[PATCH v10 0/2] Add support for the Allwinner A31 DMA Controller

[PATCH v10 0/2] Add support for the Allwinner A31 DMA Controller

[Maxime Ripard]

Hi,

This patchset adds support for the DMA controller found in the
Allwinner A31 and A23 SoCs.

This has been tested using the newly introduced SPI driver on an A31
EVK. Support for DMA-driven SPI transfers will be the subject of
another patch serie.

Thanks,
Maxime

Changes from v9:
  - Rebased on top of 3.16-rc1
  - Fixed the whitespace error in the documentation

Changes from v8:
  - Drop the select on DMA_OF
  - Depend on COMPILE_TEST to get more build tests coverage

Changes from v7:
  - select DMA_OF, since we're only relying on DT
  - Properly kill the tasklet as suggested in
    https://lwn.net/Articles/588457/
  - Split up the dt bindings documentation into a separate patch

Changes from v6:
  - Dropped the merged patches and the clock patches that are pretty
    orthogonal to this driver

Changes from v5:
  - Rebased on top of 3.15-rc1

Changes from v4:
  - Removed the packed attribute on the LLI
  - Switched to using a NULL device pointer in clk_get on PLL6 and
    AHB1 mux to make explicit that we are getting global clocks
  - Switched from spin_lock_irqsave to spin_lock in the interrupt
    handler
  - Various nitpicks from Andy Shevchenko:
    + Switched to using %p printk formats for pointers
    + Inverted some tests to lose a level of indentation
    + Dropped ifdef DEBUG protecting calls to dev_dbg

Changes from v3:
  - A few other comments made by Andy Shevchenko were fixed:
    + Used references in %pa* printk formats
    + Used is_slave_direction in prep_slave_sg to make sure we were
      actually called for something, and to avoid making assumptions
      that we were actually called with the expected directions
    + A few others minor fixes: s/pr_err/dev_err/, etc.

Changes from v2:
  - Removed the clk_put calls in the clock protection functions
  - Splitted out the sunxi machines into several files
  - Moved the clock protection code into these new machine files
  - Moved the PLL6 reparenting to the DMA driver
  - Addressed various comments from Andy Shevchenko: switched to using
    devm_kcalloc, used correct printk formats for physical and DMA
    addresses, etc.

Changes from v1:
  - Removed the clk_put call in the clocks protecting patches
  - Minor fixes here and there as suggested by Andy Shevchenko: switch
    to dmam_pool_create, switch to dev_dbg instead of pr_debug, etc.


Maxime Ripard (2):
  Documentation: dt: Add Allwinner A31 DMA controller bindings
  dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

 .../devicetree/bindings/dma/sun6i-dma.txt          |   45 +
 drivers/dma/Kconfig                                |    8 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/sun6i-dma.c                            | 1058 ++++++++++++++++++++
 4 files changed, 1112 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/sun6i-dma.txt
 create mode 100644 drivers/dma/sun6i-dma.c

-- 
2.0.0

[PATCH v10 0/2] Add support for the Allwinner A31 DMA Controller

[Maxime Ripard]

Hi,

This patchset adds support for the DMA controller found in the
Allwinner A31 and A23 SoCs.

This has been tested using the newly introduced SPI driver on an A31
EVK. Support for DMA-driven SPI transfers will be the subject of
another patch serie.

Thanks,
Maxime

Changes from v9:
  - Rebased on top of 3.16-rc1
  - Fixed the whitespace error in the documentation

Changes from v8:
  - Drop the select on DMA_OF
  - Depend on COMPILE_TEST to get more build tests coverage

Changes from v7:
  - select DMA_OF, since we're only relying on DT
  - Properly kill the tasklet as suggested in
    https://lwn.net/Articles/588457/
  - Split up the dt bindings documentation into a separate patch

Changes from v6:
  - Dropped the merged patches and the clock patches that are pretty
    orthogonal to this driver

Changes from v5:
  - Rebased on top of 3.15-rc1

Changes from v4:
  - Removed the packed attribute on the LLI
  - Switched to using a NULL device pointer in clk_get on PLL6 and
    AHB1 mux to make explicit that we are getting global clocks
  - Switched from spin_lock_irqsave to spin_lock in the interrupt
    handler
  - Various nitpicks from Andy Shevchenko:
    + Switched to using %p printk formats for pointers
    + Inverted some tests to lose a level of indentation
    + Dropped ifdef DEBUG protecting calls to dev_dbg

Changes from v3:
  - A few other comments made by Andy Shevchenko were fixed:
    + Used references in %pa* printk formats
    + Used is_slave_direction in prep_slave_sg to make sure we were
      actually called for something, and to avoid making assumptions
      that we were actually called with the expected directions
    + A few others minor fixes: s/pr_err/dev_err/, etc.

Changes from v2:
  - Removed the clk_put calls in the clock protection functions
  - Splitted out the sunxi machines into several files
  - Moved the clock protection code into these new machine files
  - Moved the PLL6 reparenting to the DMA driver
  - Addressed various comments from Andy Shevchenko: switched to using
    devm_kcalloc, used correct printk formats for physical and DMA
    addresses, etc.

Changes from v1:
  - Removed the clk_put call in the clocks protecting patches
  - Minor fixes here and there as suggested by Andy Shevchenko: switch
    to dmam_pool_create, switch to dev_dbg instead of pr_debug, etc.


Maxime Ripard (2):
  Documentation: dt: Add Allwinner A31 DMA controller bindings
  dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

 .../devicetree/bindings/dma/sun6i-dma.txt          |   45 +
 drivers/dma/Kconfig                                |    8 +
 drivers/dma/Makefile                               |    1 +
 drivers/dma/sun6i-dma.c                            | 1058 ++++++++++++++++++++
 4 files changed, 1112 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/sun6i-dma.txt
 create mode 100644 drivers/dma/sun6i-dma.c

-- 
2.0.0

[PATCH v10 1/2] Documentation: dt: Add Allwinner A31 DMA controller bindings

[Maxime Ripard]

The Allwinner A31 DMA controller is rather simple to describe in the DT. Add
the bindings documentation.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 .../devicetree/bindings/dma/sun6i-dma.txt          | 45 ++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/sun6i-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/sun6i-dma.txt b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
new file mode 100644
index 000000000000..3e145c1675b1
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
@@ -0,0 +1,45 @@
+Allwinner A31 DMA Controller
+
+This driver follows the generic DMA bindings defined in dma.txt.
+
+Required properties:
+
+- compatible:	Must be "allwinner,sun6i-a31-dma"
+- reg:		Should contain the registers base address and length
+- interrupts:	Should contain a reference to the interrupt used by this device
+- clocks:	Should contain a reference to the parent AHB clock
+- resets:	Should contain a reference to the reset controller asserting
+		this device in reset
+- #dma-cells :	Should be 1, a single cell holding a line request number
+
+Example:
+	dma: dma-controller@01c02000 {
+		compatible = "allwinner,sun6i-a31-dma";
+		reg = <0x01c02000 0x1000>;
+		interrupts = <0 50 4>;
+		clocks = <&ahb1_gates 6>;
+		resets = <&ahb1_rst 6>;
+		#dma-cells = <1>;
+	};
+
+Clients:
+
+DMA clients connected to the A31 DMA controller must use the format
+described in the dma.txt file, using a two-cell specifier for each
+channel: a phandle plus one integer cells.
+The two cells in order are:
+
+1. A phandle pointing to the DMA controller.
+2. The port ID as specified in the datasheet
+
+Example:
+spi2: spi@01c6a000 {
+	compatible = "allwinner,sun6i-a31-spi";
+	reg = <0x01c6a000 0x1000>;
+	interrupts = <0 67 4>;
+	clocks = <&ahb1_gates 22>, <&spi2_clk>;
+	clock-names = "ahb", "mod";
+	dmas = <&dma 25>, <&dma 25>;
+	dma-names = "rx", "tx";
+	resets = <&ahb1_rst 22>;
+};
-- 
2.0.0

[PATCH v10 1/2] Documentation: dt: Add Allwinner A31 DMA controller bindings

[Maxime Ripard]

The Allwinner A31 DMA controller is rather simple to describe in the DT. Add
the bindings documentation.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 .../devicetree/bindings/dma/sun6i-dma.txt          | 45 ++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/dma/sun6i-dma.txt

diff --git a/Documentation/devicetree/bindings/dma/sun6i-dma.txt b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
new file mode 100644
index 000000000000..3e145c1675b1
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/sun6i-dma.txt
@@ -0,0 +1,45 @@
+Allwinner A31 DMA Controller
+
+This driver follows the generic DMA bindings defined in dma.txt.
+
+Required properties:
+
+- compatible:	Must be "allwinner,sun6i-a31-dma"
+- reg:		Should contain the registers base address and length
+- interrupts:	Should contain a reference to the interrupt used by this device
+- clocks:	Should contain a reference to the parent AHB clock
+- resets:	Should contain a reference to the reset controller asserting
+		this device in reset
+- #dma-cells :	Should be 1, a single cell holding a line request number
+
+Example:
+	dma: dma-controller at 01c02000 {
+		compatible = "allwinner,sun6i-a31-dma";
+		reg = <0x01c02000 0x1000>;
+		interrupts = <0 50 4>;
+		clocks = <&ahb1_gates 6>;
+		resets = <&ahb1_rst 6>;
+		#dma-cells = <1>;
+	};
+
+Clients:
+
+DMA clients connected to the A31 DMA controller must use the format
+described in the dma.txt file, using a two-cell specifier for each
+channel: a phandle plus one integer cells.
+The two cells in order are:
+
+1. A phandle pointing to the DMA controller.
+2. The port ID as specified in the datasheet
+
+Example:
+spi2: spi at 01c6a000 {
+	compatible = "allwinner,sun6i-a31-spi";
+	reg = <0x01c6a000 0x1000>;
+	interrupts = <0 67 4>;
+	clocks = <&ahb1_gates 22>, <&spi2_clk>;
+	clock-names = "ahb", "mod";
+	dmas = <&dma 25>, <&dma 25>;
+	dma-names = "rx", "tx";
+	resets = <&ahb1_rst 22>;
+};
-- 
2.0.0

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

The Allwinner A31 has a 16 channels DMA controller that it shares with the
newer A23. Although sharing some similarities with the DMA controller of the
older Allwinner SoCs, it's significantly different, I don't expect it to be
possible to share the driver for these two.

The A31 Controller is able to memory-to-memory or memory-to-device transfers on
the 16 channels in parallel.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/dma/Kconfig     |    8 +
 drivers/dma/Makefile    |    1 +
 drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1067 insertions(+)
 create mode 100644 drivers/dma/sun6i-dma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 1eca7b9760e6..4b439270fb11 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -375,6 +375,14 @@ config XILINX_VDMA
 	  channels, Memory Mapped to Stream (MM2S) and Stream to
 	  Memory Mapped (S2MM) for the data transfers.
 
+config DMA_SUN6I
+	tristate "Allwinner A31 SoCs DMA support"
+	depends on MACH_SUN6I || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Support for the DMA engine for Allwinner A31 SoCs.
+
 config DMA_ENGINE
 	bool
 
