +             unsigned long flags, void *context)
>> +{
>> +     struct mpc_dma *mdma = dma_chan_to_mpc_dma(chan);
>> +     struct mpc_dma_chan *mchan = dma_chan_to_mpc_dma_chan(chan);
>> +     struct mpc_dma_desc *mdesc = NULL;
>> +     dma_addr_t per_paddr;
>> +     u32 tcd_nunits;
>> +     struct mpc_dma_tcd *tcd;
>> +     unsigned long iflags;
>> +     struct scatterlist *sg;
>> +     size_t len;
>> +     int iter, i;
>> +
>> +     /* Currently there is no proper support for scatter/gather */
> Why? Is this HW or SW limitation?
This is the software limitation.

As Gerhard noticed, unfortunately the Linux DMA API combines
peripheral access with scatter/gather function.

But the original MPC512x DMA driver already uses scatter/gather feature
of the hardware for chaining together individual mpc_dma_desc's
in mpc_dma_execute() while mpc_dma_desc itself cannot use
scatter/gather feature, because each mpc_dma_desc is associated
with exactly one mpc_dma_tcd.

>> +             if (direction == DMA_DEV_TO_MEM) {
>> +                     tcd->saddr = per_paddr;
>> +                     tcd->daddr = sg_dma_address(sg);
>> +                     tcd->soff = 0;
>> +                     tcd->doff = 4;
> what are these?
SOFF is source address signed offset. It is applied to the current
source address to form the next-state value as each source read is completed.
DOFF is destination address signed offset.

>> +     case DMA_TERMINATE_ALL:
>> +             /* Disable channel requests */
>> +             mdma = dma_chan_to_mpc_dma(chan);
>> +
>> +             spin_lock_irqsave(&mchan->lock, flags);
>> +
>> +             out_8(&mdma->regs->dmacerq, chan->chan_id);
>> +             list_splice_tail_init(&mchan->prepared, &mchan->free);
>> +             list_splice_tail_init(&mchan->queued, &mchan->free);
>> +             list_splice_tail_init(&mchan->active, &mchan->free);
>> +
>> +             spin_unlock_irqrestore(&mchan->lock, flags);
>> +
>> +             return 0;
> empty line after this pls
ok

>> +     case DMA_SLAVE_CONFIG:
>> +             /*
>> +              * Constraints:
>> +              *  - only transfers between a peripheral device and
>> +              *     memory are supported;
>> +              *  - minimal transfer chunk is 4 bytes and consequently
>> +              *     source and destination addresses must be 4-byte aligned
>> +              *     and transfer size must be aligned on (4 * maxburst)
>> +              *     boundary;
>> +              *  - during the transfer RAM address is being incremented by
>> +              *     the size of minimal transfer chunk;
>> +              *  - peripheral port's address is constant during the transfer.
>> +              */
>> +
>> +             cfg = (void *)arg;
>> +
>> +             if (cfg->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
>> +                 cfg->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
> and why this limtation, doesnt seem covered above?
I created this limitation because FIFO registers of LPC and SDHC
support _only_ 4-byte access.

I tried to cover this limitation in the statement "minimal transfer chunk
is 4 bytes". Should I make it more explicit?

>> +                 !IS_ALIGNED(cfg->src_addr, 4) ||
>> +                 !IS_ALIGNED(cfg->dst_addr, 4)) {
>> +                     return -EINVAL;
>> +             }
>> +
>> +             spin_lock_irqsave(&mchan->lock, flags);
>> +
>> +             mchan->src_per_paddr = cfg->src_addr;
>> +             mchan->src_tcd_nunits = cfg->src_maxburst;
>> +             mchan->dst_per_paddr = cfg->dst_addr;
>> +             mchan->dst_tcd_nunits = cfg->dst_maxburst;
>> +
>> +             /* Apply defaults */
>> +             if (mchan->src_tcd_nunits == 0)
>> +                     mchan->src_tcd_nunits = 1;
>> +             if (mchan->dst_tcd_nunits == 0)
>> +                     mchan->dst_tcd_nunits = 1;
>> +
>> +             spin_unlock_irqrestore(&mchan->lock, flags);
>> +
>> +             return 0;
> empty line here too
ok

Best regards,
Alexander

Re: [PATCH RFC v12 3/7] dma: mpc512x: add support for peripheral transfers

[Vinod Koul]

