[PATCH v3 1/6] at_hdmac: move to generic DMA binding
ludovic.desroches at atmel.com
ludovic.desroches at atmel.com
Fri Apr 19 05:11:18 EDT 2013
From: Ludovic Desroches <ludovic.desroches at atmel.com>
Update at_hdmac driver to support generic DMA device tree binding. Devices
can still request channel with dma_request_channel() then it doesn't break
DMA for non DT boards.
Signed-off-by: Ludovic Desroches <ludovic.desroches at atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre at atmel.com>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
Acked-by: Arnd Bergmann <arnd at arndb.de>
---
.../devicetree/bindings/dma/atmel-dma.txt | 35 ++++++--
drivers/dma/at_hdmac.c | 93 ++++++++++++++++++++--
drivers/dma/at_hdmac_regs.h | 4 +
3 files changed, 121 insertions(+), 11 deletions(-)
diff --git a/Documentation/devicetree/bindings/dma/atmel-dma.txt b/Documentation/devicetree/bindings/dma/atmel-dma.txt
index 3c046ee..c80e8a3 100644
--- a/Documentation/devicetree/bindings/dma/atmel-dma.txt
+++ b/Documentation/devicetree/bindings/dma/atmel-dma.txt
@@ -1,14 +1,39 @@
* Atmel Direct Memory Access Controller (DMA)
Required properties:
-- compatible: Should be "atmel,<chip>-dma"
-- reg: Should contain DMA registers location and length
-- interrupts: Should contain DMA interrupt
+- compatible: Should be "atmel,<chip>-dma".
+- reg: Should contain DMA registers location and length.
+- interrupts: Should contain DMA interrupt.
+- #dma-cells: Must be <2>, used to represent the number of integer cells in
+the dmas property of client devices.
-Examples:
+Example:
-dma at ffffec00 {
+dma0: dma at ffffec00 {
compatible = "atmel,at91sam9g45-dma";
reg = <0xffffec00 0x200>;
interrupts = <21>;
+ #dma-cells = <2>;
+};
+
+DMA clients connected to the Atmel DMA controller must use the format
+described in the dma.txt file, using a three-cell specifier for each channel:
+a phandle plus two interger cells.
+The three cells in order are:
+
+1. A phandle pointing to the DMA controller.
+2. The memory interface (16 most significant bits), the peripheral interface
+(16 less significant bits).
+3. The peripheral identifier for the hardware handshaking interface. The
+identifier can be different for tx and rx.
+
+Example:
+
+i2c0 at i2c@f8010000 {
+ compatible = "atmel,at91sam9x5-i2c";
+ reg = <0xf8010000 0x100>;
+ interrupts = <9 4 6>;
+ dmas = <&dma0 1 7>,
+ <&dma0 1 8>;
+ dma-names = "tx", "rx";
};
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index de4e930..fda2661 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -24,6 +24,7 @@
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <linux/of_dma.h>
#include "at_hdmac_regs.h"
#include "dmaengine.h"
@@ -677,7 +678,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
ctrlb |= ATC_DST_ADDR_MODE_FIXED
| ATC_SRC_ADDR_MODE_INCR
| ATC_FC_MEM2PER
- | ATC_SIF(AT_DMA_MEM_IF) | ATC_DIF(AT_DMA_PER_IF);
+ | ATC_SIF(atchan->mem_if) | ATC_DIF(atchan->per_if);
reg = sconfig->dst_addr;
for_each_sg(sgl, sg, sg_len, i) {
struct at_desc *desc;
@@ -716,7 +717,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
ctrlb |= ATC_DST_ADDR_MODE_INCR
| ATC_SRC_ADDR_MODE_FIXED
| ATC_FC_PER2MEM
- | ATC_SIF(AT_DMA_PER_IF) | ATC_DIF(AT_DMA_MEM_IF);
+ | ATC_SIF(atchan->per_if) | ATC_DIF(atchan->mem_if);
reg = sconfig->src_addr;
for_each_sg(sgl, sg, sg_len, i) {
@@ -822,8 +823,8 @@ atc_dma_cyclic_fill_desc(struct dma_chan *chan, struct at_desc *desc,
desc->lli.ctrlb = ATC_DST_ADDR_MODE_FIXED
| ATC_SRC_ADDR_MODE_INCR
| ATC_FC_MEM2PER
- | ATC_SIF(AT_DMA_MEM_IF)
- | ATC_DIF(AT_DMA_PER_IF);
+ | ATC_SIF(atchan->mem_if)
+ | ATC_DIF(atchan->per_if);
break;
case DMA_DEV_TO_MEM:
@@ -833,8 +834,8 @@ atc_dma_cyclic_fill_desc(struct dma_chan *chan, struct at_desc *desc,