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index c779e1eb2db2..6807c50214c6 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -47,3 +47,4 @@ obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
 obj-$(CONFIG_FSL_EDMA) += fsl-edma.o
 obj-$(CONFIG_QCOM_BAM_DMA) += qcom_bam_dma.o
 obj-y += xilinx/
+obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
new file mode 100644
index 000000000000..8e82694f6dc4
--- /dev/null
+++ b/drivers/dma/sun6i-dma.c
@@ -0,0 +1,1058 @@
+/*
+ * Copyright (C) 2013-2014 Allwinner Tech Co., Ltd
+ * Author: Sugar <shuge@allwinnertech.com>
+ *
+ * Copyright (C) 2014 Maxime Ripard
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "virt-dma.h"
+
+/*
+ * There's 16 physical channels that can work in parallel.
+ *
+ * However we have 30 different endpoints for our requests.
+ *
+ * Since the channels are able to handle only an unidirectional
+ * transfer, we need to allocate more virtual channels so that
+ * everyone can grab one channel.
+ *
+ * Some devices can't work in both direction (mostly because it
+ * wouldn't make sense), so we have a bit fewer virtual channels than
+ * 2 channels per endpoints.
+ */
+
+#define NR_MAX_CHANNELS		16
+#define NR_MAX_REQUESTS		30
+#define NR_MAX_VCHANS		53
+
+/*
+ * Common registers
+ */
+#define DMA_IRQ_EN(x)		((x) * 0x04)
+#define DMA_IRQ_HALF			BIT(0)
+#define DMA_IRQ_PKG			BIT(1)
+#define DMA_IRQ_QUEUE			BIT(2)
+
+#define DMA_IRQ_CHAN_NR			8
+#define DMA_IRQ_CHAN_WIDTH		4
+
+
+#define DMA_IRQ_STAT(x)		((x) * 0x04 + 0x10)
+
+#define DMA_STAT		0x30
+
+/*
+ * Channels specific registers
+ */
+#define DMA_CHAN_ENABLE		0x00
+#define DMA_CHAN_ENABLE_START		BIT(0)
+#define DMA_CHAN_ENABLE_STOP		0
+
+#define DMA_CHAN_PAUSE		0x04
+#define DMA_CHAN_PAUSE_PAUSE		BIT(1)
+#define DMA_CHAN_PAUSE_RESUME		0
+
+#define DMA_CHAN_LLI_ADDR	0x08
+
+#define DMA_CHAN_CUR_CFG	0x0c
+#define DMA_CHAN_CFG_SRC_DRQ(x)		((x) & 0x1f)
+#define DMA_CHAN_CFG_SRC_IO_MODE	BIT(5)
+#define DMA_CHAN_CFG_SRC_LINEAR_MODE	(0 << 5)
+#define DMA_CHAN_CFG_SRC_BURST(x)	(((x) & 0x3) << 7)
+#define DMA_CHAN_CFG_SRC_WIDTH(x)	(((x) & 0x3) << 9)
+
+#define DMA_CHAN_CFG_DST_DRQ(x)		(DMA_CHAN_CFG_SRC_DRQ(x) << 16)
+#define DMA_CHAN_CFG_DST_IO_MODE	(DMA_CHAN_CFG_SRC_IO_MODE << 16)
+#define DMA_CHAN_CFG_DST_LINEAR_MODE	(DMA_CHAN_CFG_SRC_LINEAR_MODE << 16)
+#define DMA_CHAN_CFG_DST_BURST(x)	(DMA_CHAN_CFG_SRC_BURST(x) << 16)
+#define DMA_CHAN_CFG_DST_WIDTH(x)	(DMA_CHAN_CFG_SRC_WIDTH(x) << 16)
+
+#define DMA_CHAN_CUR_SRC	0x10
+
+#define DMA_CHAN_CUR_DST	0x14
+
+#define DMA_CHAN_CUR_CNT	0x18
+
+#define DMA_CHAN_CUR_PARA	0x1c
+
+
+/*
+ * Various hardware related defines
+ */
+#define LLI_LAST_ITEM	0xfffff800
+#define NORMAL_WAIT	8
+#define DRQ_SDRAM	1
+
+/*
+ * Hardware representation of the LLI
+ *
+ * The hardware will be fed the physical address of this structure,
+ * and read its content in order to start the transfer.
+ */
+struct sun6i_dma_lli {
+	u32			cfg;
+	u32			src;
+	u32			dst;
+	u32			len;
+	u32			para;
+	u32			p_lli_next;
+
+	/*
+	 * This field is not used by the DMA controller, but will be
+	 * used by the CPU to go through the list (mostly for dumping
+	 * or freeing it).
+	 */
+	struct sun6i_dma_lli	*v_lli_next;
+};
+
+
+struct sun6i_desc {
+	struct virt_dma_desc	vd;
+	dma_addr_t		p_lli;
+	struct sun6i_dma_lli	*v_lli;
+};
+
+struct sun6i_pchan {
+	u32			idx;
+	void __iomem		*base;
+	struct sun6i_vchan	*vchan;
+	struct sun6i_desc	*desc;
+	struct sun6i_desc	*done;
+};
+
+struct sun6i_vchan {
+	struct virt_dma_chan	vc;
+	struct list_head	node;
+	struct dma_slave_config	cfg;
+	struct sun6i_pchan	*phy;
+	u8			port;
+};
+
+struct sun6i_dma_dev {
+	struct dma_device	slave;
+	void __iomem		*base;
+	struct clk		*clk;
+	int			irq;
+	spinlock_t		lock;
+	struct reset_control	*rstc;
+	struct tasklet_struct	task;
+	atomic_t		tasklet_shutdown;
+	struct list_head	pending;
+	struct dma_pool		*pool;
+	struct sun6i_pchan	*pchans;
+	struct sun6i_vchan	*vchans;
+};
+
+static struct device *chan2dev(struct dma_chan *chan)
+{
+	return &chan->dev->device;
+}
+
+static inline struct sun6i_dma_dev *to_sun6i_dma_dev(struct dma_device *d)
+{
+	return container_of(d, struct sun6i_dma_dev, slave);
+}
+
+static inline struct sun6i_vchan *to_sun6i_vchan(struct dma_chan *chan)
+{
+	return container_of(chan, struct sun6i_vchan, vc.chan);
+}
+
+static inline struct sun6i_desc *
+to_sun6i_desc(struct dma_async_tx_descriptor *tx)
+{
+	return container_of(tx, struct sun6i_desc, vd.tx);
+}
+
+static inline void sun6i_dma_dump_com_regs(struct sun6i_dma_dev *sdev)
+{
+	dev_dbg(sdev->slave.dev, "Common register:\n"
+		"\tmask0(%04x): 0x%08x\n"
+		"\tmask1(%04x): 0x%08x\n"
+		"\tpend0(%04x): 0x%08x\n"
+		"\tpend1(%04x): 0x%08x\n"
+		"\tstats(%04x): 0x%08x\n",
+		DMA_IRQ_EN(0), readl(sdev->base + DMA_IRQ_EN(0)),
+		DMA_IRQ_EN(1), readl(sdev->base + DMA_IRQ_EN(1)),
+		DMA_IRQ_STAT(0), readl(sdev->base + DMA_IRQ_STAT(0)),
+		DMA_IRQ_STAT(1), readl(sdev->base + DMA_IRQ_STAT(1)),
+		DMA_STAT, readl(sdev->base + DMA_STAT));
+}
+
+static inline void sun6i_dma_dump_chan_regs(struct sun6i_dma_dev *sdev,
+					    struct sun6i_pchan *pchan)
+{
+	phys_addr_t reg = __virt_to_phys((unsigned long)pchan->base);
+
+	dev_dbg(sdev->slave.dev, "Chan %d reg: %pa\n"
+		"\t___en(%04x): \t0x%08x\n"
+		"\tpause(%04x): \t0x%08x\n"
+		"\tstart(%04x): \t0x%08x\n"
+		"\t__cfg(%04x): \t0x%08x\n"
+		"\t__src(%04x): \t0x%08x\n"
+		"\t__dst(%04x): \t0x%08x\n"
+		"\tcount(%04x): \t0x%08x\n"
+		"\t_para(%04x): \t0x%08x\n\n",
+		pchan->idx, &reg,
+		DMA_CHAN_ENABLE,
+		readl(pchan->base + DMA_CHAN_ENABLE),
+		DMA_CHAN_PAUSE,
+		readl(pchan->base + DMA_CHAN_PAUSE),
+		DMA_CHAN_LLI_ADDR,
+		readl(pchan->base + DMA_CHAN_LLI_ADDR),
+		DMA_CHAN_CUR_CFG,
+		readl(pchan->base + DMA_CHAN_CUR_CFG),
+		DMA_CHAN_CUR_SRC,
+		readl(pchan->base + DMA_CHAN_CUR_SRC),
+		DMA_CHAN_CUR_DST,
+		readl(pchan->base + DMA_CHAN_CUR_DST),
+		DMA_CHAN_CUR_CNT,
+		readl(pchan->base + DMA_CHAN_CUR_CNT),
+		DMA_CHAN_CUR_PARA,
+		readl(pchan->base + DMA_CHAN_CUR_PARA));
+}
+
+static inline int convert_burst(u32 maxburst, u8 *burst)
+{
+	switch (maxburst) {
+	case 1:
+		*burst = 0;
+		break;
+	case 8:
+		*burst = 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline int convert_buswidth(enum dma_slave_buswidth addr_width, u8 *width)
+{
+	switch (addr_width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		*width = 0;
+		break;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		*width = 1;
+		break;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		*width = 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void *sun6i_dma_lli_add(struct sun6i_dma_lli *prev,
+			       struct sun6i_dma_lli *next,
+			       dma_addr_t next_phy,
+			       struct sun6i_desc *txd)
+{
+	if ((!prev && !txd) || !next)
+		return NULL;
+
+	if (!prev) {
+		txd->p_lli = next_phy;
+		txd->v_lli = next;
+	} else {
+		prev->p_lli_next = next_phy;
+		prev->v_lli_next = next;
+	}
+
+	next->p_lli_next = LLI_LAST_ITEM;
+	next->v_lli_next = NULL;
+
+	return next;
+}
+
+static inline int sun6i_dma_cfg_lli(struct sun6i_dma_lli *lli,
+				    dma_addr_t src,
+				    dma_addr_t dst, u32 len,
+				    struct dma_slave_config *config)
+{
+	u8 src_width, dst_width, src_burst, dst_burst;
+	int ret;
+
+	if (!config)
+		return -EINVAL;
+
+	ret = convert_burst(config->src_maxburst, &src_burst);
+	if (ret)
+		return ret;
+
+	ret = convert_burst(config->dst_maxburst, &dst_burst);
+	if (ret)
+		return ret;
+
+	ret = convert_buswidth(config->src_addr_width, &src_width);
+	if (ret)
+		return ret;
+
+	ret = convert_buswidth(config->dst_addr_width, &dst_width);
+	if (ret)
+		return ret;
+
+	lli->cfg = DMA_CHAN_CFG_SRC_BURST(src_burst) |
+		DMA_CHAN_CFG_SRC_WIDTH(src_width) |
+		DMA_CHAN_CFG_DST_BURST(dst_burst) |
+		DMA_CHAN_CFG_DST_WIDTH(dst_width);
+
+	lli->src = src;
+	lli->dst = dst;
+	lli->len = len;
+	lli->para = NORMAL_WAIT;
+
+	return 0;
+}
+
+static inline void sun6i_dma_dump_lli(struct sun6i_vchan *vchan,
+				      struct sun6i_dma_lli *lli)
+{
+	phys_addr_t p_lli = __virt_to_phys((unsigned long)lli);
+
+	dev_dbg(chan2dev(&vchan->vc.chan),
+		"\n\tdesc:   p - %pa v - 0x%p\n"
+		"\t\tc - 0x%08x s - 0x%08x d - 0x%08x\n"
+		"\t\tl - 0x%08x p - 0x%08x n - 0x%08x\n",
+		&p_lli, lli,
+		lli->cfg, lli->src, lli->dst,
+		lli->len, lli->para, lli->p_lli_next);
+}
+
+static void sun6i_dma_free_desc(struct virt_dma_desc *vd)
+{
+	struct sun6i_desc *txd = to_sun6i_desc(&vd->tx);
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vd->tx.chan->device);
+	struct sun6i_dma_lli *v_lli, *v_next;
+	dma_addr_t p_lli, p_next;
+
+	if (unlikely(!txd))
+		return;
+
+	p_lli = txd->p_lli;
+	v_lli = txd->v_lli;
+
+	while (v_lli) {
+		v_next = v_lli->v_lli_next;
+		p_next = v_lli->p_lli_next;
+
+		dma_pool_free(sdev->pool, v_lli, p_lli);
+
+		v_lli = v_next;
+		p_lli = p_next;
+	}
+
+	kfree(txd);
+}
+
+static int sun6i_dma_terminate_all(struct sun6i_vchan *vchan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vchan->vc.chan.device);
+	struct sun6i_pchan *pchan = vchan->phy;
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock(&sdev->lock);
+	list_del_init(&vchan->node);
+	spin_unlock(&sdev->lock);
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	vchan_get_all_descriptors(&vchan->vc, &head);
+
+	if (pchan) {
+		writel(DMA_CHAN_ENABLE_STOP, pchan->base + DMA_CHAN_ENABLE);
+		writel(DMA_CHAN_PAUSE_RESUME, pchan->base + DMA_CHAN_PAUSE);
+
+		vchan->phy = NULL;
+		pchan->vchan = NULL;
+		pchan->desc = NULL;
+		pchan->done = NULL;
+	}
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	vchan_dma_desc_free_list(&vchan->vc, &head);
+
+	return 0;
+}
+
+static int sun6i_dma_start_desc(struct sun6i_vchan *vchan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vchan->vc.chan.device);
+	struct virt_dma_desc *desc = vchan_next_desc(&vchan->vc);
+	struct sun6i_pchan *pchan = vchan->phy;
+	u32 irq_val, irq_reg, irq_offset;
+
+	if (!pchan)
+		return -EAGAIN;
+
+	if (!desc) {
+		pchan->desc = NULL;
+		pchan->done = NULL;
+		return -EAGAIN;
+	}
+
+	list_del(&desc->node);
+
+	pchan->desc = to_sun6i_desc(&desc->tx);
+	pchan->done = NULL;
+
+	sun6i_dma_dump_lli(vchan, pchan->desc->v_lli);
+
+	irq_reg = pchan->idx / DMA_IRQ_CHAN_NR;
+	irq_offset = pchan->idx % DMA_IRQ_CHAN_NR;
+
+	irq_val = readl(sdev->base + DMA_IRQ_EN(irq_offset));
+	irq_val |= DMA_IRQ_QUEUE << (irq_offset * DMA_IRQ_CHAN_WIDTH);
+	writel(irq_val, sdev->base + DMA_IRQ_EN(irq_offset));
+
+	writel(pchan->desc->p_lli, pchan->base + DMA_CHAN_LLI_ADDR);
+	writel(DMA_CHAN_ENABLE_START, pchan->base + DMA_CHAN_ENABLE);
+
+	sun6i_dma_dump_com_regs(sdev);
+	sun6i_dma_dump_chan_regs(sdev, pchan);
+
+	return 0;
+}
+
+static void sun6i_dma_tasklet(unsigned long data)
+{
+	struct sun6i_dma_dev *sdev = (struct sun6i_dma_dev *)data;
+	struct sun6i_vchan *vchan;
+	struct sun6i_pchan *pchan;
+	unsigned int pchan_alloc = 0;
+	unsigned int pchan_idx;
+
+	list_for_each_entry(vchan, &sdev->slave.channels, vc.chan.device_node) {
+		spin_lock_irq(&vchan->vc.lock);
+
+		pchan = vchan->phy;
+
+		if (pchan && pchan->done) {
+			if (sun6i_dma_start_desc(vchan)) {
+				/*
+				 * No current txd associated with this channel
+				 */
+				dev_dbg(sdev->slave.dev, "pchan %u: free\n",
+					pchan->idx);
+
+				/* Mark this channel free */
+				vchan->phy = NULL;
+				pchan->vchan = NULL;
+			}
+		}
+		spin_unlock_irq(&vchan->vc.lock);
+	}
+
+	spin_lock_irq(&sdev->lock);
+	for (pchan_idx = 0; pchan_idx < NR_MAX_CHANNELS; pchan_idx++) {
+		pchan = &sdev->pchans[pchan_idx];
+
+		if (pchan->vchan || list_empty(&sdev->pending))
+			continue;
+
+		vchan = list_first_entry(&sdev->pending,
+					 struct sun6i_vchan, node);
+
+		/* Remove from pending channels */
+		list_del_init(&vchan->node);
+		pchan_alloc |= BIT(pchan_idx);
+
+		/* Mark this channel allocated */
+		pchan->vchan = vchan;
+		vchan->phy = pchan;
+		dev_dbg(sdev->slave.dev, "pchan %u: alloc vchan %p\n",
+			pchan->idx, &vchan->vc);
+	}
+	spin_unlock_irq(&sdev->lock);
+
+	for (pchan_idx = 0; pchan_idx < NR_MAX_CHANNELS; pchan_idx++) {
+		if (!(pchan_alloc & BIT(pchan_idx)))
+			continue;
+
+		pchan = sdev->pchans + pchan_idx;
+		vchan = pchan->vchan;
+		if (vchan) {
+			spin_lock_irq(&vchan->vc.lock);
+			sun6i_dma_start_desc(vchan);
+			spin_unlock_irq(&vchan->vc.lock);
+		}
+	}
+}
+
+static irqreturn_t sun6i_dma_interrupt(int irq, void *dev_id)
+{
+	struct sun6i_dma_dev *sdev = dev_id;
+	struct sun6i_vchan *vchan;
+	struct sun6i_pchan *pchan;
+	int i, j, ret = IRQ_NONE;
+	u32 status;
+
+	for (i = 0; i < 2; i++) {
+		status = readl(sdev->base + DMA_IRQ_STAT(i));
+		if (!status)
+			continue;
+
+		dev_dbg(sdev->slave.dev, "DMA irq status %s: 0x%x\n",
+			i ? "high" : "low", status);
+
+		writel(status, sdev->base + DMA_IRQ_STAT(i));
+
+		for (j = 0; (j < 8) && status; j++) {
+			if (status & DMA_IRQ_QUEUE) {
+				pchan = sdev->pchans + j;
+				vchan = pchan->vchan;
+
+				if (vchan) {
+					spin_lock(&vchan->vc.lock);