On Thu, May 08, 2014 at 01:49:20PM +0400, Alexander Popov wrote:
> >> +     case DMA_SLAVE_CONFIG:
> >> +             /*
> >> +              * Constraints:
> >> +              *  - only transfers between a peripheral device and
> >> +              *     memory are supported;
> >> +              *  - minimal transfer chunk is 4 bytes and consequently
> >> +              *     source and destination addresses must be 4-byte aligned
> >> +              *     and transfer size must be aligned on (4 * maxburst)
> >> +              *     boundary;
> >> +              *  - during the transfer RAM address is being incremented by
> >> +              *     the size of minimal transfer chunk;
> >> +              *  - peripheral port's address is constant during the transfer.
> >> +              */
> >> +
> >> +             cfg = (void *)arg;
> >> +
> >> +             if (cfg->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
> >> +                 cfg->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES ||
> > and why this limtation, doesnt seem covered above?
> I created this limitation because FIFO registers of LPC and SDHC
> support _only_ 4-byte access.
> 
> I tried to cover this limitation in the statement "minimal transfer chunk
> is 4 bytes". Should I make it more explicit?
expose these as capablities and try to use these in your client driver. Already
we have audio drivers using those...

-- 
~Vinod

[PATCH RFC v12 4/7] dma: mpc512x: fix freeing resources in mpc_dma_probe() and mpc_dma_remove()

[Alexander Popov]

Fix mpc_dma_probe() error path and mpc_dma_remove(): manually free IRQs and
dispose IRQ mappings before devm_* takes care of other resources.
Moreover replace devm_request_irq() with request_irq() since there is no need
to use it because the original code always frees IRQ manually with
devm_free_irq(). Replace devm_free_irq() with free_irq() accordingly.

Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
---
 drivers/dma/mpc512x_dma.c | 55 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 38 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index ca2fe03..d2c5f79 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -883,13 +883,15 @@ static int mpc_dma_probe(struct platform_device *op)
 	mdma = devm_kzalloc(dev, sizeof(struct mpc_dma), GFP_KERNEL);
 	if (!mdma) {
 		dev_err(dev, "Memory exhausted!\n");
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto err;
 	}
 
 	mdma->irq = irq_of_parse_and_map(dn, 0);
 	if (mdma->irq == NO_IRQ) {
 		dev_err(dev, "Error mapping IRQ!\n");
-		return -EINVAL;
+		retval = -EINVAL;
+		goto err;
 	}
 
 	if (of_device_is_compatible(dn, "fsl,mpc8308-dma")) {
@@ -897,14 +899,15 @@ static int mpc_dma_probe(struct platform_device *op)
 		mdma->irq2 = irq_of_parse_and_map(dn, 1);
 		if (mdma->irq2 == NO_IRQ) {
 			dev_err(dev, "Error mapping IRQ!\n");
-			return -EINVAL;
+			retval = -EINVAL;
+			goto err_dispose1;
 		}
 	}
 
 	retval = of_address_to_resource(dn, 0, &res);
 	if (retval) {
 		dev_err(dev, "Error parsing memory region!\n");
-		return retval;
+		goto err_dispose2;
 	}
 
 	regs_start = res.start;
@@ -912,31 +915,34 @@ static int mpc_dma_probe(struct platform_device *op)
 
 	if (!devm_request_mem_region(dev, regs_start, regs_size, DRV_NAME)) {
 		dev_err(dev, "Error requesting memory region!\n");
-		return -EBUSY;
+		retval = -EBUSY;
+		goto err_dispose2;
 	}
 
 	mdma->regs = devm_ioremap(dev, regs_start, regs_size);
 	if (!mdma->regs) {
 		dev_err(dev, "Error mapping memory region!\n");
-		return -ENOMEM;
+		retval = -ENOMEM;
+		goto err_dispose2;
 	}
 
 	mdma->tcd = (struct mpc_dma_tcd *)((u8 *)(mdma->regs)
 							+ MPC_DMA_TCD_OFFSET);
 
-	retval = devm_request_irq(dev, mdma->irq, &mpc_dma_irq, 0, DRV_NAME,
-									mdma);
+	retval = request_irq(mdma->irq, &mpc_dma_irq, 0, DRV_NAME, mdma);
 	if (retval) {
 		dev_err(dev, "Error requesting IRQ!\n");
-		return -EINVAL;
+		retval = -EINVAL;
+		goto err_dispose2;
 	}
 
 	if (mdma->is_mpc8308) {
-		retval = devm_request_irq(dev, mdma->irq2, &mpc_dma_irq, 0,
-				DRV_NAME, mdma);
+		retval = request_irq(mdma->irq2, &mpc_dma_irq, 0,
+							DRV_NAME, mdma);
 		if (retval) {
 			dev_err(dev, "Error requesting IRQ2!\n");
-			return -EINVAL;
+			retval = -EINVAL;
+			goto err_free1;
 		}
 	}
 
