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Subject[PATCH 26/63] dmaengine: ste_dma40: Supply full Device Tree parsing support
Date
Using the new DMA DT bindings and API, we can register the DMA40 driver
as Device Tree capable. Now, when a client attempts to allocate a
channel using the DMA DT bindings via its own node, we are able to parse
the request and allocate a channel in the correct manner.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <djbw@fb.com>
Cc: Per Forlin <per.forlin@stericsson.com>
Cc: Rabin Vincent <rabin@rab.in>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: devicetree-discuss@lists.ozlabs.org
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
.../devicetree/bindings/dma/ste-dma40.txt | 62 ++++++++++++++++++++
drivers/dma/ste_dma40.c | 52 ++++++++++++++++
2 files changed, 114 insertions(+)
create mode 100644 Documentation/devicetree/bindings/dma/ste-dma40.txt

diff --git a/Documentation/devicetree/bindings/dma/ste-dma40.txt b/Documentation/devicetree/bindings/dma/ste-dma40.txt
new file mode 100644
index 0000000..2679a87
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/ste-dma40.txt
@@ -0,0 +1,62 @@
+* DMA40 DMA Controller
+
+Required properties:
+- compatible: "stericsson,dma40"
+- reg: Address range of the DMAC registers
+- reg-names: Names of the above areas to use during resource look-up
+- interrupt: Should contain the DMAC interrupt number
+- #dma-cells: must be <3>
+
+Optional properties:
+- dma-channels: Number of channels supported by hardware - if not present
+ the driver will attempt to obtain the information from H/W
+
+Example:
+
+ dma: dma-controller@801C0000 {
+ compatible = "stericsson,db8500-dma40", "stericsson,dma40";
+ reg = <0x801C0000 0x1000 0x40010000 0x800>;
+ reg-names = "base", "lcpa";
+ interrupt-parent = <&intc>;
+ interrupts = <0 25 0x4>;
+
+ #dma-cells = <2>;
+ dma-channels = <8>;
+ };
+
+Clients
+Required properties:
+- dmas: Comma separated list of dma channel requests
+- dma-names: Names of the aforementioned requested channels
+
+Each dmas request consists of 4 cells:
+ 1. A phandle pointing to the DMA controller
+ 2. Device Type
+ 3. The DMA request line number (only when 'use fixed channel' is set)
+ 4. A 32bit mask specifying; mode, direction and endianess [NB: This list will grow]
+ 0x00000001: Mode:
+ Logical channel when unset
+ Physical channel when set
+ 0x00000002: Direction:
+ Memory to Device when unset
+ Device to Memory when set
+ 0x00000004: Endianess:
+ Little endian when unset
+ Big endian when set
+ 0x00000008: Use fixed channel:
+ Use automatic channel selection when unset
+ Use DMA request line number when set
+
+Example:
+
+ uart@80120000 {
+ compatible = "arm,pl011", "arm,primecell";
+ reg = <0x80120000 0x1000>;
+ interrupts = <0 11 0x4>;
+
+ dmas = <&dma 13 0 0x2>, /* Logical - DevToMem */
+ <&dma 13 0 0x0>; /* Logical - MemToDev */
+ dma-names = "rx", "rx";
+
+ status = "disabled";
+ };
diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index d7c2397..b77d508 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -18,6 +18,7 @@
#include <linux/pm_runtime.h>
#include <linux/err.h>
#include <linux/of.h>
+#include <linux/of_dma.h>
#include <linux/amba/bus.h>
#include <linux/regulator/consumer.h>
#include <linux/platform_data/dma-ste-dma40.h>
@@ -2419,6 +2420,50 @@ static void d40_set_prio_realtime(struct d40_chan *d40c)
__d40_set_prio_rt(d40c, d40c->dma_cfg.dev_type, false);
}

+#define D40_DT_FLAGS_MODE(flags) ((flags >> 0) & 0x1)
+#define D40_DT_FLAGS_DIR(flags) ((flags >> 1) & 0x1)
+#define D40_DT_FLAGS_BIG_ENDIAN(flags) ((flags >> 2) & 0x1)
+#define D40_DT_FLAGS_FIXED_CHAN(flags) ((flags >> 3) & 0x1)
+
+static struct dma_chan *d40_xlate(struct of_phandle_args *dma_spec,
+ struct of_dma *ofdma)
+{
+ struct stedma40_chan_cfg cfg;
+ dma_cap_mask_t cap;
+ u32 flags;
+
+ memset(&cfg, 0, sizeof(struct stedma40_chan_cfg));
+
+ dma_cap_zero(cap);
+ dma_cap_set(DMA_SLAVE, cap);
+
+ cfg.dev_type = dma_spec->args[0];
+ flags = dma_spec->args[2];
+
+ switch (D40_DT_FLAGS_MODE(flags)) {
+ case 0: cfg.mode = STEDMA40_MODE_LOGICAL; break;
+ case 1: cfg.mode = STEDMA40_MODE_PHYSICAL; break;
+ }
+
+ switch (D40_DT_FLAGS_DIR(flags)) {
+ case 0:
+ cfg.dir = STEDMA40_MEM_TO_PERIPH;
+ cfg.dst_info.big_endian = D40_DT_FLAGS_BIG_ENDIAN(flags);
+ break;
+ case 1:
+ cfg.dir = STEDMA40_PERIPH_TO_MEM;
+ cfg.src_info.big_endian = D40_DT_FLAGS_BIG_ENDIAN(flags);
+ break;
+ }
+
+ if (D40_DT_FLAGS_FIXED_CHAN(flags)) {
+ cfg.phy_channel = dma_spec->args[1];
+ cfg.use_fixed_channel = true;
+ }
+
+ return dma_request_channel(cap, stedma40_filter, &cfg);
+}
+
/* DMA ENGINE functions */
static int d40_alloc_chan_resources(struct dma_chan *chan)
{
@@ -3632,6 +3677,13 @@ static int __init d40_probe(struct platform_device *pdev)

d40_hw_init(base);

+ if (np) {
+ err = of_dma_controller_register(np, d40_xlate, NULL);
+ if (err && err != -ENODEV)
+ dev_err(&pdev->dev,
+ "could not register of_dma_controller\n");
+ }
+
dev_info(base->dev, "initialized\n");
return 0;

--
1.7.10.4


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