+					vchan_cookie_complete(&pchan->desc->vd);
+					pchan->done = pchan->desc;
+					spin_unlock(&vchan->vc.lock);
+				}
+			}
+
+			status = status >> 4;
+		}
+
+		if (!atomic_read(&sdev->tasklet_shutdown))
+			tasklet_schedule(&sdev->task);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static struct dma_async_tx_descriptor *sun6i_dma_prep_dma_memcpy(
+		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+		size_t len, unsigned long flags)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct sun6i_dma_lli *v_lli;
+	struct sun6i_desc *txd;
+	dma_addr_t p_lli;
+	int ret;
+
+	dev_dbg(chan2dev(chan),
+		"%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
+		__func__, vchan->vc.chan.chan_id, &dest, &src, len, flags);
+
+	if (!len)
+		return NULL;
+
+	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
+	if (!txd)
+		return NULL;
+
+	v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
+	if (!v_lli) {
+		dev_err(sdev->slave.dev, "Failed to alloc lli memory\n");
+		kfree(txd);
+		return NULL;
+	}
+
+	ret = sun6i_dma_cfg_lli(v_lli, src, dest, len, sconfig);
+	if (ret)
+		goto err_dma_free;
+
+	v_lli->cfg |= DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
+		DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
+		DMA_CHAN_CFG_DST_LINEAR_MODE |
+		DMA_CHAN_CFG_SRC_LINEAR_MODE;
+
+	sun6i_dma_lli_add(NULL, v_lli, p_lli, txd);
+
+	sun6i_dma_dump_lli(vchan, v_lli);
+
+	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
+
+err_dma_free:
+	dma_pool_free(sdev->pool, v_lli, p_lli);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *sun6i_dma_prep_slave_sg(
+		struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction dir,
+		unsigned long flags, void *context)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct sun6i_dma_lli *v_lli, *prev = NULL;
+	struct sun6i_desc *txd;
+	struct scatterlist *sg;
+	dma_addr_t p_lli;
+	int i, ret;
+
+	if (!sgl)
+		return NULL;
+
+	if (!is_slave_direction(dir)) {
+		dev_err(chan2dev(chan), "Invalid DMA direction\n");
+		return NULL;
+	}
+
+	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
+	if (!txd)
+		return NULL;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
+		if (!v_lli) {
+			kfree(txd);
+			return NULL;
+		}
+
+		if (dir == DMA_MEM_TO_DEV) {
+			ret = sun6i_dma_cfg_lli(v_lli, sg_dma_address(sg),
+						sconfig->dst_addr, sg_dma_len(sg),
+						sconfig);
+			if (ret)
+				goto err_dma_free;
+
+			v_lli->cfg |= DMA_CHAN_CFG_DST_IO_MODE |
+				DMA_CHAN_CFG_SRC_LINEAR_MODE |
+				DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
+				DMA_CHAN_CFG_DST_DRQ(vchan->port);
+
+			dev_dbg(chan2dev(chan),
+				"%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
+				__func__, vchan->vc.chan.chan_id,
+				&sconfig->dst_addr, &sg_dma_address(sg),
+				sg_dma_len(sg), flags);
+
+		} else {
+			ret = sun6i_dma_cfg_lli(v_lli, sconfig->src_addr,
+						sg_dma_address(sg), sg_dma_len(sg),
+						sconfig);
+			if (ret)
+				goto err_dma_free;
+
+			v_lli->cfg |= DMA_CHAN_CFG_DST_LINEAR_MODE |
+				DMA_CHAN_CFG_SRC_IO_MODE |
+				DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
+				DMA_CHAN_CFG_SRC_DRQ(vchan->port);
+
+			dev_dbg(chan2dev(chan),
+				"%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
+				__func__, vchan->vc.chan.chan_id,
+				&sg_dma_address(sg), &sconfig->src_addr,
+				sg_dma_len(sg), flags);
+		}
+
+		prev = sun6i_dma_lli_add(prev, v_lli, p_lli, txd);
+	}
+
+	dev_dbg(chan2dev(chan), "First: %pad\n", &txd->p_lli);
+	for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
+		sun6i_dma_dump_lli(vchan, prev);
+
+	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
+
+err_dma_free:
+	dma_pool_free(sdev->pool, v_lli, p_lli);
+	return NULL;
+}
+
+static int sun6i_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+		       unsigned long arg)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct sun6i_pchan *pchan = vchan->phy;
+	unsigned long flags;
+	int ret = 0;
+
+	switch (cmd) {
+	case DMA_RESUME:
+		dev_dbg(chan2dev(chan), "vchan %p: resume\n", &vchan->vc);
+
+		spin_lock_irqsave(&vchan->vc.lock, flags);
+
+		if (pchan) {
+			writel(DMA_CHAN_PAUSE_RESUME,
+			       pchan->base + DMA_CHAN_PAUSE);
+		} else if (!list_empty(&vchan->vc.desc_issued)) {
+			spin_lock(&sdev->lock);
+			list_add_tail(&vchan->node, &sdev->pending);
+			spin_unlock(&sdev->lock);
+		}
+
+		spin_unlock_irqrestore(&vchan->vc.lock, flags);
+		break;
+
+	case DMA_PAUSE:
+		dev_dbg(chan2dev(chan), "vchan %p: pause\n", &vchan->vc);
+
+		if (pchan) {
+			writel(DMA_CHAN_PAUSE_PAUSE,
+			       pchan->base + DMA_CHAN_PAUSE);
+		} else {
+			spin_lock(&sdev->lock);
+			list_del_init(&vchan->node);
+			spin_unlock(&sdev->lock);
+		}
+		break;
+
+	case DMA_TERMINATE_ALL:
+		ret = sun6i_dma_terminate_all(vchan);
+		break;
+	case DMA_SLAVE_CONFIG:
+		memcpy(&vchan->cfg, (void *)arg, sizeof(struct dma_slave_config));
+		break;
+	default:
+		ret = -ENXIO;
+		break;
+	}
+	return ret;
+}
+
+static enum dma_status sun6i_dma_tx_status(struct dma_chan *chan,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *state)
+{
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct sun6i_pchan *pchan = vchan->phy;
+	struct sun6i_dma_lli *lli;
+	struct virt_dma_desc *vd;
+	struct sun6i_desc *txd;
+	enum dma_status ret;
+	unsigned long flags;
+	size_t bytes = 0;
+
+	ret = dma_cookie_status(chan, cookie, state);
+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	vd = vchan_find_desc(&vchan->vc, cookie);
+	txd = to_sun6i_desc(&vd->tx);
+
+	if (vd) {
+		for (lli = txd->v_lli; lli != NULL; lli = lli->v_lli_next)
+			bytes += lli->len;
+	} else if (!pchan || !pchan->desc) {
+		bytes = 0;
+	} else {
+		bytes = readl(pchan->base + DMA_CHAN_CUR_CNT);
+	}
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	dma_set_residue(state, bytes);
+
+	return ret;
+}
+
+static void sun6i_dma_issue_pending(struct dma_chan *chan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	if (vchan_issue_pending(&vchan->vc)) {
+		spin_lock(&sdev->lock);
+
+		if (!vchan->phy && list_empty(&vchan->node)) {
+			list_add_tail(&vchan->node, &sdev->pending);
+			tasklet_schedule(&sdev->task);
+			dev_dbg(chan2dev(chan), "vchan %p: issued\n",
+				&vchan->vc);
+		}
+
+		spin_unlock(&sdev->lock);
+	} else {
+		dev_dbg(chan2dev(chan), "vchan %p: nothing to issue\n",
+			&vchan->vc);
+	}
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+}
+
+static int sun6i_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+	return 0;
+}
+
+static void sun6i_dma_free_chan_resources(struct dma_chan *chan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&sdev->lock, flags);
+	list_del_init(&vchan->node);
+	spin_unlock_irqrestore(&sdev->lock, flags);
+
+	vchan_free_chan_resources(&vchan->vc);
+}
+
+static struct dma_chan *sun6i_dma_of_xlate(struct of_phandle_args *dma_spec,
+					   struct of_dma *ofdma)
+{
+	struct sun6i_dma_dev *sdev = ofdma->of_dma_data;
+	struct sun6i_vchan *vchan;
+	struct dma_chan *chan;
+	u8 port = dma_spec->args[0];
+
+	if (port > NR_MAX_REQUESTS)
+		return NULL;
+
+	chan = dma_get_any_slave_channel(&sdev->slave);
+	if (!chan)
+		return NULL;
+
+	vchan = to_sun6i_vchan(chan);
+	vchan->port = port;
+
+	return chan;
+}
+
+static inline void sun6i_kill_tasklet(struct sun6i_dma_dev *sdev)
+{
+	/* Disable all interrupts from DMA */
+	writel(0, sdev->base + DMA_IRQ_EN(0));
+	writel(0, sdev->base + DMA_IRQ_EN(1));
+
+	/* Prevent spurious interrupts from scheduling the tasklet */
+	atomic_inc(&sdev->tasklet_shutdown);
+
+	/* Make sure all interrupts are handled */
+	synchronize_irq(sdev->irq);
+
+	/* Actually prevent the tasklet from being scheduled */
+	tasklet_kill(&sdev->task);
+}
+
+static inline void sun6i_dma_free(struct sun6i_dma_dev *sdev)
+{
+	int i;
+
+	for (i = 0; i < NR_MAX_VCHANS; i++) {
+		struct sun6i_vchan *vchan = &sdev->vchans[i];
+
+		list_del(&vchan->vc.chan.device_node);
+		tasklet_kill(&vchan->vc.task);
+	}
+}
+
+static int sun6i_dma_probe(struct platform_device *pdev)
+{
+	struct sun6i_dma_dev *sdc;
+	struct resource *res;
+	struct clk *mux, *pll6;
+	int ret, i;
+
+	sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
+	if (!sdc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sdc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sdc->base))
+		return PTR_ERR(sdc->base);
+
+	sdc->irq = platform_get_irq(pdev, 0);
+	if (sdc->irq < 0) {
+		dev_err(&pdev->dev, "Cannot claim IRQ\n");
+		return sdc->irq;
+	}
+
+	sdc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(sdc->clk)) {
+		dev_err(&pdev->dev, "No clock specified\n");
+		return PTR_ERR(sdc->clk);
+	}
+
+	mux = clk_get(NULL, "ahb1_mux");
+	if (IS_ERR(mux)) {
+		dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
+		return PTR_ERR(mux);
+	}
+
+	pll6 = clk_get(NULL, "pll6");
+	if (IS_ERR(pll6)) {
+		dev_err(&pdev->dev, "Couldn't get PLL6\n");
+		clk_put(mux);
+		return PTR_ERR(pll6);
+	}
+
+	ret = clk_set_parent(mux, pll6);
+	clk_put(pll6);
+	clk_put(mux);
+
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
+		return ret;
+	}
+
+	sdc->rstc = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(sdc->rstc)) {
+		dev_err(&pdev->dev, "No reset controller specified\n");
+		return PTR_ERR(sdc->rstc);
+	}
+
+	sdc->pool = dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
+				     sizeof(struct sun6i_dma_lli), 4, 0);
+	if (!sdc->pool) {
+		dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, sdc);
+	INIT_LIST_HEAD(&sdc->pending);
+	spin_lock_init(&sdc->lock);
+
+	dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
+	dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
+	dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
+
+	INIT_LIST_HEAD(&sdc->slave.channels);
+	sdc->slave.device_alloc_chan_resources	= sun6i_dma_alloc_chan_resources;
+	sdc->slave.device_free_chan_resources	= sun6i_dma_free_chan_resources;
+	sdc->slave.device_tx_status		= sun6i_dma_tx_status;
+	sdc->slave.device_issue_pending		= sun6i_dma_issue_pending;
+	sdc->slave.device_prep_slave_sg		= sun6i_dma_prep_slave_sg;
+	sdc->slave.device_prep_dma_memcpy	= sun6i_dma_prep_dma_memcpy;
+	sdc->slave.device_control		= sun6i_dma_control;
+	sdc->slave.chancnt			= NR_MAX_VCHANS;
+
+	sdc->slave.dev = &pdev->dev;
+
+	sdc->pchans = devm_kcalloc(&pdev->dev, NR_MAX_CHANNELS,
+				   sizeof(struct sun6i_pchan), GFP_KERNEL);
+	if (!sdc->pchans)
+		return -ENOMEM;
+
+	sdc->vchans = devm_kcalloc(&pdev->dev, NR_MAX_VCHANS,
+				   sizeof(struct sun6i_vchan), GFP_KERNEL);
+	if (!sdc->vchans)
+		return -ENOMEM;
+
+	tasklet_init(&sdc->task, sun6i_dma_tasklet, (unsigned long)sdc);
+
+	for (i = 0; i < NR_MAX_CHANNELS; i++) {
+		struct sun6i_pchan *pchan = &sdc->pchans[i];
+
+		pchan->idx = i;
+		pchan->base = sdc->base + 0x100 + i * 0x40;
+	}
+
+	for (i = 0; i < NR_MAX_VCHANS; i++) {
+		struct sun6i_vchan *vchan = &sdc->vchans[i];
+
+		INIT_LIST_HEAD(&vchan->node);
+		vchan->vc.desc_free = sun6i_dma_free_desc;
+		vchan_init(&vchan->vc, &sdc->slave);
+	}
+
+	ret = reset_control_deassert(sdc->rstc);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't deassert the device from reset\n");
+		goto err_chan_free;
+	}
+
+	ret = clk_prepare_enable(sdc->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't enable the clock\n");
+		goto err_reset_assert;
+	}
+
+	ret = devm_request_irq(&pdev->dev, sdc->irq, sun6i_dma_interrupt, 0,
+			       dev_name(&pdev->dev), sdc);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot request IRQ\n");
+		goto err_clk_disable;
+	}
+
+	ret = dma_async_device_register(&sdc->slave);
+	if (ret) {
+		dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
+		goto err_irq_disable;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node, sun6i_dma_of_xlate,
+					 sdc);
+	if (ret) {
+		dev_err(&pdev->dev, "of_dma_controller_register failed\n");
+		goto err_dma_unregister;
+	}
+
+	return 0;
+
+err_dma_unregister:
+	dma_async_device_unregister(&sdc->slave);
+err_irq_disable:
+	sun6i_kill_tasklet(sdc);
+err_clk_disable:
+	clk_disable_unprepare(sdc->clk);
+err_reset_assert:
+	reset_control_assert(sdc->rstc);
+err_chan_free:
+	sun6i_dma_free(sdc);
+	return ret;
+}
+
+static int sun6i_dma_remove(struct platform_device *pdev)
+{
+	struct sun6i_dma_dev *sdc = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&sdc->slave);
+
+	sun6i_kill_tasklet(sdc);
+
+	clk_disable_unprepare(sdc->clk);
+	reset_control_assert(sdc->rstc);
+
+	sun6i_dma_free(sdc);
+
+	return 0;
+}
+
+static struct of_device_id sun6i_dma_match[] = {
+	{ .compatible = "allwinner,sun6i-a31-dma" }
+};
+
+static struct platform_driver sun6i_dma_driver = {
+	.probe		= sun6i_dma_probe,
+	.remove		= sun6i_dma_remove,
+	.driver = {
+		.name		= "sun6i-dma",
+		.of_match_table	= sun6i_dma_match,
+	},
+};
+module_platform_driver(sun6i_dma_driver);
+
+MODULE_DESCRIPTION("Allwinner A31 DMA Controller Driver");
+MODULE_AUTHOR("Sugar <shuge@allwinnertech.com>");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_LICENSE("GPL");
-- 
2.0.0