@@ -1022,12 +1028,23 @@ static int mpc_dma_probe(struct platform_device *op)
 	/* Register DMA engine */
 	dev_set_drvdata(dev, mdma);
 	retval = dma_async_device_register(dma);
-	if (retval) {
-		devm_free_irq(dev, mdma->irq, mdma);
-		irq_dispose_mapping(mdma->irq);
-	}
+	if (retval)
+		goto err_free2;
 
 	return retval;
+
+err_free2:
+	if (mdma->is_mpc8308)
+		free_irq(mdma->irq2, mdma);
+err_free1:
+	free_irq(mdma->irq, mdma);
+err_dispose2:
+	if (mdma->is_mpc8308)
+		irq_dispose_mapping(mdma->irq2);
+err_dispose1:
+	irq_dispose_mapping(mdma->irq);
+err:
+	return retval;
 }
 
 static int mpc_dma_remove(struct platform_device *op)
@@ -1036,7 +1053,11 @@ static int mpc_dma_remove(struct platform_device *op)
 	struct mpc_dma *mdma = dev_get_drvdata(dev);
 
 	dma_async_device_unregister(&mdma->dma);
-	devm_free_irq(dev, mdma->irq, mdma);
+	if (mdma->is_mpc8308) {
+		free_irq(mdma->irq2, mdma);
+		irq_dispose_mapping(mdma->irq2);
+	}
+	free_irq(mdma->irq, mdma);
 	irq_dispose_mapping(mdma->irq);
 
 	return 0;
-- 
1.8.4.2

Re: [PATCH RFC v12 4/7] dma: mpc512x: fix freeing resources in mpc_dma_probe() and mpc_dma_remove()

[Vinod Koul]

On Wed, Apr 23, 2014 at 05:53:26PM +0400, Alexander Popov wrote:
> Fix mpc_dma_probe() error path and mpc_dma_remove(): manually free IRQs and
> dispose IRQ mappings before devm_* takes care of other resources.
> Moreover replace devm_request_irq() with request_irq() since there is no need
> to use it because the original code always frees IRQ manually with
> devm_free_irq(). Replace devm_free_irq() with free_irq() accordingly.
Applied, thanks

-- 
~Vinod

[PATCH RFC v12 2/7] dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308

[Alexander Popov]

MPC512x and MPC8308 have similar DMA controllers, but are independent SoCs.
DMA controller driver should have separate 'compatible' values for these SoCs.

Signed-off-by: Alexander Popov <a13xp0p0v88-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 arch/powerpc/boot/dts/mpc8308_p1m.dts | 2 +-
 arch/powerpc/boot/dts/mpc8308rdb.dts  | 2 +-
 drivers/dma/mpc512x_dma.c             | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc8308_p1m.dts b/arch/powerpc/boot/dts/mpc8308_p1m.dts
index 651e4f5..57f86cd 100644
--- a/arch/powerpc/boot/dts/mpc8308_p1m.dts
+++ b/arch/powerpc/boot/dts/mpc8308_p1m.dts
@@ -296,7 +296,7 @@
 		};
 
 		dma@2c000 {
-			compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+			compatible = "fsl,mpc8308-dma";
 			reg = <0x2c000 0x1800>;
 			interrupts = <3 0x8
 					94 0x8>;
diff --git a/arch/powerpc/boot/dts/mpc8308rdb.dts b/arch/powerpc/boot/dts/mpc8308rdb.dts
index 9ce45f2..d0211f0 100644
--- a/arch/powerpc/boot/dts/mpc8308rdb.dts
+++ b/arch/powerpc/boot/dts/mpc8308rdb.dts
@@ -265,7 +265,7 @@
 		};
 
 		dma@2c000 {
-			compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+			compatible = "fsl,mpc8308-dma";
 			reg = <0x2c000 0x1800>;
 			interrupts = <3 0x8
 					94 0x8>;
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ce248b..0b17f4d 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -815,6 +815,7 @@ static int mpc_dma_remove(struct platform_device *op)
 
 static struct of_device_id mpc_dma_match[] = {
 	{ .compatible = "fsl,mpc5121-dma", },
+	{ .compatible = "fsl,mpc8308-dma", },
 	{},
 };
 
-- 
1.8.4.2

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[PATCH RFC v12 2/7] dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308

[Alexander Popov]

MPC512x and MPC8308 have similar DMA controllers, but are independent SoCs.
DMA controller driver should have separate 'compatible' values for these SoCs.

Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
---
 arch/powerpc/boot/dts/mpc8308_p1m.dts | 2 +-
 arch/powerpc/boot/dts/mpc8308rdb.dts  | 2 +-
 drivers/dma/mpc512x_dma.c             | 1 +
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc8308_p1m.dts b/arch/powerpc/boot/dts/mpc8308_p1m.dts
index 651e4f5..57f86cd 100644
--- a/arch/powerpc/boot/dts/mpc8308_p1m.dts
+++ b/arch/powerpc/boot/dts/mpc8308_p1m.dts
@@ -296,7 +296,7 @@
 		};
 
 		dma@2c000 {
-			compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+			compatible = "fsl,mpc8308-dma";
 			reg = <0x2c000 0x1800>;
 			interrupts = <3 0x8
 					94 0x8>;
diff --git a/arch/powerpc/boot/dts/mpc8308rdb.dts b/arch/powerpc/boot/dts/mpc8308rdb.dts
index 9ce45f2..d0211f0 100644
--- a/arch/powerpc/boot/dts/mpc8308rdb.dts
+++ b/arch/powerpc/boot/dts/mpc8308rdb.dts
@@ -265,7 +265,7 @@
 		};
 
 		dma@2c000 {
-			compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+			compatible = "fsl,mpc8308-dma";
 			reg = <0x2c000 0x1800>;
 			interrupts = <3 0x8
 					94 0x8>;
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index 2ce248b..0b17f4d 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -815,6 +815,7 @@ static int mpc_dma_remove(struct platform_device *op)
 
 static struct of_device_id mpc_dma_match[] = {
 	{ .compatible = "fsl,mpc5121-dma", },
+	{ .compatible = "fsl,mpc8308-dma", },
 	{},
 };
 
-- 
1.8.4.2

Re: [PATCH RFC v12 2/7] dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308

[Vinod Koul]

On Wed, Apr 23, 2014 at 05:53:24PM +0400, Alexander Popov wrote:
> MPC512x and MPC8308 have similar DMA controllers, but are independent SoCs.
> DMA controller driver should have separate 'compatible' values for these SoCs.
> 
> Signed-off-by: Alexander Popov <a13xp0p0v88-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Applied, thanks

-- 
~Vinod
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Re: [PATCH RFC v12 2/7] dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308

[Vinod Koul]

On Wed, Apr 23, 2014 at 05:53:24PM +0400, Alexander Popov wrote:
> MPC512x and MPC8308 have similar DMA controllers, but are independent SoCs.
> DMA controller driver should have separate 'compatible' values for these SoCs.
> 
> Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
Applied, thanks

-- 
~Vinod

[PATCH RFC v12 5/7] dma: of: add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov <a13xp0p0v88-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 drivers/dma/of-dma.c   | 35 +++++++++++++++++++++++++++++++++++
 include/linux/of_dma.h |  4 ++++
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
 			&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:	pointer to DMA specifier as found in the device tree
+ * @of_dma:	pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+					 struct of_dma *ofdma)
+{
+	struct dma_device *dev = ofdma->of_dma_data;
+	struct dma_chan *chan, *candidate = NULL;
+
+	if (!dev || dma_spec->args_count != 1)
+		return NULL;
+
+	list_for_each_entry(chan, &dev->channels, device_node)
+		if (chan->chan_id == dma_spec->args[0]) {
+			candidate = chan;
+			break;
+		}
+
+	if (!candidate)
+		return NULL;
+
+	return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 						     const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
 		struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+		struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
 		struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
 	return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

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[PATCH RFC v12 5/7] dma: of: add common xlate function for matching by channel id

[Alexander Popov]

This patch adds a new common OF dma xlate callback function which will match a
channel by it's id. The binding expects one integer argument which it will use to
lookup the channel by the id.

Unlike of_dma_simple_xlate this function is able to handle a system with
multiple DMA controllers. When registering the of dma provider with
of_dma_controller_register a pointer to the dma_device struct which is
associated with the dt node needs to passed as the data parameter.
New function will use this pointer to match only channels which belong to the
specified DMA controller.

Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
---
 drivers/dma/of-dma.c   | 35 +++++++++++++++++++++++++++++++++++
 include/linux/of_dma.h |  4 ++++
 2 files changed, 39 insertions(+)

diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
index e8fe9dc..d5fbeaa 100644
--- a/drivers/dma/of-dma.c
+++ b/drivers/dma/of-dma.c
@@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
 			&dma_spec->args[0]);
 }
 EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
+
+/**
+ * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
+ * @dma_spec:	pointer to DMA specifier as found in the device tree
+ * @of_dma:	pointer to DMA controller data
+ *
+ * This function can be used as the of xlate callback for DMA driver which wants
+ * to match the channel based on the channel id. When using this xlate function
+ * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
+ * The data parameter of of_dma_controller_register must be a pointer to the
+ * dma_device struct the function should match upon.
+ *
+ * Returns pointer to appropriate dma channel on success or NULL on error.
+ */
+struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+					 struct of_dma *ofdma)
+{
+	struct dma_device *dev = ofdma->of_dma_data;
+	struct dma_chan *chan, *candidate = NULL;
+
+	if (!dev || dma_spec->args_count != 1)
+		return NULL;
+
+	list_for_each_entry(chan, &dev->channels, device_node)
+		if (chan->chan_id == dma_spec->args[0]) {
+			candidate = chan;
+			break;
+		}
+
+	if (!candidate)
+		return NULL;
+
+	return dma_get_slave_channel(candidate);
+}
+EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
index ae36298..56bc026 100644
--- a/include/linux/of_dma.h
+++ b/include/linux/of_dma.h
@@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
 						     const char *name);
 extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
 		struct of_dma *ofdma);
+extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
+		struct of_dma *ofdma);
 #else
 static inline int of_dma_controller_register(struct device_node *np,
 		struct dma_chan *(*of_dma_xlate)
@@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
 	return NULL;
 }
 
+#define of_dma_xlate_by_chan_id NULL
+
 #endif
 
 #endif /* __LINUX_OF_DMA_H */
-- 
1.8.4.2

Re: [PATCH RFC v12 5/7] dma: of: add common xlate function for matching by channel id

[Vinod Koul]

On Wed, Apr 23, 2014 at 05:53:27PM +0400, Alexander Popov wrote:
> This patch adds a new common OF dma xlate callback function which will match a
> channel by it's id. The binding expects one integer argument which it will use to
> lookup the channel by the id.
> 
> Unlike of_dma_simple_xlate this function is able to handle a system with
> multiple DMA controllers. When registering the of dma provider with
> of_dma_controller_register a pointer to the dma_device struct which is
> associated with the dt node needs to passed as the data parameter.
> New function will use this pointer to match only channels which belong to the
> specified DMA controller.

This patch needs review by DT folks too

> 
> Signed-off-by: Alexander Popov <a13xp0p0v88-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/dma/of-dma.c   | 35 +++++++++++++++++++++++++++++++++++
>  include/linux/of_dma.h |  4 ++++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
> index e8fe9dc..d5fbeaa 100644
> --- a/drivers/dma/of-dma.c
> +++ b/drivers/dma/of-dma.c
> @@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>  			&dma_spec->args[0]);
>  }
>  EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
> +
> +/**
> + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
> + * @dma_spec:	pointer to DMA specifier as found in the device tree
> + * @of_dma:	pointer to DMA controller data
> + *
> + * This function can be used as the of xlate callback for DMA driver which wants
> + * to match the channel based on the channel id. When using this xlate function
> + * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
> + * The data parameter of of_dma_controller_register must be a pointer to the
> + * dma_device struct the function should match upon.
> + *
> + * Returns pointer to appropriate dma channel on success or NULL on error.
> + */
> +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> +					 struct of_dma *ofdma)
> +{
> +	struct dma_device *dev = ofdma->of_dma_data;
> +	struct dma_chan *chan, *candidate = NULL;
> +
> +	if (!dev || dma_spec->args_count != 1)
> +		return NULL;
> +
> +	list_for_each_entry(chan, &dev->channels, device_node)
> +		if (chan->chan_id == dma_spec->args[0]) {
> +			candidate = chan;
> +			break;
> +		}
> +
> +	if (!candidate)
> +		return NULL;
> +
> +	return dma_get_slave_channel(candidate);
> +}
> +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
> diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
> index ae36298..56bc026 100644
> --- a/include/linux/of_dma.h
> +++ b/include/linux/of_dma.h
> @@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
>  						     const char *name);
>  extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>  		struct of_dma *ofdma);
> +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> +		struct of_dma *ofdma);
>  #else
>  static inline int of_dma_controller_register(struct device_node *np,
>  		struct dma_chan *(*of_dma_xlate)
> @@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
>  	return NULL;
>  }
>  
> +#define of_dma_xlate_by_chan_id NULL
> +
>  #endif
>  
>  #endif /* __LINUX_OF_DMA_H */
> -- 
> 1.8.4.2
> 

