[PATCH v2 1/8] dma: sun4i: Add support for the DMA engine on sun[457]i SoCs
Maxime Ripard
maxime.ripard at free-electrons.com
Thu Jul 17 13:56:39 PDT 2014
On Sun, Jul 06, 2014 at 01:05:08AM -0300, Emilio López wrote:
> This patch adds support for the DMA engine present on Allwinner A10,
> A13, A10S and A20 SoCs. This engine has two kinds of channels: normal
> and dedicated. The main difference is in the mode of operation;
> while a single normal channel may be operating at any given time,
> dedicated channels may operate simultaneously provided there is no
> overlap of source or destination.
>
> Hardware documentation can be found on A10 User Manual (section 12), A13
> User Manual (section 14) and A20 User Manual (section 1.12)
>
> Signed-off-by: Emilio López <emilio at elopez.com.ar>
> ---
>
> Changes from v1:
> * address comments from Chen-Yu and Maxime
> * fix issue converting bus width
> * switch to using a threaded IRQ instead of a tasklet on
> recommendation from Maxime
> * fix issue setting magic timing parameter for SPI transfers
> * fix an issue with list handling reported by the kbuild 0-DAY robot (thanks!)
> * drop a lot of unused #define
> * probably some more stuff I'm forgetting
>
> .../devicetree/bindings/dma/sun4i-dma.txt | 45 +
> drivers/dma/Kconfig | 10 +
> drivers/dma/Makefile | 1 +
> drivers/dma/sun4i-dma.c | 1025 ++++++++++++++++++++
> 4 files changed, 1081 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/dma/sun4i-dma.txt
> create mode 100644 drivers/dma/sun4i-dma.c
>
> diff --git a/Documentation/devicetree/bindings/dma/sun4i-dma.txt b/Documentation/devicetree/bindings/dma/sun4i-dma.txt
> new file mode 100644
> index 0000000..f5661a5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/sun4i-dma.txt
> @@ -0,0 +1,45 @@
> +Allwinner A10 DMA Controller
> +
> +This driver follows the generic DMA bindings defined in dma.txt.
> +
> +Required properties:
> +
> +- compatible: Must be "allwinner,sun4i-a10-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
> +- #dma-cells : Should be 1, a single cell holding a line request number
> +
> +Example:
> + dma: dma-controller at 01c02000 {
> + compatible = "allwinner,sun4i-a10-dma";
> + reg = <0x01c02000 0x1000>;
> + interrupts = <27>;
> + clocks = <&ahb_gates 6>;
> + #dma-cells = <1>;
> + };
> +
> +Clients:
> +
> +DMA clients connected to the Allwinner A10 DMA controller must use the
> +format described in the dma.txt file, using a three-cell specifier for
> +each channel: a phandle plus two integer cells.
> +The three cells in order are:
> +
> +1. A phandle pointing to the DMA controller.
> +2. Whether it is using normal (0) or dedicated (1) channels
> +2. The port ID as specified in the datasheet
> +
> +Example:
> + spi2: spi at 01c17000 {
> + compatible = "allwinner,sun4i-a10-spi";
> + reg = <0x01c17000 0x1000>;
> + interrupts = <0 12 4>;
> + clocks = <&ahb_gates 22>, <&spi2_clk>;
> + clock-names = "ahb", "mod";
> + dmas = <&dma 1 29>, <&dma 1 28>;
> + dma-names = "rx", "tx";
> + status = "disabled";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + };
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index 1eca7b9..cfa6e0a 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -375,6 +375,16 @@ config XILINX_VDMA
> channels, Memory Mapped to Stream (MM2S) and Stream to
> Memory Mapped (S2MM) for the data transfers.
>
> +config SUN4I_DMA
> + tristate "Allwinner A10/A10S/A13/A20 DMA support"
I'm not that fond of having an exhaustive list here. If some other SoC
we didn't thought of or get a new SoC that uses this controller, this
list won't be exhaustive anymore, which is even worse.
Just mention the A10.
> + depends on (MACH_SUN4I || MACH_SUN5I || MACH_SUN7I || (COMPILE_TEST && OF && ARM))
This pretty much defeats the purpose of COMPILE_TEST
> + select DMA_ENGINE
> + select DMA_OF
> + select DMA_VIRTUAL_CHANNELS
I guess you could default to y for the SoCs where it's relevant.
> + help
> + Enable support for the DMA controller present in the sun4i,
> + sun5i and sun7i Allwinner ARM SoCs.
> +
> config DMA_ENGINE
> bool
>
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index c779e1e..430de61 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_SUN4I_DMA) += sun4i-dma.o
> diff --git a/drivers/dma/sun4i-dma.c b/drivers/dma/sun4i-dma.c
> new file mode 100644
> index 0000000..24fa391
> --- /dev/null
> +++ b/drivers/dma/sun4i-dma.c
> @@ -0,0 +1,1025 @@
> +/*
> + * Copyright (C) 2014 Emilio López
> + * Emilio López <emilio at elopez.com.ar>
> + *
> + * 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/bitmap.h>
> +#include <linux/bitops.h>
> +#include <linux/clk.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/slab.h>
> +#include <linux/spinlock.h>
> +
> +#include "virt-dma.h"
> +
> +/** Normal DMA register values **/
> +
> +/* Normal DMA source/destination data request type values */
> +#define NDMA_DRQ_TYPE_SDRAM 0x16
> +#define NDMA_DRQ_TYPE_LIMIT (0x1F + 1)
Hmmm, I'm unsure what this is about... What is it supposed to do, and
how is it different from BIT(5) ?