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

The Allwinner A31 has a 16 channels DMA controller that it shares with the
newer A23. Although sharing some similarities with the DMA controller of the
older Allwinner SoCs, it's significantly different, I don't expect it to be
possible to share the driver for these two.

The A31 Controller is able to memory-to-memory or memory-to-device transfers on
the 16 channels in parallel.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/dma/Kconfig     |    8 +
 drivers/dma/Makefile    |    1 +
 drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1067 insertions(+)
 create mode 100644 drivers/dma/sun6i-dma.c

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 1eca7b9760e6..4b439270fb11 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -375,6 +375,14 @@ config XILINX_VDMA
 	  channels, Memory Mapped to Stream (MM2S) and Stream to
 	  Memory Mapped (S2MM) for the data transfers.
 
+config DMA_SUN6I
+	tristate "Allwinner A31 SoCs DMA support"
+	depends on MACH_SUN6I || COMPILE_TEST
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Support for the DMA engine for Allwinner A31 SoCs.
+
 config DMA_ENGINE
 	bool
 
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index c779e1eb2db2..6807c50214c6 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -47,3 +47,4 @@ obj-$(CONFIG_MOXART_DMA) += moxart-dma.o
 obj-$(CONFIG_FSL_EDMA) += fsl-edma.o
 obj-$(CONFIG_QCOM_BAM_DMA) += qcom_bam_dma.o
 obj-y += xilinx/
+obj-$(CONFIG_DMA_SUN6I) += sun6i-dma.o
diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c
new file mode 100644
index 000000000000..8e82694f6dc4
--- /dev/null
+++ b/drivers/dma/sun6i-dma.c
@@ -0,0 +1,1058 @@
+/*
+ * Copyright (C) 2013-2014 Allwinner Tech Co., Ltd
+ * Author: Sugar <shuge@allwinnertech.com>
+ *
+ * Copyright (C) 2014 Maxime Ripard
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dmapool.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "virt-dma.h"
+
+/*
+ * There's 16 physical channels that can work in parallel.
+ *
+ * However we have 30 different endpoints for our requests.
+ *
+ * Since the channels are able to handle only an unidirectional
+ * transfer, we need to allocate more virtual channels so that
+ * everyone can grab one channel.
+ *
+ * Some devices can't work in both direction (mostly because it
+ * wouldn't make sense), so we have a bit fewer virtual channels than
+ * 2 channels per endpoints.
+ */
+
+#define NR_MAX_CHANNELS		16
+#define NR_MAX_REQUESTS		30
+#define NR_MAX_VCHANS		53
+
+/*
+ * Common registers
+ */
+#define DMA_IRQ_EN(x)		((x) * 0x04)
+#define DMA_IRQ_HALF			BIT(0)
+#define DMA_IRQ_PKG			BIT(1)
+#define DMA_IRQ_QUEUE			BIT(2)
+
+#define DMA_IRQ_CHAN_NR			8
+#define DMA_IRQ_CHAN_WIDTH		4
+
+
+#define DMA_IRQ_STAT(x)		((x) * 0x04 + 0x10)
+
+#define DMA_STAT		0x30
+
+/*
+ * Channels specific registers
+ */
+#define DMA_CHAN_ENABLE		0x00
+#define DMA_CHAN_ENABLE_START		BIT(0)
+#define DMA_CHAN_ENABLE_STOP		0
+
+#define DMA_CHAN_PAUSE		0x04
+#define DMA_CHAN_PAUSE_PAUSE		BIT(1)
+#define DMA_CHAN_PAUSE_RESUME		0
+
+#define DMA_CHAN_LLI_ADDR	0x08
+
+#define DMA_CHAN_CUR_CFG	0x0c
+#define DMA_CHAN_CFG_SRC_DRQ(x)		((x) & 0x1f)
+#define DMA_CHAN_CFG_SRC_IO_MODE	BIT(5)
+#define DMA_CHAN_CFG_SRC_LINEAR_MODE	(0 << 5)
+#define DMA_CHAN_CFG_SRC_BURST(x)	(((x) & 0x3) << 7)
+#define DMA_CHAN_CFG_SRC_WIDTH(x)	(((x) & 0x3) << 9)
+
+#define DMA_CHAN_CFG_DST_DRQ(x)		(DMA_CHAN_CFG_SRC_DRQ(x) << 16)
+#define DMA_CHAN_CFG_DST_IO_MODE	(DMA_CHAN_CFG_SRC_IO_MODE << 16)
+#define DMA_CHAN_CFG_DST_LINEAR_MODE	(DMA_CHAN_CFG_SRC_LINEAR_MODE << 16)
+#define DMA_CHAN_CFG_DST_BURST(x)	(DMA_CHAN_CFG_SRC_BURST(x) << 16)
+#define DMA_CHAN_CFG_DST_WIDTH(x)	(DMA_CHAN_CFG_SRC_WIDTH(x) << 16)
+
+#define DMA_CHAN_CUR_SRC	0x10
+
+#define DMA_CHAN_CUR_DST	0x14
+
+#define DMA_CHAN_CUR_CNT	0x18
+
+#define DMA_CHAN_CUR_PARA	0x1c
+
+
+/*
+ * Various hardware related defines
+ */
+#define LLI_LAST_ITEM	0xfffff800
+#define NORMAL_WAIT	8
+#define DRQ_SDRAM	1
+
+/*
+ * Hardware representation of the LLI
+ *
+ * The hardware will be fed the physical address of this structure,
+ * and read its content in order to start the transfer.
+ */
+struct sun6i_dma_lli {
+	u32			cfg;
+	u32			src;
+	u32			dst;
+	u32			len;
+	u32			para;
+	u32			p_lli_next;
+
+	/*
+	 * This field is not used by the DMA controller, but will be
+	 * used by the CPU to go through the list (mostly for dumping
+	 * or freeing it).
+	 */
+	struct sun6i_dma_lli	*v_lli_next;
+};
+
+
+struct sun6i_desc {
+	struct virt_dma_desc	vd;
+	dma_addr_t		p_lli;
+	struct sun6i_dma_lli	*v_lli;
+};
+
+struct sun6i_pchan {
+	u32			idx;
+	void __iomem		*base;
+	struct sun6i_vchan	*vchan;
+	struct sun6i_desc	*desc;
+	struct sun6i_desc	*done;
+};
+
+struct sun6i_vchan {
+	struct virt_dma_chan	vc;
+	struct list_head	node;
+	struct dma_slave_config	cfg;
+	struct sun6i_pchan	*phy;
+	u8			port;
+};
+
+struct sun6i_dma_dev {
+	struct dma_device	slave;
+	void __iomem		*base;
+	struct clk		*clk;
+	int			irq;
+	spinlock_t		lock;
+	struct reset_control	*rstc;
+	struct tasklet_struct	task;
+	atomic_t		tasklet_shutdown;
+	struct list_head	pending;
+	struct dma_pool		*pool;
+	struct sun6i_pchan	*pchans;
+	struct sun6i_vchan	*vchans;
+};
+
+static struct device *chan2dev(struct dma_chan *chan)
+{
+	return &chan->dev->device;
+}
+
+static inline struct sun6i_dma_dev *to_sun6i_dma_dev(struct dma_device *d)
+{
+	return container_of(d, struct sun6i_dma_dev, slave);
+}
+
+static inline struct sun6i_vchan *to_sun6i_vchan(struct dma_chan *chan)
+{
+	return container_of(chan, struct sun6i_vchan, vc.chan);
+}
+
+static inline struct sun6i_desc *
+to_sun6i_desc(struct dma_async_tx_descriptor *tx)
+{
+	return container_of(tx, struct sun6i_desc, vd.tx);
+}
+
+static inline void sun6i_dma_dump_com_regs(struct sun6i_dma_dev *sdev)
+{
+	dev_dbg(sdev->slave.dev, "Common register:\n"
+		"\tmask0(%04x): 0x%08x\n"
+		"\tmask1(%04x): 0x%08x\n"
+		"\tpend0(%04x): 0x%08x\n"
+		"\tpend1(%04x): 0x%08x\n"
+		"\tstats(%04x): 0x%08x\n",
+		DMA_IRQ_EN(0), readl(sdev->base + DMA_IRQ_EN(0)),
+		DMA_IRQ_EN(1), readl(sdev->base + DMA_IRQ_EN(1)),
+		DMA_IRQ_STAT(0), readl(sdev->base + DMA_IRQ_STAT(0)),
+		DMA_IRQ_STAT(1), readl(sdev->base + DMA_IRQ_STAT(1)),
+		DMA_STAT, readl(sdev->base + DMA_STAT));
+}
+
+static inline void sun6i_dma_dump_chan_regs(struct sun6i_dma_dev *sdev,
+					    struct sun6i_pchan *pchan)
+{
+	phys_addr_t reg = __virt_to_phys((unsigned long)pchan->base);
+
+	dev_dbg(sdev->slave.dev, "Chan %d reg: %pa\n"
+		"\t___en(%04x): \t0x%08x\n"
+		"\tpause(%04x): \t0x%08x\n"
+		"\tstart(%04x): \t0x%08x\n"
+		"\t__cfg(%04x): \t0x%08x\n"
+		"\t__src(%04x): \t0x%08x\n"
+		"\t__dst(%04x): \t0x%08x\n"
+		"\tcount(%04x): \t0x%08x\n"
+		"\t_para(%04x): \t0x%08x\n\n",
+		pchan->idx, &reg,
+		DMA_CHAN_ENABLE,
+		readl(pchan->base + DMA_CHAN_ENABLE),
+		DMA_CHAN_PAUSE,
+		readl(pchan->base + DMA_CHAN_PAUSE),
+		DMA_CHAN_LLI_ADDR,
+		readl(pchan->base + DMA_CHAN_LLI_ADDR),
+		DMA_CHAN_CUR_CFG,
+		readl(pchan->base + DMA_CHAN_CUR_CFG),
+		DMA_CHAN_CUR_SRC,
+		readl(pchan->base + DMA_CHAN_CUR_SRC),
+		DMA_CHAN_CUR_DST,
+		readl(pchan->base + DMA_CHAN_CUR_DST),
+		DMA_CHAN_CUR_CNT,
+		readl(pchan->base + DMA_CHAN_CUR_CNT),
+		DMA_CHAN_CUR_PARA,
+		readl(pchan->base + DMA_CHAN_CUR_PARA));
+}
+
+static inline int convert_burst(u32 maxburst, u8 *burst)
+{
+	switch (maxburst) {
+	case 1:
+		*burst = 0;
+		break;
+	case 8:
+		*burst = 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline int convert_buswidth(enum dma_slave_buswidth addr_width, u8 *width)
+{
+	switch (addr_width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		*width = 0;
+		break;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		*width = 1;
+		break;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		*width = 2;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void *sun6i_dma_lli_add(struct sun6i_dma_lli *prev,
+			       struct sun6i_dma_lli *next,
+			       dma_addr_t next_phy,
+			       struct sun6i_desc *txd)
+{
+	if ((!prev && !txd) || !next)
+		return NULL;
+
+	if (!prev) {
+		txd->p_lli = next_phy;
+		txd->v_lli = next;
+	} else {
+		prev->p_lli_next = next_phy;
+		prev->v_lli_next = next;
+	}
+
+	next->p_lli_next = LLI_LAST_ITEM;
+	next->v_lli_next = NULL;
+
+	return next;
+}
+
+static inline int sun6i_dma_cfg_lli(struct sun6i_dma_lli *lli,
+				    dma_addr_t src,
+				    dma_addr_t dst, u32 len,
+				    struct dma_slave_config *config)
+{
+	u8 src_width, dst_width, src_burst, dst_burst;
+	int ret;
+
+	if (!config)
+		return -EINVAL;
+
+	ret = convert_burst(config->src_maxburst, &src_burst);
+	if (ret)
+		return ret;
+
+	ret = convert_burst(config->dst_maxburst, &dst_burst);
+	if (ret)
+		return ret;
+
+	ret = convert_buswidth(config->src_addr_width, &src_width);
+	if (ret)
+		return ret;
+
+	ret = convert_buswidth(config->dst_addr_width, &dst_width);
+	if (ret)
+		return ret;
+
+	lli->cfg = DMA_CHAN_CFG_SRC_BURST(src_burst) |
+		DMA_CHAN_CFG_SRC_WIDTH(src_width) |
+		DMA_CHAN_CFG_DST_BURST(dst_burst) |
+		DMA_CHAN_CFG_DST_WIDTH(dst_width);
+
+	lli->src = src;
+	lli->dst = dst;
+	lli->len = len;
+	lli->para = NORMAL_WAIT;
+
+	return 0;
+}
+
+static inline void sun6i_dma_dump_lli(struct sun6i_vchan *vchan,
+				      struct sun6i_dma_lli *lli)
+{
+	phys_addr_t p_lli = __virt_to_phys((unsigned long)lli);
+
+	dev_dbg(chan2dev(&vchan->vc.chan),
+		"\n\tdesc:   p - %pa v - 0x%p\n"
+		"\t\tc - 0x%08x s - 0x%08x d - 0x%08x\n"
+		"\t\tl - 0x%08x p - 0x%08x n - 0x%08x\n",
+		&p_lli, lli,
+		lli->cfg, lli->src, lli->dst,
+		lli->len, lli->para, lli->p_lli_next);
+}
+
+static void sun6i_dma_free_desc(struct virt_dma_desc *vd)
+{
+	struct sun6i_desc *txd = to_sun6i_desc(&vd->tx);
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vd->tx.chan->device);
+	struct sun6i_dma_lli *v_lli, *v_next;
+	dma_addr_t p_lli, p_next;
+
+	if (unlikely(!txd))
+		return;
+
+	p_lli = txd->p_lli;
+	v_lli = txd->v_lli;
+
+	while (v_lli) {
+		v_next = v_lli->v_lli_next;
+		p_next = v_lli->p_lli_next;
+
+		dma_pool_free(sdev->pool, v_lli, p_lli);
+
+		v_lli = v_next;
+		p_lli = p_next;
+	}
+
+	kfree(txd);
+}
+
+static int sun6i_dma_terminate_all(struct sun6i_vchan *vchan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vchan->vc.chan.device);
+	struct sun6i_pchan *pchan = vchan->phy;
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock(&sdev->lock);
+	list_del_init(&vchan->node);
+	spin_unlock(&sdev->lock);
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	vchan_get_all_descriptors(&vchan->vc, &head);
+
+	if (pchan) {
+		writel(DMA_CHAN_ENABLE_STOP, pchan->base + DMA_CHAN_ENABLE);
+		writel(DMA_CHAN_PAUSE_RESUME, pchan->base + DMA_CHAN_PAUSE);
+
+		vchan->phy = NULL;
+		pchan->vchan = NULL;
+		pchan->desc = NULL;
+		pchan->done = NULL;
+	}
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	vchan_dma_desc_free_list(&vchan->vc, &head);
+
+	return 0;
+}
+
+static int sun6i_dma_start_desc(struct sun6i_vchan *vchan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(vchan->vc.chan.device);
+	struct virt_dma_desc *desc = vchan_next_desc(&vchan->vc);
+	struct sun6i_pchan *pchan = vchan->phy;
+	u32 irq_val, irq_reg, irq_offset;
+
+	if (!pchan)
+		return -EAGAIN;
+
+	if (!desc) {
+		pchan->desc = NULL;
+		pchan->done = NULL;
+		return -EAGAIN;
+	}
+
+	list_del(&desc->node);
+
+	pchan->desc = to_sun6i_desc(&desc->tx);
+	pchan->done = NULL;
+
+	sun6i_dma_dump_lli(vchan, pchan->desc->v_lli);
+
+	irq_reg = pchan->idx / DMA_IRQ_CHAN_NR;
+	irq_offset = pchan->idx % DMA_IRQ_CHAN_NR;
+
+	irq_val = readl(sdev->base + DMA_IRQ_EN(irq_offset));
+	irq_val |= DMA_IRQ_QUEUE << (irq_offset * DMA_IRQ_CHAN_WIDTH);
+	writel(irq_val, sdev->base + DMA_IRQ_EN(irq_offset));
+
+	writel(pchan->desc->p_lli, pchan->base + DMA_CHAN_LLI_ADDR);
+	writel(DMA_CHAN_ENABLE_START, pchan->base + DMA_CHAN_ENABLE);
+
+	sun6i_dma_dump_com_regs(sdev);
+	sun6i_dma_dump_chan_regs(sdev, pchan);
+
+	return 0;
+}
+
+static void sun6i_dma_tasklet(unsigned long data)
+{
+	struct sun6i_dma_dev *sdev = (struct sun6i_dma_dev *)data;
+	struct sun6i_vchan *vchan;
+	struct sun6i_pchan *pchan;
+	unsigned int pchan_alloc = 0;
+	unsigned int pchan_idx;
+
+	list_for_each_entry(vchan, &sdev->slave.channels, vc.chan.device_node) {
+		spin_lock_irq(&vchan->vc.lock);
+
+		pchan = vchan->phy;
+
+		if (pchan && pchan->done) {
+			if (sun6i_dma_start_desc(vchan)) {
+				/*
+				 * No current txd associated with this channel
+				 */
+				dev_dbg(sdev->slave.dev, "pchan %u: free\n",
+					pchan->idx);
+
+				/* Mark this channel free */
+				vchan->phy = NULL;
+				pchan->vchan = NULL;
+			}
+		}
+		spin_unlock_irq(&vchan->vc.lock);
+	}
+
+	spin_lock_irq(&sdev->lock);
+	for (pchan_idx = 0; pchan_idx < NR_MAX_CHANNELS; pchan_idx++) {
+		pchan = &sdev->pchans[pchan_idx];
+
+		if (pchan->vchan || list_empty(&sdev->pending))
+			continue;
+
+		vchan = list_first_entry(&sdev->pending,
+					 struct sun6i_vchan, node);
+
+		/* Remove from pending channels */
+		list_del_init(&vchan->node);
+		pchan_alloc |= BIT(pchan_idx);
+
+		/* Mark this channel allocated */
+		pchan->vchan = vchan;
+		vchan->phy = pchan;
+		dev_dbg(sdev->slave.dev, "pchan %u: alloc vchan %p\n",
+			pchan->idx, &vchan->vc);
+	}
+	spin_unlock_irq(&sdev->lock);
+
+	for (pchan_idx = 0; pchan_idx < NR_MAX_CHANNELS; pchan_idx++) {
+		if (!(pchan_alloc & BIT(pchan_idx)))
+			continue;
+
+		pchan = sdev->pchans + pchan_idx;
+		vchan = pchan->vchan;
+		if (vchan) {
+			spin_lock_irq(&vchan->vc.lock);
+			sun6i_dma_start_desc(vchan);
+			spin_unlock_irq(&vchan->vc.lock);
+		}
+	}
+}
+
+static irqreturn_t sun6i_dma_interrupt(int irq, void *dev_id)
+{
+	struct sun6i_dma_dev *sdev = dev_id;
+	struct sun6i_vchan *vchan;