-- 
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Re: [PATCH RFC v12 5/7] dma: of: add common xlate function for matching by channel id

[Vinod Koul]

On Wed, Apr 23, 2014 at 05:53:27PM +0400, Alexander Popov wrote:
> This patch adds a new common OF dma xlate callback function which will match a
> channel by it's id. The binding expects one integer argument which it will use to
> lookup the channel by the id.
> 
> Unlike of_dma_simple_xlate this function is able to handle a system with
> multiple DMA controllers. When registering the of dma provider with
> of_dma_controller_register a pointer to the dma_device struct which is
> associated with the dt node needs to passed as the data parameter.
> New function will use this pointer to match only channels which belong to the
> specified DMA controller.

This patch needs review by DT folks too

> 
> Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
> ---
>  drivers/dma/of-dma.c   | 35 +++++++++++++++++++++++++++++++++++
>  include/linux/of_dma.h |  4 ++++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
> index e8fe9dc..d5fbeaa 100644
> --- a/drivers/dma/of-dma.c
> +++ b/drivers/dma/of-dma.c
> @@ -218,3 +218,38 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>  			&dma_spec->args[0]);
>  }
>  EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
> +
> +/**
> + * of_dma_xlate_by_chan_id - Translate dt property to DMA channel by channel id
> + * @dma_spec:	pointer to DMA specifier as found in the device tree
> + * @of_dma:	pointer to DMA controller data
> + *
> + * This function can be used as the of xlate callback for DMA driver which wants
> + * to match the channel based on the channel id. When using this xlate function
> + * the #dma-cells propety of the DMA controller dt node needs to be set to 1.
> + * The data parameter of of_dma_controller_register must be a pointer to the
> + * dma_device struct the function should match upon.
> + *
> + * Returns pointer to appropriate dma channel on success or NULL on error.
> + */
> +struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> +					 struct of_dma *ofdma)
> +{
> +	struct dma_device *dev = ofdma->of_dma_data;
> +	struct dma_chan *chan, *candidate = NULL;
> +
> +	if (!dev || dma_spec->args_count != 1)
> +		return NULL;
> +
> +	list_for_each_entry(chan, &dev->channels, device_node)
> +		if (chan->chan_id == dma_spec->args[0]) {
> +			candidate = chan;
> +			break;
> +		}
> +
> +	if (!candidate)
> +		return NULL;
> +
> +	return dma_get_slave_channel(candidate);
> +}
> +EXPORT_SYMBOL_GPL(of_dma_xlate_by_chan_id);
> diff --git a/include/linux/of_dma.h b/include/linux/of_dma.h
> index ae36298..56bc026 100644
> --- a/include/linux/of_dma.h
> +++ b/include/linux/of_dma.h
> @@ -41,6 +41,8 @@ extern struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
>  						     const char *name);
>  extern struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
>  		struct of_dma *ofdma);
> +extern struct dma_chan *of_dma_xlate_by_chan_id(struct of_phandle_args *dma_spec,
> +		struct of_dma *ofdma);
>  #else
>  static inline int of_dma_controller_register(struct device_node *np,
>  		struct dma_chan *(*of_dma_xlate)
> @@ -66,6 +68,8 @@ static inline struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_s
>  	return NULL;
>  }
>  
> +#define of_dma_xlate_by_chan_id NULL
> +
>  #endif
>  
>  #endif /* __LINUX_OF_DMA_H */
> -- 
> 1.8.4.2
> 

-- 

[PATCH RFC v12 6/7] dma: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Alexander Popov <a13xp0p0v88-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 .../devicetree/bindings/dma/mpc512x-dma.txt        | 40 ++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 0000000..b1cbc3f
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,40 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+Required properties:
+- compatible: Should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma"
+- reg: Address and size of the DMA controller's register set
+- Interrupt for the DMA controller. Syntax of interrupt client node
+	is described in interrupt-controller/interrupts.txt
+
+Optional properties:
+- #dma-cells: The length of the DMA specifier, must be <1>.
+	Each channel of this DMA controller has a peripheral request line,
+	this assignment is fixed in hardware. The cell in dmas property
+	of a client device represents the channel number
+
+Example:
+
+	dma0: dma@14000 {
+		compatible = "fsl,mpc5121-dma";
+		reg = <0x14000 0x1800>;
+		interrupts = <65 0x8>;
+		#dma-cells = <1>;
+	};
+
+DMA clients must use the format described in dma/dma.txt
+
+Example:
+
+	sdhc@1500 {
+		compatible = "fsl,mpc5121-sdhc";
+		/* ... */
+		dmas = <&dma0 30>;
+		dma-names = "rx-tx";
+	};
-- 
1.8.4.2

