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Message-ID: <20130418121253.GF27903@gmail.com>
Date: Thu, 18 Apr 2013 13:12:53 +0100
From: Lee Jones <lee.jones@...aro.org>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: arnd@...db.de, linus.walleij@...ricsson.com,
Vinod Koul <vinod.koul@...el.com>, Dan Williams <djbw@...com>,
Per Forlin <per.forlin@...ricsson.com>,
Rabin Vincent <rabin@....in>
Subject: [PATCH 24/32 v2] dmaengine: ste_dma40: Supply full Device Tree
parsing support
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@...el.com>
Cc: Dan Williams <djbw@...com>
Cc: Per Forlin <per.forlin@...ricsson.com>
Cc: Rabin Vincent <rabin@....in>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
diff --git a/Documentation/devicetree/bindings/dma/ste-dma40.txt b/Documentation/devicetree/bindings/dma/ste-dma40.txt
new file mode 100644
index 0000000..0aca55f
--- /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@...C0000 {
+ 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]
+ bit 1: Mode:
+ 0: Logical
+ 1: Physical
+ bit 2: Direction:
+ 0: Mem to Mem
+ 1: Mem to Dev
+ bit 3: Endianess:
+ 0: Little endian
+ 1: Big endian
+ bit 4: Use fixed channel:
+ 0: Use automatic channel selection
+ 1: Use DMA request line number
+
+Example:
+
+ uart@...20000 {
+ compatible = "arm,pl011", "arm,primecell";
+ reg = <0x80120000 0x1000>;
+ interrupts = <0 11 0x4>;
+
+ dmas = <&dma 13 0 0x8>, /* Logical - DevToMem */
+ <&dma 13 0 0x4>; /* Logical - MemToDev */
+ dma-names = "rx", "rx";
+
+ status = "disabled";
+ };
diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index c70660d..f551b27 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>
@@ -2409,6 +2410,53 @@ 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;
+ default:
+ pr_err("dma40: Unknown mode read from DT (%d)\n",
+ D40_DT_FLAGS_MODE(flags));
+ return NULL;
+ }
+
+ switch (D40_DT_FLAGS_DIR(flags)) {
+ case 0: cfg.dir = STEDMA40_MEM_TO_MEM; break;
+ case 1: cfg.dir = STEDMA40_MEM_TO_PERIPH; break;
+ }
+
+ if (cfg.dir == STEDMA40_PERIPH_TO_MEM)
+ cfg.src_info.big_endian = D40_DT_FLAGS_BIG_ENDIAN(flags);
+ if (cfg.dir == STEDMA40_MEM_TO_PERIPH)
+ cfg.dst_info.big_endian = D40_DT_FLAGS_BIG_ENDIAN(flags);
+
+ 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)
{
@@ -3615,6 +3663,13 @@ 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;
--
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