+	struct sun6i_pchan *pchan;
+	int i, j, ret = IRQ_NONE;
+	u32 status;
+
+	for (i = 0; i < 2; i++) {
+		status = readl(sdev->base + DMA_IRQ_STAT(i));
+		if (!status)
+			continue;
+
+		dev_dbg(sdev->slave.dev, "DMA irq status %s: 0x%x\n",
+			i ? "high" : "low", status);
+
+		writel(status, sdev->base + DMA_IRQ_STAT(i));
+
+		for (j = 0; (j < 8) && status; j++) {
+			if (status & DMA_IRQ_QUEUE) {
+				pchan = sdev->pchans + j;
+				vchan = pchan->vchan;
+
+				if (vchan) {
+					spin_lock(&vchan->vc.lock);
+					vchan_cookie_complete(&pchan->desc->vd);
+					pchan->done = pchan->desc;
+					spin_unlock(&vchan->vc.lock);
+				}
+			}
+
+			status = status >> 4;
+		}
+
+		if (!atomic_read(&sdev->tasklet_shutdown))
+			tasklet_schedule(&sdev->task);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static struct dma_async_tx_descriptor *sun6i_dma_prep_dma_memcpy(
+		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+		size_t len, unsigned long flags)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct sun6i_dma_lli *v_lli;
+	struct sun6i_desc *txd;
+	dma_addr_t p_lli;
+	int ret;
+
+	dev_dbg(chan2dev(chan),
+		"%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
+		__func__, vchan->vc.chan.chan_id, &dest, &src, len, flags);
+
+	if (!len)
+		return NULL;
+
+	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
+	if (!txd)
+		return NULL;
+
+	v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
+	if (!v_lli) {
+		dev_err(sdev->slave.dev, "Failed to alloc lli memory\n");
+		kfree(txd);
+		return NULL;
+	}
+
+	ret = sun6i_dma_cfg_lli(v_lli, src, dest, len, sconfig);
+	if (ret)
+		goto err_dma_free;
+
+	v_lli->cfg |= DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
+		DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
+		DMA_CHAN_CFG_DST_LINEAR_MODE |
+		DMA_CHAN_CFG_SRC_LINEAR_MODE;
+
+	sun6i_dma_lli_add(NULL, v_lli, p_lli, txd);
+
+	sun6i_dma_dump_lli(vchan, v_lli);
+
+	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
+
+err_dma_free:
+	dma_pool_free(sdev->pool, v_lli, p_lli);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *sun6i_dma_prep_slave_sg(
+		struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction dir,
+		unsigned long flags, void *context)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct dma_slave_config *sconfig = &vchan->cfg;
+	struct sun6i_dma_lli *v_lli, *prev = NULL;
+	struct sun6i_desc *txd;
+	struct scatterlist *sg;
+	dma_addr_t p_lli;
+	int i, ret;
+
+	if (!sgl)
+		return NULL;
+
+	if (!is_slave_direction(dir)) {
+		dev_err(chan2dev(chan), "Invalid DMA direction\n");
+		return NULL;
+	}
+
+	txd = kzalloc(sizeof(*txd), GFP_NOWAIT);
+	if (!txd)
+		return NULL;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		v_lli = dma_pool_alloc(sdev->pool, GFP_NOWAIT, &p_lli);
+		if (!v_lli) {
+			kfree(txd);
+			return NULL;
+		}
+
+		if (dir == DMA_MEM_TO_DEV) {
+			ret = sun6i_dma_cfg_lli(v_lli, sg_dma_address(sg),
+						sconfig->dst_addr, sg_dma_len(sg),
+						sconfig);
+			if (ret)
+				goto err_dma_free;
+
+			v_lli->cfg |= DMA_CHAN_CFG_DST_IO_MODE |
+				DMA_CHAN_CFG_SRC_LINEAR_MODE |
+				DMA_CHAN_CFG_SRC_DRQ(DRQ_SDRAM) |
+				DMA_CHAN_CFG_DST_DRQ(vchan->port);
+
+			dev_dbg(chan2dev(chan),
+				"%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
+				__func__, vchan->vc.chan.chan_id,
+				&sconfig->dst_addr, &sg_dma_address(sg),
+				sg_dma_len(sg), flags);
+
+		} else {
+			ret = sun6i_dma_cfg_lli(v_lli, sconfig->src_addr,
+						sg_dma_address(sg), sg_dma_len(sg),
+						sconfig);
+			if (ret)
+				goto err_dma_free;
+
+			v_lli->cfg |= DMA_CHAN_CFG_DST_LINEAR_MODE |
+				DMA_CHAN_CFG_SRC_IO_MODE |
+				DMA_CHAN_CFG_DST_DRQ(DRQ_SDRAM) |
+				DMA_CHAN_CFG_SRC_DRQ(vchan->port);
+
+			dev_dbg(chan2dev(chan),
+				"%s; chan: %d, dest: %pad, src: %pad, len: %zu. flags: 0x%08lx\n",
+				__func__, vchan->vc.chan.chan_id,
+				&sg_dma_address(sg), &sconfig->src_addr,
+				sg_dma_len(sg), flags);
+		}
+
+		prev = sun6i_dma_lli_add(prev, v_lli, p_lli, txd);
+	}
+
+	dev_dbg(chan2dev(chan), "First: %pad\n", &txd->p_lli);
+	for (prev = txd->v_lli; prev; prev = prev->v_lli_next)
+		sun6i_dma_dump_lli(vchan, prev);
+
+	return vchan_tx_prep(&vchan->vc, &txd->vd, flags);
+
+err_dma_free:
+	dma_pool_free(sdev->pool, v_lli, p_lli);
+	return NULL;
+}
+
+static int sun6i_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+		       unsigned long arg)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct sun6i_pchan *pchan = vchan->phy;
+	unsigned long flags;
+	int ret = 0;
+
+	switch (cmd) {
+	case DMA_RESUME:
+		dev_dbg(chan2dev(chan), "vchan %p: resume\n", &vchan->vc);
+
+		spin_lock_irqsave(&vchan->vc.lock, flags);
+
+		if (pchan) {
+			writel(DMA_CHAN_PAUSE_RESUME,
+			       pchan->base + DMA_CHAN_PAUSE);
+		} else if (!list_empty(&vchan->vc.desc_issued)) {
+			spin_lock(&sdev->lock);
+			list_add_tail(&vchan->node, &sdev->pending);
+			spin_unlock(&sdev->lock);
+		}
+
+		spin_unlock_irqrestore(&vchan->vc.lock, flags);
+		break;
+
+	case DMA_PAUSE:
+		dev_dbg(chan2dev(chan), "vchan %p: pause\n", &vchan->vc);
+
+		if (pchan) {
+			writel(DMA_CHAN_PAUSE_PAUSE,
+			       pchan->base + DMA_CHAN_PAUSE);
+		} else {
+			spin_lock(&sdev->lock);
+			list_del_init(&vchan->node);
+			spin_unlock(&sdev->lock);
+		}
+		break;
+
+	case DMA_TERMINATE_ALL:
+		ret = sun6i_dma_terminate_all(vchan);
+		break;
+	case DMA_SLAVE_CONFIG:
+		memcpy(&vchan->cfg, (void *)arg, sizeof(struct dma_slave_config));
+		break;
+	default:
+		ret = -ENXIO;
+		break;
+	}
+	return ret;
+}
+
+static enum dma_status sun6i_dma_tx_status(struct dma_chan *chan,
+					   dma_cookie_t cookie,
+					   struct dma_tx_state *state)
+{
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	struct sun6i_pchan *pchan = vchan->phy;
+	struct sun6i_dma_lli *lli;
+	struct virt_dma_desc *vd;
+	struct sun6i_desc *txd;
+	enum dma_status ret;
+	unsigned long flags;
+	size_t bytes = 0;
+
+	ret = dma_cookie_status(chan, cookie, state);
+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	vd = vchan_find_desc(&vchan->vc, cookie);
+	txd = to_sun6i_desc(&vd->tx);
+
+	if (vd) {
+		for (lli = txd->v_lli; lli != NULL; lli = lli->v_lli_next)
+			bytes += lli->len;
+	} else if (!pchan || !pchan->desc) {
+		bytes = 0;
+	} else {
+		bytes = readl(pchan->base + DMA_CHAN_CUR_CNT);
+	}
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+
+	dma_set_residue(state, bytes);
+
+	return ret;
+}
+
+static void sun6i_dma_issue_pending(struct dma_chan *chan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&vchan->vc.lock, flags);
+
+	if (vchan_issue_pending(&vchan->vc)) {
+		spin_lock(&sdev->lock);
+
+		if (!vchan->phy && list_empty(&vchan->node)) {
+			list_add_tail(&vchan->node, &sdev->pending);
+			tasklet_schedule(&sdev->task);
+			dev_dbg(chan2dev(chan), "vchan %p: issued\n",
+				&vchan->vc);
+		}
+
+		spin_unlock(&sdev->lock);
+	} else {
+		dev_dbg(chan2dev(chan), "vchan %p: nothing to issue\n",
+			&vchan->vc);
+	}
+
+	spin_unlock_irqrestore(&vchan->vc.lock, flags);
+}
+
+static int sun6i_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+	return 0;
+}
+
+static void sun6i_dma_free_chan_resources(struct dma_chan *chan)
+{
+	struct sun6i_dma_dev *sdev = to_sun6i_dma_dev(chan->device);
+	struct sun6i_vchan *vchan = to_sun6i_vchan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&sdev->lock, flags);
+	list_del_init(&vchan->node);
+	spin_unlock_irqrestore(&sdev->lock, flags);
+
+	vchan_free_chan_resources(&vchan->vc);
+}
+
+static struct dma_chan *sun6i_dma_of_xlate(struct of_phandle_args *dma_spec,
+					   struct of_dma *ofdma)
+{
+	struct sun6i_dma_dev *sdev = ofdma->of_dma_data;
+	struct sun6i_vchan *vchan;
+	struct dma_chan *chan;
+	u8 port = dma_spec->args[0];
+
+	if (port > NR_MAX_REQUESTS)
+		return NULL;
+
+	chan = dma_get_any_slave_channel(&sdev->slave);
+	if (!chan)
+		return NULL;
+
+	vchan = to_sun6i_vchan(chan);
+	vchan->port = port;
+
+	return chan;
+}
+
+static inline void sun6i_kill_tasklet(struct sun6i_dma_dev *sdev)
+{
+	/* Disable all interrupts from DMA */
+	writel(0, sdev->base + DMA_IRQ_EN(0));
+	writel(0, sdev->base + DMA_IRQ_EN(1));
+
+	/* Prevent spurious interrupts from scheduling the tasklet */
+	atomic_inc(&sdev->tasklet_shutdown);
+
+	/* Make sure all interrupts are handled */
+	synchronize_irq(sdev->irq);
+
+	/* Actually prevent the tasklet from being scheduled */
+	tasklet_kill(&sdev->task);
+}
+
+static inline void sun6i_dma_free(struct sun6i_dma_dev *sdev)
+{
+	int i;
+
+	for (i = 0; i < NR_MAX_VCHANS; i++) {
+		struct sun6i_vchan *vchan = &sdev->vchans[i];
+
+		list_del(&vchan->vc.chan.device_node);
+		tasklet_kill(&vchan->vc.task);
+	}
+}
+
+static int sun6i_dma_probe(struct platform_device *pdev)
+{
+	struct sun6i_dma_dev *sdc;
+	struct resource *res;
+	struct clk *mux, *pll6;
+	int ret, i;
+
+	sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
+	if (!sdc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sdc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(sdc->base))
+		return PTR_ERR(sdc->base);
+
+	sdc->irq = platform_get_irq(pdev, 0);
+	if (sdc->irq < 0) {
+		dev_err(&pdev->dev, "Cannot claim IRQ\n");
+		return sdc->irq;
+	}
+
+	sdc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(sdc->clk)) {
+		dev_err(&pdev->dev, "No clock specified\n");
+		return PTR_ERR(sdc->clk);
+	}
+
+	mux = clk_get(NULL, "ahb1_mux");
+	if (IS_ERR(mux)) {
+		dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
+		return PTR_ERR(mux);
+	}
+
+	pll6 = clk_get(NULL, "pll6");
+	if (IS_ERR(pll6)) {
+		dev_err(&pdev->dev, "Couldn't get PLL6\n");
+		clk_put(mux);
+		return PTR_ERR(pll6);
+	}
+
+	ret = clk_set_parent(mux, pll6);
+	clk_put(pll6);
+	clk_put(mux);
+
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
+		return ret;
+	}
+
+	sdc->rstc = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(sdc->rstc)) {
+		dev_err(&pdev->dev, "No reset controller specified\n");
+		return PTR_ERR(sdc->rstc);
+	}
+
+	sdc->pool = dmam_pool_create(dev_name(&pdev->dev), &pdev->dev,
+				     sizeof(struct sun6i_dma_lli), 4, 0);
+	if (!sdc->pool) {
+		dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
+		return -ENOMEM;
+	}
+
+	platform_set_drvdata(pdev, sdc);
+	INIT_LIST_HEAD(&sdc->pending);
+	spin_lock_init(&sdc->lock);
+
+	dma_cap_set(DMA_PRIVATE, sdc->slave.cap_mask);
+	dma_cap_set(DMA_MEMCPY, sdc->slave.cap_mask);
+	dma_cap_set(DMA_SLAVE, sdc->slave.cap_mask);
+
+	INIT_LIST_HEAD(&sdc->slave.channels);
+	sdc->slave.device_alloc_chan_resources	= sun6i_dma_alloc_chan_resources;
+	sdc->slave.device_free_chan_resources	= sun6i_dma_free_chan_resources;
+	sdc->slave.device_tx_status		= sun6i_dma_tx_status;
+	sdc->slave.device_issue_pending		= sun6i_dma_issue_pending;
+	sdc->slave.device_prep_slave_sg		= sun6i_dma_prep_slave_sg;
+	sdc->slave.device_prep_dma_memcpy	= sun6i_dma_prep_dma_memcpy;
+	sdc->slave.device_control		= sun6i_dma_control;
+	sdc->slave.chancnt			= NR_MAX_VCHANS;
+
+	sdc->slave.dev = &pdev->dev;
+
+	sdc->pchans = devm_kcalloc(&pdev->dev, NR_MAX_CHANNELS,
+				   sizeof(struct sun6i_pchan), GFP_KERNEL);
+	if (!sdc->pchans)
+		return -ENOMEM;
+
+	sdc->vchans = devm_kcalloc(&pdev->dev, NR_MAX_VCHANS,
+				   sizeof(struct sun6i_vchan), GFP_KERNEL);
+	if (!sdc->vchans)
+		return -ENOMEM;
+
+	tasklet_init(&sdc->task, sun6i_dma_tasklet, (unsigned long)sdc);
+
+	for (i = 0; i < NR_MAX_CHANNELS; i++) {
+		struct sun6i_pchan *pchan = &sdc->pchans[i];
+
+		pchan->idx = i;
+		pchan->base = sdc->base + 0x100 + i * 0x40;
+	}
+
+	for (i = 0; i < NR_MAX_VCHANS; i++) {
+		struct sun6i_vchan *vchan = &sdc->vchans[i];
+
+		INIT_LIST_HEAD(&vchan->node);
+		vchan->vc.desc_free = sun6i_dma_free_desc;
+		vchan_init(&vchan->vc, &sdc->slave);
+	}
+
+	ret = reset_control_deassert(sdc->rstc);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't deassert the device from reset\n");
+		goto err_chan_free;
+	}
+
+	ret = clk_prepare_enable(sdc->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Couldn't enable the clock\n");
+		goto err_reset_assert;
+	}
+
+	ret = devm_request_irq(&pdev->dev, sdc->irq, sun6i_dma_interrupt, 0,
+			       dev_name(&pdev->dev), sdc);
+	if (ret) {
+		dev_err(&pdev->dev, "Cannot request IRQ\n");
+		goto err_clk_disable;
+	}
+
+	ret = dma_async_device_register(&sdc->slave);
+	if (ret) {
+		dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
+		goto err_irq_disable;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node, sun6i_dma_of_xlate,
+					 sdc);
+	if (ret) {
+		dev_err(&pdev->dev, "of_dma_controller_register failed\n");
+		goto err_dma_unregister;
+	}
+
+	return 0;
+
+err_dma_unregister:
+	dma_async_device_unregister(&sdc->slave);
+err_irq_disable:
+	sun6i_kill_tasklet(sdc);
+err_clk_disable:
+	clk_disable_unprepare(sdc->clk);
+err_reset_assert:
+	reset_control_assert(sdc->rstc);
+err_chan_free:
+	sun6i_dma_free(sdc);
+	return ret;
+}
+
+static int sun6i_dma_remove(struct platform_device *pdev)
+{
+	struct sun6i_dma_dev *sdc = platform_get_drvdata(pdev);
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&sdc->slave);
+
+	sun6i_kill_tasklet(sdc);
+
+	clk_disable_unprepare(sdc->clk);
+	reset_control_assert(sdc->rstc);
+
+	sun6i_dma_free(sdc);
+
+	return 0;
+}
+
+static struct of_device_id sun6i_dma_match[] = {
+	{ .compatible = "allwinner,sun6i-a31-dma" }
+};
+
+static struct platform_driver sun6i_dma_driver = {
+	.probe		= sun6i_dma_probe,
+	.remove		= sun6i_dma_remove,
+	.driver = {
+		.name		= "sun6i-dma",
+		.of_match_table	= sun6i_dma_match,
+	},
+};
+module_platform_driver(sun6i_dma_driver);
+
+MODULE_DESCRIPTION("Allwinner A31 DMA Controller Driver");
+MODULE_AUTHOR("Sugar <shuge@allwinnertech.com>");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_LICENSE("GPL");
-- 
2.0.0