desc->lli.ctrlb = ATC_DST_ADDR_MODE_INCR
| ATC_SRC_ADDR_MODE_FIXED
| ATC_FC_PER2MEM
- | ATC_SIF(AT_DMA_PER_IF)
- | ATC_DIF(AT_DMA_MEM_IF);
+ | ATC_SIF(atchan->per_if)
+ | ATC_DIF(atchan->mem_if);
break;
default:
@@ -1190,6 +1191,67 @@ static void atc_free_chan_resources(struct dma_chan *chan)
dev_vdbg(chan2dev(chan), "free_chan_resources: done\n");
}
+#ifdef CONFIG_OF
+static bool at_dma_filter(struct dma_chan *chan, void *slave)
+{
+ struct at_dma_slave *atslave = slave;
+
+ if (atslave->dma_dev == chan->device->dev) {
+ chan->private = atslave;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *of_dma)
+{
+ struct dma_chan *chan;
+ struct at_dma_chan *atchan;
+ struct at_dma_slave *atslave;
+ dma_cap_mask_t mask;
+ unsigned int per_id;
+ struct platform_device *dmac_pdev;
+
+ if (dma_spec->args_count != 2)
+ return NULL;
+
+ dmac_pdev = of_find_device_by_node(dma_spec->np);
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ atslave = devm_kzalloc(&dmac_pdev->dev, sizeof(*atslave), GFP_KERNEL);
+ if (!atslave)
+ return NULL;
+ /*
+ * We can fill both SRC_PER and DST_PER, one of these fields will be
+ * ignored depending on DMA transfer direction.
+ */
+ per_id = dma_spec->args[1];
+ atslave->cfg = ATC_FIFOCFG_HALFFIFO | ATC_DST_H2SEL_HW
+ | ATC_SRC_H2SEL_HW | ATC_DST_PER(per_id)
+ | ATC_SRC_PER(per_id);
+ atslave->dma_dev = &dmac_pdev->dev;
+
+ chan = dma_request_channel(mask, at_dma_filter, atslave);
+ if (!chan)
+ return NULL;
+
+ atchan = to_at_dma_chan(chan);
+ atchan->per_if = dma_spec->args[0] & 0xff;
+ atchan->mem_if = (dma_spec->args[0] >> 16) & 0xff;
+
+ return chan;
+}
+#else
+static struct dma_chan *at_dma_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *of_dma)
+{
+ return NULL;
+}
+#endif
/*-- Module Management -----------------------------------------------*/
@@ -1344,6 +1406,8 @@ static int __init at_dma_probe(struct platform_device *pdev)
for (i = 0; i < plat_dat->nr_channels; i++) {
struct at_dma_chan *atchan = &atdma->chan[i];
+ atchan->mem_if = AT_DMA_MEM_IF;
+ atchan->per_if = AT_DMA_PER_IF;
atchan->chan_common.device = &atdma->dma_common;
dma_cookie_init(&atchan->chan_common);
list_add_tail(&atchan->chan_common.device_node,
@@ -1390,8 +1454,25 @@ static int __init at_dma_probe(struct platform_device *pdev)
dma_async_device_register(&atdma->dma_common);
+ /*
+ * Do not return an error if the dmac node is not present in order to
+ * not break the existing way of requesting channel with
+ * dma_request_channel().
+ */
+ if (pdev->dev.of_node) {
+ err = of_dma_controller_register(pdev->dev.of_node,
+ at_dma_xlate, atdma);
+ if (err) {
+ dev_err(&pdev->dev, "could not register of_dma_controller\n");
+ goto err_of_dma_controller_register;
+ }
+ }
+
return 0;
+err_of_dma_controller_register:
+ dma_async_device_unregister(&atdma->dma_common);
+ dma_pool_destroy(atdma->dma_desc_pool);
err_pool_create:
platform_set_drvdata(pdev, NULL);
free_irq(platform_get_irq(pdev, 0), atdma);
diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
index 0eb3c13..c604d26 100644
--- a/drivers/dma/at_hdmac_regs.h
+++ b/drivers/dma/at_hdmac_regs.h
@@ -220,6 +220,8 @@ enum atc_status {
* @device: parent device
* @ch_regs: memory mapped register base
* @mask: channel index in a mask
+ * @per_if: peripheral interface
+ * @mem_if: memory interface
* @status: transmit status information from irq/prep* functions
* to tasklet (use atomic operations)
* @tasklet: bottom half to finish transaction work
@@ -238,6 +240,8 @@ struct at_dma_chan {
struct at_dma *device;
void __iomem *ch_regs;
u8 mask;
+ u8 per_if;
+ u8 mem_if;
unsigned long status;
struct tasklet_struct tasklet;
u32 save_cfg;
--
1.7.11.3
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