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[PATCH RFC v12 6/7] dma: mpc512x: add device tree binding document

[Alexander Popov]

Introduce a device tree binding document for the MPC512x DMA controller

Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
---
 .../devicetree/bindings/dma/mpc512x-dma.txt        | 40 ++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
new file mode 100644
index 0000000..b1cbc3f
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
@@ -0,0 +1,40 @@
+* Freescale MPC512x and MPC8308 DMA Controller
+
+The DMA controller in Freescale MPC512x and MPC8308 SoCs can move
+blocks of memory contents between memory and peripherals or
+from memory to memory.
+
+Refer to "Generic DMA Controller and DMA request bindings" in
+the dma/dma.txt file for a more detailed description of binding.
+
+Required properties:
+- compatible: Should be "fsl,mpc5121-dma" or "fsl,mpc8308-dma"
+- reg: Address and size of the DMA controller's register set
+- Interrupt for the DMA controller. Syntax of interrupt client node
+	is described in interrupt-controller/interrupts.txt
+
+Optional properties:
+- #dma-cells: The length of the DMA specifier, must be <1>.
+	Each channel of this DMA controller has a peripheral request line,
+	this assignment is fixed in hardware. The cell in dmas property
+	of a client device represents the channel number
+
+Example:
+
+	dma0: dma@14000 {
+		compatible = "fsl,mpc5121-dma";
+		reg = <0x14000 0x1800>;
+		interrupts = <65 0x8>;
+		#dma-cells = <1>;
+	};
+
+DMA clients must use the format described in dma/dma.txt
+
+Example:
+
+	sdhc@1500 {
+		compatible = "fsl,mpc5121-sdhc";
+		/* ... */
+		dmas = <&dma0 30>;
+		dma-names = "rx-tx";
+	};
-- 
1.8.4.2

[PATCH RFC v12 7/7] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Alexander Popov <a13xp0p0v88-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c          | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
 			compatible = "fsl,mpc5121-dma";
 			reg = <0x14000 0x1800>;
 			interrupts = <65 0x8>;
+			#dma-cells = <1>;
 		};
 	};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index d2c5f79..fa0614e 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,6 +52,7 @@
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
+#include <linux/of_dma.h>
 #include <linux/of_platform.h>
 
 #include <linux/random.h>
@@ -1031,7 +1032,15 @@ static int mpc_dma_probe(struct platform_device *op)
 	if (retval)
 		goto err_free2;
 
-	return retval;
+	/* Register with OF helpers for DMA lookups (nonfatal) */
+	if (dev->of_node) {
+		retval = of_dma_controller_register(dev->of_node,
+						of_dma_xlate_by_chan_id, mdma);
+		if (retval)
+			dev_warn(dev, "Could not register for OF lookup\n");
+	}
+
+	return 0;
 
 err_free2:
 	if (mdma->is_mpc8308)
@@ -1052,6 +1061,8 @@ static int mpc_dma_remove(struct platform_device *op)
 	struct device *dev = &op->dev;
 	struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+	if (dev->of_node)
+		of_dma_controller_free(dev->of_node);
 	dma_async_device_unregister(&mdma->dma);
 	if (mdma->is_mpc8308) {
 		free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

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[PATCH RFC v12 7/7] dma: mpc512x: register for device tree channel lookup

[Alexander Popov]

Register the controller for device tree based lookup of DMA channels
(non-fatal for backwards compatibility with older device trees) and
provide the '#dma-cells' property in the shared mpc5121.dtsi file

Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com>
---
 arch/powerpc/boot/dts/mpc5121.dtsi |  1 +
 drivers/dma/mpc512x_dma.c          | 13 ++++++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/dts/mpc5121.dtsi b/arch/powerpc/boot/dts/mpc5121.dtsi
index 2c0e155..7f9d14f 100644
--- a/arch/powerpc/boot/dts/mpc5121.dtsi
+++ b/arch/powerpc/boot/dts/mpc5121.dtsi
@@ -498,6 +498,7 @@
 			compatible = "fsl,mpc5121-dma";
 			reg = <0x14000 0x1800>;
 			interrupts = <65 0x8>;
+			#dma-cells = <1>;
 		};
 	};
 
diff --git a/drivers/dma/mpc512x_dma.c b/drivers/dma/mpc512x_dma.c
index d2c5f79..fa0614e 100644
--- a/drivers/dma/mpc512x_dma.c
+++ b/drivers/dma/mpc512x_dma.c
@@ -52,6 +52,7 @@
 #include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
+#include <linux/of_dma.h>
 #include <linux/of_platform.h>
 