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Rutland]

Hi Maxime,

On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> The Allwinner A31 has a 16 channels DMA controller that it shares with the
> newer A23. Although sharing some similarities with the DMA controller of the
> older Allwinner SoCs, it's significantly different, I don't expect it to be
> possible to share the driver for these two.
>
> The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> the 16 channels in parallel.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/dma/Kconfig     |    8 +
>  drivers/dma/Makefile    |    1 +
>  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1067 insertions(+)
>  create mode 100644 drivers/dma/sun6i-dma.c

[...]

> +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> +       if (IS_ERR(sdc->clk)) {
> +               dev_err(&pdev->dev, "No clock specified\n");
> +               return PTR_ERR(sdc->clk);
> +       }
> +
> +       mux = clk_get(NULL, "ahb1_mux");
> +       if (IS_ERR(mux)) {
> +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> +               return PTR_ERR(mux);
> +       }
> +
> +       pll6 = clk_get(NULL, "pll6");
> +       if (IS_ERR(pll6)) {
> +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> +               clk_put(mux);
> +               return PTR_ERR(pll6);
> +       }

I'm slightly confused. The binding listed a single unnamed clock (the
AHB clock). What is going on here?

> +       ret = clk_set_parent(mux, pll6);
> +       clk_put(pll6);
> +       clk_put(mux);
> +
> +       if (ret) {
> +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> +               return ret;
> +       }

Why do we need to reparent the mux?

Thanks,
Mark.

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Rutland]

Hi Maxime,

On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> The Allwinner A31 has a 16 channels DMA controller that it shares with the
> newer A23. Although sharing some similarities with the DMA controller of the
> older Allwinner SoCs, it's significantly different, I don't expect it to be
> possible to share the driver for these two.
>
> The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> the 16 channels in parallel.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/dma/Kconfig     |    8 +
>  drivers/dma/Makefile    |    1 +
>  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 1067 insertions(+)
>  create mode 100644 drivers/dma/sun6i-dma.c

[...]

> +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> +       if (IS_ERR(sdc->clk)) {
> +               dev_err(&pdev->dev, "No clock specified\n");
> +               return PTR_ERR(sdc->clk);
> +       }
> +
> +       mux = clk_get(NULL, "ahb1_mux");
> +       if (IS_ERR(mux)) {
> +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> +               return PTR_ERR(mux);
> +       }
> +
> +       pll6 = clk_get(NULL, "pll6");
> +       if (IS_ERR(pll6)) {
> +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> +               clk_put(mux);
> +               return PTR_ERR(pll6);
> +       }

I'm slightly confused. The binding listed a single unnamed clock (the
AHB clock). What is going on here?

> +       ret = clk_set_parent(mux, pll6);
> +       clk_put(pll6);
> +       clk_put(mux);
> +
> +       if (ret) {
> +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> +               return ret;
> +       }

Why do we need to reparent the mux?

Thanks,
Mark.

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 2304 bytes --]

On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> Hi Maxime,
> 
> On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > newer A23. Although sharing some similarities with the DMA controller of the
> > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > possible to share the driver for these two.
> >
> > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > the 16 channels in parallel.
> >
> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> >  drivers/dma/Kconfig     |    8 +
> >  drivers/dma/Makefile    |    1 +
> >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 1067 insertions(+)
> >  create mode 100644 drivers/dma/sun6i-dma.c
> 
> [...]
> 
> > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > +       if (IS_ERR(sdc->clk)) {
> > +               dev_err(&pdev->dev, "No clock specified\n");
> > +               return PTR_ERR(sdc->clk);
> > +       }
> > +
> > +       mux = clk_get(NULL, "ahb1_mux");
> > +       if (IS_ERR(mux)) {
> > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > +               return PTR_ERR(mux);
> > +       }
> > +
> > +       pll6 = clk_get(NULL, "pll6");
> > +       if (IS_ERR(pll6)) {
> > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > +               clk_put(mux);
> > +               return PTR_ERR(pll6);
> > +       }
> 
> I'm slightly confused. The binding listed a single unnamed clock (the
> AHB clock). What is going on here?

The device itself needs only a single clock to work...

> 
> > +       ret = clk_set_parent(mux, pll6);
> > +       clk_put(pll6);
> > +       clk_put(mux);
> > +
> > +       if (ret) {
> > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > +               return ret;
> > +       }
> 
> Why do we need to reparent the mux?

... but will function only if this clock is derived from PLL6.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> Hi Maxime,
> 
> On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > newer A23. Although sharing some similarities with the DMA controller of the
> > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > possible to share the driver for these two.
> >
> > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > the 16 channels in parallel.
> >
> > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> >  drivers/dma/Kconfig     |    8 +
> >  drivers/dma/Makefile    |    1 +
> >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 1067 insertions(+)
> >  create mode 100644 drivers/dma/sun6i-dma.c
> 
> [...]
> 
> > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > +       if (IS_ERR(sdc->clk)) {
> > +               dev_err(&pdev->dev, "No clock specified\n");
> > +               return PTR_ERR(sdc->clk);
> > +       }
> > +
> > +       mux = clk_get(NULL, "ahb1_mux");
> > +       if (IS_ERR(mux)) {
> > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > +               return PTR_ERR(mux);
> > +       }
> > +
> > +       pll6 = clk_get(NULL, "pll6");
> > +       if (IS_ERR(pll6)) {
> > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > +               clk_put(mux);
> > +               return PTR_ERR(pll6);
> > +       }
> 
> I'm slightly confused. The binding listed a single unnamed clock (the
> AHB clock). What is going on here?

The device itself needs only a single clock to work...

> 
> > +       ret = clk_set_parent(mux, pll6);
> > +       clk_put(pll6);
> > +       clk_put(mux);
> > +
> > +       if (ret) {
> > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > +               return ret;
> > +       }
> 
> Why do we need to reparent the mux?

... but will function only if this clock is derived from PLL6.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140630/5f27ba48/attachment.sig>

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Rutland]

On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > Hi Maxime,
> > 
> > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > newer A23. Although sharing some similarities with the DMA controller of the
> > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > possible to share the driver for these two.
> > >
> > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > the 16 channels in parallel.
> > >
> > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > ---
> > >  drivers/dma/Kconfig     |    8 +
> > >  drivers/dma/Makefile    |    1 +
> > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 1067 insertions(+)
> > >  create mode 100644 drivers/dma/sun6i-dma.c
> > 
> > [...]
> > 
> > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > +       if (IS_ERR(sdc->clk)) {
> > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > +               return PTR_ERR(sdc->clk);
> > > +       }
> > > +
> > > +       mux = clk_get(NULL, "ahb1_mux");
> > > +       if (IS_ERR(mux)) {
> > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > +               return PTR_ERR(mux);
> > > +       }
> > > +
> > > +       pll6 = clk_get(NULL, "pll6");
> > > +       if (IS_ERR(pll6)) {
> > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > +               clk_put(mux);
> > > +               return PTR_ERR(pll6);
> > > +       }
> > 
> > I'm slightly confused. The binding listed a single unnamed clock (the
> > AHB clock). What is going on here?
> 
> The device itself needs only a single clock to work...
> 
> > 
> > > +       ret = clk_set_parent(mux, pll6);
> > > +       clk_put(pll6);
> > > +       clk_put(mux);
> > > +
> > > +       if (ret) {
> > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > +               return ret;
> > > +       }
> > 
> > Why do we need to reparent the mux?
> 
> ... but will function only if this clock is derived from PLL6.

Ok, but _why_ is that the case? Could we at least have a comment for
that?

Where does the driver get the named clocks from if they aren't provided
on the device node? Is there a clock-ranges somewhere?

It feels a little fragile to rely on the organisation of the clock tree
and the naming thereof. If the IP block is ever reused on an SoC with a
different clock tree layout then we have to handle things differently.

Cheers,
Mark.

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Rutland]

On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > Hi Maxime,
> > 
> > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > newer A23. Although sharing some similarities with the DMA controller of the
> > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > possible to share the driver for these two.
> > >
> > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > the 16 channels in parallel.
> > >
> > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > ---
> > >  drivers/dma/Kconfig     |    8 +
> > >  drivers/dma/Makefile    |    1 +
> > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > >  3 files changed, 1067 insertions(+)
> > >  create mode 100644 drivers/dma/sun6i-dma.c
> > 
> > [...]
> > 
> > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > +       if (IS_ERR(sdc->clk)) {
> > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > +               return PTR_ERR(sdc->clk);
> > > +       }
> > > +
> > > +       mux = clk_get(NULL, "ahb1_mux");
> > > +       if (IS_ERR(mux)) {
> > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > +               return PTR_ERR(mux);
> > > +       }
> > > +
> > > +       pll6 = clk_get(NULL, "pll6");
> > > +       if (IS_ERR(pll6)) {
> > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > +               clk_put(mux);
> > > +               return PTR_ERR(pll6);
> > > +       }
> > 
> > I'm slightly confused. The binding listed a single unnamed clock (the
> > AHB clock). What is going on here?
> 
> The device itself needs only a single clock to work...
> 
> > 
> > > +       ret = clk_set_parent(mux, pll6);
> > > +       clk_put(pll6);
> > > +       clk_put(mux);
> > > +
> > > +       if (ret) {
> > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > +               return ret;
> > > +       }
> > 
> > Why do we need to reparent the mux?
> 
> ... but will function only if this clock is derived from PLL6.

Ok, but _why_ is that the case? Could we at least have a comment for
that?

Where does the driver get the named clocks from if they aren't provided
on the device node? Is there a clock-ranges somewhere?

It feels a little fragile to rely on the organisation of the clock tree
and the naming thereof. If the IP block is ever reused on an SoC with a
different clock tree layout then we have to handle things differently.

Cheers,
Mark.

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 3221 bytes --]

On Mon, Jun 30, 2014 at 04:33:05PM +0100, Mark Rutland wrote:
> On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> > On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > > Hi Maxime,
> > > 
> > > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > > newer A23. Although sharing some similarities with the DMA controller of the
> > > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > > possible to share the driver for these two.
> > > >
> > > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > > the 16 channels in parallel.
> > > >
> > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > > ---
> > > >  drivers/dma/Kconfig     |    8 +
> > > >  drivers/dma/Makefile    |    1 +
> > > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > > >  3 files changed, 1067 insertions(+)
> > > >  create mode 100644 drivers/dma/sun6i-dma.c
> > > 
> > > [...]
> > > 
> > > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > +       if (IS_ERR(sdc->clk)) {
> > > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > > +               return PTR_ERR(sdc->clk);
> > > > +       }
> > > > +
> > > > +       mux = clk_get(NULL, "ahb1_mux");
> > > > +       if (IS_ERR(mux)) {
> > > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > > +               return PTR_ERR(mux);
> > > > +       }
> > > > +
> > > > +       pll6 = clk_get(NULL, "pll6");
> > > > +       if (IS_ERR(pll6)) {
> > > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > > +               clk_put(mux);
> > > > +               return PTR_ERR(pll6);
> > > > +       }
> > > 
> > > I'm slightly confused. The binding listed a single unnamed clock (the
> > > AHB clock). What is going on here?
> > 
> > The device itself needs only a single clock to work...
> > 
> > > 
> > > > +       ret = clk_set_parent(mux, pll6);
> > > > +       clk_put(pll6);
> > > > +       clk_put(mux);
> > > > +
> > > > +       if (ret) {
> > > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > > +               return ret;
> > > > +       }
> > > 
> > > Why do we need to reparent the mux?
> > 
> > ... but will function only if this clock is derived from PLL6.
> 
> Ok, but _why_ is that the case? Could we at least have a comment for
> that?

I have no idea, sorry.

> Where does the driver get the named clocks from if they aren't provided
> on the device node? Is there a clock-ranges somewhere?

No, it just looks up the global clock name.

> It feels a little fragile to rely on the organisation of the clock tree
> and the naming thereof. If the IP block is ever reused on an SoC with a
> different clock tree layout then we have to handle things differently.

What do you suggest then?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

On Mon, Jun 30, 2014 at 04:33:05PM +0100, Mark Rutland wrote:
> On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> > On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > > Hi Maxime,
> > > 
> > > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > > newer A23. Although sharing some similarities with the DMA controller of the
> > > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > > possible to share the driver for these two.
> > > >
> > > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > > the 16 channels in parallel.
> > > >
> > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > > ---
> > > >  drivers/dma/Kconfig     |    8 +
> > > >  drivers/dma/Makefile    |    1 +
> > > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > > >  3 files changed, 1067 insertions(+)
> > > >  create mode 100644 drivers/dma/sun6i-dma.c
> > > 
> > > [...]
> > > 
> > > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > +       if (IS_ERR(sdc->clk)) {
> > > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > > +               return PTR_ERR(sdc->clk);
> > > > +       }
> > > > +
> > > > +       mux = clk_get(NULL, "ahb1_mux");
> > > > +       if (IS_ERR(mux)) {
> > > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > > +               return PTR_ERR(mux);
> > > > +       }
> > > > +
> > > > +       pll6 = clk_get(NULL, "pll6");
> > > > +       if (IS_ERR(pll6)) {
> > > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > > +               clk_put(mux);
> > > > +               return PTR_ERR(pll6);
> > > > +       }
> > > 
> > > I'm slightly confused. The binding listed a single unnamed clock (the
> > > AHB clock). What is going on here?
> > 
> > The device itself needs only a single clock to work...
> > 
> > > 
> > > > +       ret = clk_set_parent(mux, pll6);
> > > > +       clk_put(pll6);
> > > > +       clk_put(mux);
> > > > +
> > > > +       if (ret) {
> > > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > > +               return ret;
> > > > +       }
> > > 
> > > Why do we need to reparent the mux?
> > 
> > ... but will function only if this clock is derived from PLL6.
> 
> Ok, but _why_ is that the case? Could we at least have a comment for
> that?

I have no idea, sorry.

> Where does the driver get the named clocks from if they aren't provided
> on the device node? Is there a clock-ranges somewhere?

No, it just looks up the global clock name.

> It feels a little fragile to rely on the organisation of the clock tree
> and the naming thereof. If the IP block is ever reused on an SoC with a
> different clock tree layout then we have to handle things differently.

What do you suggest then?

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140701/66f06a27/attachment.sig>

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Rutland]

On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:
> On Mon, Jun 30, 2014 at 04:33:05PM +0100, Mark Rutland wrote:
> > On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> > > On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > > > Hi Maxime,
> > > > 
> > > > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > > > newer A23. Although sharing some similarities with the DMA controller of the
> > > > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > > > possible to share the driver for these two.
> > > > >
> > > > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > > > the 16 channels in parallel.
> > > > >
> > > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > > > ---
> > > > >  drivers/dma/Kconfig     |    8 +
> > > > >  drivers/dma/Makefile    |    1 +
> > > > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > > > >  3 files changed, 1067 insertions(+)
> > > > >  create mode 100644 drivers/dma/sun6i-dma.c
> > > > 
> > > > [...]
> > > > 
> > > > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > > +       if (IS_ERR(sdc->clk)) {
> > > > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > > > +               return PTR_ERR(sdc->clk);
> > > > > +       }
> > > > > +
> > > > > +       mux = clk_get(NULL, "ahb1_mux");
> > > > > +       if (IS_ERR(mux)) {
> > > > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > > > +               return PTR_ERR(mux);
> > > > > +       }
> > > > > +
> > > > > +       pll6 = clk_get(NULL, "pll6");
> > > > > +       if (IS_ERR(pll6)) {
> > > > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > > > +               clk_put(mux);
> > > > > +               return PTR_ERR(pll6);
> > > > > +       }
> > > > 
> > > > I'm slightly confused. The binding listed a single unnamed clock (the
> > > > AHB clock). What is going on here?
> > > 
> > > The device itself needs only a single clock to work...
> > > 
> > > > 
> > > > > +       ret = clk_set_parent(mux, pll6);
> > > > > +       clk_put(pll6);
> > > > > +       clk_put(mux);
> > > > > +
> > > > > +       if (ret) {
> > > > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > > > +               return ret;
> > > > > +       }
> > > > 
> > > > Why do we need to reparent the mux?
> > > 
> > > ... but will function only if this clock is derived from PLL6.
> > 
> > Ok, but _why_ is that the case? Could we at least have a comment for
> > that?
> 
> I have no idea, sorry.

Oh no :(

Where did this requirement turn up? Did an issue crop up in testing and
using PLL6 just happened to work, or does some manual somewhere say that
the device must have its clock derived from PLL6 without further
explanation?

Does PLL6 drive some other clock that the DMA clock needs to stay in
sync with, possibly?

> > Where does the driver get the named clocks from if they aren't provided
> > on the device node? Is there a clock-ranges somewhere?
> 
> No, it just looks up the global clock name.

Ok.

> > It feels a little fragile to rely on the organisation of the clock tree
> > and the naming thereof. If the IP block is ever reused on an SoC with a
> > different clock tree layout then we have to handle things differently.
> 
> What do you suggest then?

I will admit that I don't have a better suggestion.

Without knowing which particular constraint on the mux parent clock we
care about it's difficult to suggest anything useful.

Mark.

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Rutland]

On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:
> On Mon, Jun 30, 2014 at 04:33:05PM +0100, Mark Rutland wrote:
> > On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> > > On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > > > Hi Maxime,
> > > > 
> > > > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > > > newer A23. Although sharing some similarities with the DMA controller of the
> > > > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > > > possible to share the driver for these two.
> > > > >
> > > > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > > > the 16 channels in parallel.
> > > > >
> > > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > > > ---
> > > > >  drivers/dma/Kconfig     |    8 +
> > > > >  drivers/dma/Makefile    |    1 +
> > > > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > > > >  3 files changed, 1067 insertions(+)
> > > > >  create mode 100644 drivers/dma/sun6i-dma.c
> > > > 
> > > > [...]
> > > > 
> > > > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > > +       if (IS_ERR(sdc->clk)) {
> > > > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > > > +               return PTR_ERR(sdc->clk);
> > > > > +       }
> > > > > +
> > > > > +       mux = clk_get(NULL, "ahb1_mux");
> > > > > +       if (IS_ERR(mux)) {
> > > > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > > > +               return PTR_ERR(mux);
> > > > > +       }
> > > > > +
> > > > > +       pll6 = clk_get(NULL, "pll6");
> > > > > +       if (IS_ERR(pll6)) {
> > > > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > > > +               clk_put(mux);
> > > > > +               return PTR_ERR(pll6);
> > > > > +       }
> > > > 
> > > > I'm slightly confused. The binding listed a single unnamed clock (the
> > > > AHB clock). What is going on here?
> > > 
> > > The device itself needs only a single clock to work...
> > > 
> > > > 
> > > > > +       ret = clk_set_parent(mux, pll6);
> > > > > +       clk_put(pll6);
> > > > > +       clk_put(mux);
> > > > > +
> > > > > +       if (ret) {
> > > > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > > > +               return ret;
> > > > > +       }
> > > > 
> > > > Why do we need to reparent the mux?
> > > 
> > > ... but will function only if this clock is derived from PLL6.
> > 
> > Ok, but _why_ is that the case? Could we at least have a comment for
> > that?
> 
> I have no idea, sorry.

Oh no :(

Where did this requirement turn up? Did an issue crop up in testing and
using PLL6 just happened to work, or does some manual somewhere say that
the device must have its clock derived from PLL6 without further
explanation?

Does PLL6 drive some other clock that the DMA clock needs to stay in
sync with, possibly?

> > Where does the driver get the named clocks from if they aren't provided
> > on the device node? Is there a clock-ranges somewhere?
> 
> No, it just looks up the global clock name.

Ok.

> > It feels a little fragile to rely on the organisation of the clock tree
> > and the naming thereof. If the IP block is ever reused on an SoC with a
> > different clock tree layout then we have to handle things differently.
> 
> What do you suggest then?

I will admit that I don't have a better suggestion.

Without knowing which particular constraint on the mux parent clock we
care about it's difficult to suggest anything useful.

Mark.

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 4950 bytes --]

Hi Mark,

On Tue, Jul 01, 2014 at 01:48:52PM +0100, Mark Rutland wrote:
> On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:
> > On Mon, Jun 30, 2014 at 04:33:05PM +0100, Mark Rutland wrote:
> > > On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> > > > On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > > > > Hi Maxime,
> > > > > 
> > > > > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > > > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > > > > newer A23. Although sharing some similarities with the DMA controller of the
> > > > > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > > > > possible to share the driver for these two.
> > > > > >
> > > > > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > > > > the 16 channels in parallel.
> > > > > >
> > > > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > > > > ---
> > > > > >  drivers/dma/Kconfig     |    8 +
> > > > > >  drivers/dma/Makefile    |    1 +
> > > > > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > > > > >  3 files changed, 1067 insertions(+)
> > > > > >  create mode 100644 drivers/dma/sun6i-dma.c
> > > > > 
> > > > > [...]
> > > > > 
> > > > > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > > > +       if (IS_ERR(sdc->clk)) {
> > > > > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > > > > +               return PTR_ERR(sdc->clk);
> > > > > > +       }
> > > > > > +
> > > > > > +       mux = clk_get(NULL, "ahb1_mux");
> > > > > > +       if (IS_ERR(mux)) {
> > > > > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > > > > +               return PTR_ERR(mux);
> > > > > > +       }
> > > > > > +
> > > > > > +       pll6 = clk_get(NULL, "pll6");
> > > > > > +       if (IS_ERR(pll6)) {
> > > > > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > > > > +               clk_put(mux);
> > > > > > +               return PTR_ERR(pll6);
> > > > > > +       }
> > > > > 
> > > > > I'm slightly confused. The binding listed a single unnamed clock (the
> > > > > AHB clock). What is going on here?
> > > > 
> > > > The device itself needs only a single clock to work...
> > > > 
> > > > > 
> > > > > > +       ret = clk_set_parent(mux, pll6);
> > > > > > +       clk_put(pll6);
> > > > > > +       clk_put(mux);
> > > > > > +
> > > > > > +       if (ret) {
> > > > > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > > > > +               return ret;
> > > > > > +       }
> > > > > 
> > > > > Why do we need to reparent the mux?
> > > > 
> > > > ... but will function only if this clock is derived from PLL6.
> > > 
> > > Ok, but _why_ is that the case? Could we at least have a comment for
> > > that?
> > 
> > I have no idea, sorry.
> 
> Oh no :(
> 
> Where did this requirement turn up? Did an issue crop up in testing and
> using PLL6 just happened to work, or does some manual somewhere say that
> the device must have its clock derived from PLL6 without further
> explanation?

I first tried with the default clocks (the 24MHz oscillator) and only
transfers to devices and/or SRAM we working, but transfers from/to the
DRAM were not. Switching to PLL6 was making everything work fine. It
seems to be a bug in the A31 itself, but I don't have much details
yet.

> Does PLL6 drive some other clock that the DMA clock needs to stay in
> sync with, possibly?

PLL6 also drives some peripherals directly yes (such as the MMC or the
SPI controllers), but since I tested this using the SPI, with the main
oscillator as a source for both, I don't think it's related to
that. Or at least, not as directly related as what you were
suggesting.

> 
> > > Where does the driver get the named clocks from if they aren't provided
> > > on the device node? Is there a clock-ranges somewhere?
> > 
> > No, it just looks up the global clock name.
> 
> Ok.
> 
> > > It feels a little fragile to rely on the organisation of the clock tree
> > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > different clock tree layout then we have to handle things differently.
> > 
> > What do you suggest then?
> 
> I will admit that I don't have a better suggestion.
> 
> Without knowing which particular constraint on the mux parent clock we
> care about it's difficult to suggest anything useful.