 #include <linux/random.h>
@@ -1031,7 +1032,15 @@ static int mpc_dma_probe(struct platform_device *op)
 	if (retval)
 		goto err_free2;
 
-	return retval;
+	/* Register with OF helpers for DMA lookups (nonfatal) */
+	if (dev->of_node) {
+		retval = of_dma_controller_register(dev->of_node,
+						of_dma_xlate_by_chan_id, mdma);
+		if (retval)
+			dev_warn(dev, "Could not register for OF lookup\n");
+	}
+
+	return 0;
 
 err_free2:
 	if (mdma->is_mpc8308)
@@ -1052,6 +1061,8 @@ static int mpc_dma_remove(struct platform_device *op)
 	struct device *dev = &op->dev;
 	struct mpc_dma *mdma = dev_get_drvdata(dev);
 
+	if (dev->of_node)
+		of_dma_controller_free(dev->of_node);
 	dma_async_device_unregister(&mdma->dma);
 	if (mdma->is_mpc8308) {
 		free_irq(mdma->irq2, mdma);
-- 
1.8.4.2

Re: [PATCH RFC v12 0/7] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

Hello

2014-04-23 17:53 GMT+04:00 Alexander Popov <a13xp0p0v88-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>:
> Changes in v12:
>  A new patch (part 2/7) is added to this series.
>  Part 6/7:
>  - change the description of 'compatible' property according part 2/7;
>  - improve the document according Gerhard's feedback;

Could I have a feedback? Is the binding document fine now?
Thanks!

> Alexander Popov (7):
>   dma: mpc512x: reorder mpc8308 specific instructions
>   dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308
>   dma: mpc512x: add support for peripheral transfers
>   dma: mpc512x: fix freeing resources in mpc_dma_probe() and
>     mpc_dma_remove()
>   dma: of: add common xlate function for matching by channel id
>   dma: mpc512x: add device tree binding document
>   dma: mpc512x: register for device tree channel lookup
>
>  .../devicetree/bindings/dma/mpc512x-dma.txt        |  40 +++
>  arch/powerpc/boot/dts/mpc5121.dtsi                 |   1 +
>  arch/powerpc/boot/dts/mpc8308_p1m.dts              |   2 +-
>  arch/powerpc/boot/dts/mpc8308rdb.dts               |   2 +-
>  drivers/dma/mpc512x_dma.c                          | 346 ++++++++++++++++++---
>  drivers/dma/of-dma.c                               |  35 +++
>  include/linux/of_dma.h                             |   4 +
>  7 files changed, 390 insertions(+), 40 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>
> --
> 1.8.4.2
>

Best regards,
Alexander
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Re: [PATCH RFC v12 0/7] MPC512x DMA slave s/g support, OF DMA lookup

[Alexander Popov]

Hello

2014-04-23 17:53 GMT+04:00 Alexander Popov <a13xp0p0v88@gmail.com>:
> Changes in v12:
>  A new patch (part 2/7) is added to this series.
>  Part 6/7:
>  - change the description of 'compatible' property according part 2/7;
>  - improve the document according Gerhard's feedback;

Could I have a feedback? Is the binding document fine now?
Thanks!

> Alexander Popov (7):
>   dma: mpc512x: reorder mpc8308 specific instructions
>   dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308
>   dma: mpc512x: add support for peripheral transfers
>   dma: mpc512x: fix freeing resources in mpc_dma_probe() and
>     mpc_dma_remove()
>   dma: of: add common xlate function for matching by channel id
>   dma: mpc512x: add device tree binding document
>   dma: mpc512x: register for device tree channel lookup
>
>  .../devicetree/bindings/dma/mpc512x-dma.txt        |  40 +++
>  arch/powerpc/boot/dts/mpc5121.dtsi                 |   1 +
>  arch/powerpc/boot/dts/mpc8308_p1m.dts              |   2 +-
>  arch/powerpc/boot/dts/mpc8308rdb.dts               |   2 +-
>  drivers/dma/mpc512x_dma.c                          | 346 ++++++++++++++++++---
>  drivers/dma/of-dma.c                               |  35 +++
>  include/linux/of_dma.h                             |   4 +
>  7 files changed, 390 insertions(+), 40 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>
> --
> 1.8.4.2
>

Best regards,
Alexander