Well, I first made it into the mach- directory, and then was told to
move it in the driver itself, so we're kind of running out of options
:)

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

Hi Mark,

On Tue, Jul 01, 2014 at 01:48:52PM +0100, Mark Rutland wrote:
> On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:
> > On Mon, Jun 30, 2014 at 04:33:05PM +0100, Mark Rutland wrote:
> > > On Mon, Jun 30, 2014 at 04:19:06PM +0100, Maxime Ripard wrote:
> > > > On Mon, Jun 30, 2014 at 03:20:54PM +0100, Mark Rutland wrote:
> > > > > Hi Maxime,
> > > > > 
> > > > > On Mon, Jun 30, 2014 at 02:20:54PM +0100, Maxime Ripard wrote:
> > > > > > The Allwinner A31 has a 16 channels DMA controller that it shares with the
> > > > > > newer A23. Although sharing some similarities with the DMA controller of the
> > > > > > older Allwinner SoCs, it's significantly different, I don't expect it to be
> > > > > > possible to share the driver for these two.
> > > > > >
> > > > > > The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> > > > > > the 16 channels in parallel.
> > > > > >
> > > > > > Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> > > > > > Acked-by: Arnd Bergmann <arnd@arndb.de>
> > > > > > ---
> > > > > >  drivers/dma/Kconfig     |    8 +
> > > > > >  drivers/dma/Makefile    |    1 +
> > > > > >  drivers/dma/sun6i-dma.c | 1058 +++++++++++++++++++++++++++++++++++++++++++++++
> > > > > >  3 files changed, 1067 insertions(+)
> > > > > >  create mode 100644 drivers/dma/sun6i-dma.c
> > > > > 
> > > > > [...]
> > > > > 
> > > > > > +       sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > > > > > +       if (IS_ERR(sdc->clk)) {
> > > > > > +               dev_err(&pdev->dev, "No clock specified\n");
> > > > > > +               return PTR_ERR(sdc->clk);
> > > > > > +       }
> > > > > > +
> > > > > > +       mux = clk_get(NULL, "ahb1_mux");
> > > > > > +       if (IS_ERR(mux)) {
> > > > > > +               dev_err(&pdev->dev, "Couldn't get AHB1 Mux\n");
> > > > > > +               return PTR_ERR(mux);
> > > > > > +       }
> > > > > > +
> > > > > > +       pll6 = clk_get(NULL, "pll6");
> > > > > > +       if (IS_ERR(pll6)) {
> > > > > > +               dev_err(&pdev->dev, "Couldn't get PLL6\n");
> > > > > > +               clk_put(mux);
> > > > > > +               return PTR_ERR(pll6);
> > > > > > +       }
> > > > > 
> > > > > I'm slightly confused. The binding listed a single unnamed clock (the
> > > > > AHB clock). What is going on here?
> > > > 
> > > > The device itself needs only a single clock to work...
> > > > 
> > > > > 
> > > > > > +       ret = clk_set_parent(mux, pll6);
> > > > > > +       clk_put(pll6);
> > > > > > +       clk_put(mux);
> > > > > > +
> > > > > > +       if (ret) {
> > > > > > +               dev_err(&pdev->dev, "Couldn't reparent AHB1 on PLL6\n");
> > > > > > +               return ret;
> > > > > > +       }
> > > > > 
> > > > > Why do we need to reparent the mux?
> > > > 
> > > > ... but will function only if this clock is derived from PLL6.
> > > 
> > > Ok, but _why_ is that the case? Could we at least have a comment for
> > > that?
> > 
> > I have no idea, sorry.
> 
> Oh no :(
> 
> Where did this requirement turn up? Did an issue crop up in testing and
> using PLL6 just happened to work, or does some manual somewhere say that
> the device must have its clock derived from PLL6 without further
> explanation?

I first tried with the default clocks (the 24MHz oscillator) and only
transfers to devices and/or SRAM we working, but transfers from/to the
DRAM were not. Switching to PLL6 was making everything work fine. It
seems to be a bug in the A31 itself, but I don't have much details
yet.

> Does PLL6 drive some other clock that the DMA clock needs to stay in
> sync with, possibly?

PLL6 also drives some peripherals directly yes (such as the MMC or the
SPI controllers), but since I tested this using the SPI, with the main
oscillator as a source for both, I don't think it's related to
that. Or at least, not as directly related as what you were
suggesting.

> 
> > > Where does the driver get the named clocks from if they aren't provided
> > > on the device node? Is there a clock-ranges somewhere?
> > 
> > No, it just looks up the global clock name.
> 
> Ok.
> 
> > > It feels a little fragile to rely on the organisation of the clock tree
> > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > different clock tree layout then we have to handle things differently.
> > 
> > What do you suggest then?
> 
> I will admit that I don't have a better suggestion.
> 
> Without knowing which particular constraint on the mux parent clock we
> care about it's difficult to suggest anything useful.

Well, I first made it into the mach- directory, and then was told to
move it in the driver itself, so we're kind of running out of options
:)

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140704/1b289109/attachment.sig>

Re: [linux-sunxi] [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Emilio López]

Hi Maxime,

El 30/06/14 10:20, Maxime Ripard escribió:
> The Allwinner A31 has a 16 channels DMA controller that it shares with the
> newer A23. Although sharing some similarities with the DMA controller of the
> older Allwinner SoCs, it's significantly different, I don't expect it to be
> possible to share the driver for these two.
>
> The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> the 16 channels in parallel.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> ---
(...)
> +
> +static struct of_device_id sun6i_dma_match[] = {
> +	{ .compatible = "allwinner,sun6i-a31-dma" }
> +};

The empty sentinel is missing here

Cheers,

Emilio

[linux-sunxi] [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Emilio López]

Hi Maxime,

El 30/06/14 10:20, Maxime Ripard escribi?:
> The Allwinner A31 has a 16 channels DMA controller that it shares with the
> newer A23. Although sharing some similarities with the DMA controller of the
> older Allwinner SoCs, it's significantly different, I don't expect it to be
> possible to share the driver for these two.
>
> The A31 Controller is able to memory-to-memory or memory-to-device transfers on
> the 16 channels in parallel.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> ---
(...)
> +
> +static struct of_device_id sun6i_dma_match[] = {
> +	{ .compatible = "allwinner,sun6i-a31-dma" }
> +};

The empty sentinel is missing here

Cheers,

Emilio

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Arnd Bergmann]

On Friday 04 July 2014, Maxime Ripard wrote:
> > > > It feels a little fragile to rely on the organisation of the clock tree
> > > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > > different clock tree layout then we have to handle things differently.
> > > 
> > > What do you suggest then?
> > 
> > I will admit that I don't have a better suggestion.
> > 
> > Without knowing which particular constraint on the mux parent clock we
> > care about it's difficult to suggest anything useful.
> 
> Well, I first made it into the mach- directory, and then was told to
> move it in the driver itself, so we're kind of running out of options
> :)

How about having a property in the clock provider node that forces a
specific value for the mux? I think that's generally the preferred solution
for any clock settings that go beyond what an OS can be expected to figure
out for itself.

	Arnd

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Arnd Bergmann]

On Friday 04 July 2014, Maxime Ripard wrote:
> > > > It feels a little fragile to rely on the organisation of the clock tree
> > > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > > different clock tree layout then we have to handle things differently.
> > > 
> > > What do you suggest then?
> > 
> > I will admit that I don't have a better suggestion.
> > 
> > Without knowing which particular constraint on the mux parent clock we
> > care about it's difficult to suggest anything useful.
> 
> Well, I first made it into the mach- directory, and then was told to
> move it in the driver itself, so we're kind of running out of options
> :)

How about having a property in the clock provider node that forces a
specific value for the mux? I think that's generally the preferred solution
for any clock settings that go beyond what an OS can be expected to figure
out for itself.

	Arnd

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 1647 bytes --]

On Sun, Jul 06, 2014 at 05:22:00PM +0200, Arnd Bergmann wrote:
> On Friday 04 July 2014, Maxime Ripard wrote:
> > > > > It feels a little fragile to rely on the organisation of the clock tree
> > > > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > > > different clock tree layout then we have to handle things differently.
> > > > 
> > > > What do you suggest then?
> > > 
> > > I will admit that I don't have a better suggestion.
> > > 
> > > Without knowing which particular constraint on the mux parent clock we
> > > care about it's difficult to suggest anything useful.
> > 
> > Well, I first made it into the mach- directory, and then was told to
> > move it in the driver itself, so we're kind of running out of options
> > :)
> 
> How about having a property in the clock provider node that forces a
> specific value for the mux? I think that's generally the preferred solution
> for any clock settings that go beyond what an OS can be expected to figure
> out for itself.

Except that we don't really care about the parenting if the device
isn't going to be used, so putting this property on the clock provider
doesn't look that good. Plus, in the case where we have multiple
clocks defined in a single node, it wouldn't work that great.

However, I'm not convinced that it should be on the device node
either, because we could end up having conflicts between devices.

I don't know, some C code seems like the easier and more flexible
solution here.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

On Sun, Jul 06, 2014 at 05:22:00PM +0200, Arnd Bergmann wrote:
> On Friday 04 July 2014, Maxime Ripard wrote:
> > > > > It feels a little fragile to rely on the organisation of the clock tree
> > > > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > > > different clock tree layout then we have to handle things differently.
> > > > 
> > > > What do you suggest then?
> > > 
> > > I will admit that I don't have a better suggestion.
> > > 
> > > Without knowing which particular constraint on the mux parent clock we
> > > care about it's difficult to suggest anything useful.
> > 
> > Well, I first made it into the mach- directory, and then was told to
> > move it in the driver itself, so we're kind of running out of options
> > :)
> 
> How about having a property in the clock provider node that forces a
> specific value for the mux? I think that's generally the preferred solution
> for any clock settings that go beyond what an OS can be expected to figure
> out for itself.

Except that we don't really care about the parenting if the device
isn't going to be used, so putting this property on the clock provider
doesn't look that good. Plus, in the case where we have multiple
clocks defined in a single node, it wouldn't work that great.

However, I'm not convinced that it should be on the device node
either, because we could end up having conflicts between devices.

I don't know, some C code seems like the easier and more flexible
solution here.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140707/3ed290bb/attachment.sig>

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 914 bytes --]

On Tue, Jul 01, 2014 at 01:48:52PM +0100, Mark Rutland wrote:
> On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:

> > > It feels a little fragile to rely on the organisation of the clock tree
> > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > different clock tree layout then we have to handle things differently.
> > 
> > What do you suggest then?
> 
> I will admit that I don't have a better suggestion.
> 
> Without knowing which particular constraint on the mux parent clock we
> care about it's difficult to suggest anything useful.

There's supposed to be facilities appearing in the generic clock code
for specifying default clock tree configurations via the DT - it's quite
a common requirement after all.  It sounds like that should be able to
do the job here.  Not sure if these have gone in yet or not but there's
quite a bit of demand.

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Brown]

On Tue, Jul 01, 2014 at 01:48:52PM +0100, Mark Rutland wrote:
> On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:

> > > It feels a little fragile to rely on the organisation of the clock tree
> > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > different clock tree layout then we have to handle things differently.
> > 
> > What do you suggest then?
> 
> I will admit that I don't have a better suggestion.
> 
> Without knowing which particular constraint on the mux parent clock we
> care about it's difficult to suggest anything useful.

There's supposed to be facilities appearing in the generic clock code
for specifying default clock tree configurations via the DT - it's quite
a common requirement after all.  It sounds like that should be able to
do the job here.  Not sure if these have gone in yet or not but there's
quite a bit of demand.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140727/4cb178f7/attachment.sig>

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

[-- Attachment #1: Type: text/plain, Size: 1188 bytes --]

Hi Mark,

On Sun, Jul 27, 2014 at 07:49:42PM +0100, Mark Brown wrote:
> On Tue, Jul 01, 2014 at 01:48:52PM +0100, Mark Rutland wrote:
> > On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:
> 
> > > > It feels a little fragile to rely on the organisation of the clock tree
> > > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > > different clock tree layout then we have to handle things differently.
> > > 
> > > What do you suggest then?
> > 
> > I will admit that I don't have a better suggestion.
> > 
> > Without knowing which particular constraint on the mux parent clock we
> > care about it's difficult to suggest anything useful.
> 
> There's supposed to be facilities appearing in the generic clock code
> for specifying default clock tree configurations via the DT - it's quite
> a common requirement after all.  It sounds like that should be able to
> do the job here.  Not sure if these have gone in yet or not but there's
> quite a bit of demand.

As far as I'm aware, it's not been merged yet.

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Maxime Ripard]

Hi Mark,

On Sun, Jul 27, 2014 at 07:49:42PM +0100, Mark Brown wrote:
> On Tue, Jul 01, 2014 at 01:48:52PM +0100, Mark Rutland wrote:
> > On Tue, Jul 01, 2014 at 08:21:19AM +0100, Maxime Ripard wrote:
> 
> > > > It feels a little fragile to rely on the organisation of the clock tree
> > > > and the naming thereof. If the IP block is ever reused on an SoC with a
> > > > different clock tree layout then we have to handle things differently.
> > > 
> > > What do you suggest then?
> > 
> > I will admit that I don't have a better suggestion.
> > 
> > Without knowing which particular constraint on the mux parent clock we
> > care about it's difficult to suggest anything useful.
> 
> There's supposed to be facilities appearing in the generic clock code
> for specifying default clock tree configurations via the DT - it's quite
> a common requirement after all.  It sounds like that should be able to
> do the job here.  Not sure if these have gone in yet or not but there's
> quite a bit of demand.

As far as I'm aware, it's not been merged yet.

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140728/a226f072/attachment.sig>

Re: [PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 607 bytes --]

On Mon, Jul 28, 2014 at 05:09:11PM +0200, Maxime Ripard wrote:
> On Sun, Jul 27, 2014 at 07:49:42PM +0100, Mark Brown wrote:

> > There's supposed to be facilities appearing in the generic clock code
> > for specifying default clock tree configurations via the DT - it's quite
> > a common requirement after all.  It sounds like that should be able to
> > do the job here.  Not sure if these have gone in yet or not but there's
> > quite a bit of demand.

> As far as I'm aware, it's not been merged yet.

Well, another reason to push Mike about it then I guess - there are a
lot of these case cropping up.

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH v10 2/2] dmaengine: sun6i: Add driver for the Allwinner A31 DMA controller

[Mark Brown]

On Mon, Jul 28, 2014 at 05:09:11PM +0200, Maxime Ripard wrote:
> On Sun, Jul 27, 2014 at 07:49:42PM +0100, Mark Brown wrote:

> > There's supposed to be facilities appearing in the generic clock code
> > for specifying default clock tree configurations via the DT - it's quite
> > a common requirement after all.  It sounds like that should be able to
> > do the job here.  Not sure if these have gone in yet or not but there's
> > quite a bit of demand.

> As far as I'm aware, it's not been merged yet.

Well, another reason to push Mike about it then I guess - there are a
lot of these case cropping up.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: Digital signature
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140729/d7dcd600/attachment.sig>