> +
> +/** Normal DMA register layout **/
> +
> +/* Normal DMA configuration register layout */
> +#define NDMA_CFG_LOADING BIT(31)
> +#define NDMA_CFG_CONT_MODE BIT(30)
> +#define NDMA_CFG_WAIT_STATE(n) ((n) << 27)
> +#define NDMA_CFG_DEST_DATA_WIDTH(width) ((width) << 25)
> +#define NDMA_CFG_DEST_BURST_LENGTH(len) ((len) << 23)
> +#define NDMA_CFG_DEST_NON_SECURE BIT(22)
> +#define NDMA_CFG_DEST_FIXED_ADDR BIT(21)
> +#define NDMA_CFG_DEST_DRQ_TYPE(type) ((type) << 16)
> +#define NDMA_CFG_BYTE_COUNT_MODE_REMAIN BIT(15)
> +#define NDMA_CFG_SRC_DATA_WIDTH(width) ((width) << 9)
> +#define NDMA_CFG_SRC_BURST_LENGTH(len) ((len) << 7)
> +#define NDMA_CFG_SRC_NON_SECURE BIT(6)
> +#define NDMA_CFG_SRC_FIXED_ADDR BIT(5)
> +#define NDMA_CFG_SRC_DRQ_TYPE(type) ((type) << 0)
> +
> +/** Dedicated DMA register values **/
> +
> +/* Dedicated DMA source/destination address mode values */
> +#define DDMA_ADDR_MODE_LINEAR 0
> +#define DDMA_ADDR_MODE_IO 1
> +#define DDMA_ADDR_MODE_HORIZONTAL_PAGE 2
> +#define DDMA_ADDR_MODE_VERTICAL_PAGE 3
> +
> +/* Dedicated DMA source/destination data request type values */
> +#define DDMA_DRQ_TYPE_SDRAM 0x1
> +#define DDMA_DRQ_TYPE_LIMIT (0x1F + 1)
> +
> +/** Dedicated DMA register layout **/
> +
> +/* Dedicated DMA configuration register layout */
> +#define DDMA_CFG_LOADING BIT(31)
> +#define DDMA_CFG_BUSY BIT(30)
> +#define DDMA_CFG_CONT_MODE BIT(29)
> +#define DDMA_CFG_DEST_NON_SECURE BIT(28)
> +#define DDMA_CFG_DEST_DATA_WIDTH(width) ((width) << 25)
> +#define DDMA_CFG_DEST_BURST_LENGTH(len) ((len) << 23)
> +#define DDMA_CFG_DEST_ADDR_MODE(mode) ((mode) << 21)
> +#define DDMA_CFG_DEST_DRQ_TYPE(type) ((type) << 16)
> +#define DDMA_CFG_BYTE_COUNT_MODE_REMAIN BIT(15)
> +#define DDMA_CFG_SRC_NON_SECURE BIT(12)
> +#define DDMA_CFG_SRC_DATA_WIDTH(width) ((width) << 9)
> +#define DDMA_CFG_SRC_BURST_LENGTH(len) ((len) << 7)
> +#define DDMA_CFG_SRC_ADDR_MODE(mode) ((mode) << 5)
> +#define DDMA_CFG_SRC_DRQ_TYPE(type) ((type) << 0)
> +
> +/* Dedicated DMA parameter register layout */
> +#define DDMA_PARA_DEST_DATA_BLK_SIZE(n) (((n) - 1) << 24)
> +#define DDMA_PARA_DEST_WAIT_CYCLES(n) (((n) - 1) << 16)
> +#define DDMA_PARA_SRC_DATA_BLK_SIZE(n) (((n) - 1) << 8)
> +#define DDMA_PARA_SRC_WAIT_CYCLES(n) (((n) - 1) << 0)
> +
> +/** DMA register offsets **/
> +
> +/* General register offsets */
> +#define DMA_IRQ_ENABLE_REG 0x0
> +#define DMA_IRQ_PENDING_STATUS_REG 0x4
> +
> +/* Normal DMA register offsets */
> +#define NDMA_CHANNEL_REG_BASE(n) (0x100 + (n) * 0x20)
> +#define NDMA_CFG_REG 0x0
> +#define NDMA_SRC_ADDR_REG 0x4
> +#define NDMA_DEST_ADDR_REG 0x8
> +#define NDMA_BYTE_COUNT_REG 0xC
> +
> +/* Dedicated DMA register offsets */
> +#define DDMA_CHANNEL_REG_BASE(n) (0x300 + (n) * 0x20)
> +#define DDMA_CFG_REG 0x0
> +#define DDMA_SRC_ADDR_REG 0x4
> +#define DDMA_DEST_ADDR_REG 0x8
> +#define DDMA_BYTE_COUNT_REG 0xC
> +#define DDMA_PARA_REG 0x18
> +
> +/** DMA Driver **/
> +
> +/*
> + * Normal DMA has 8 channels, and Dedicated DMA has another 8, so that's
> + * 16 channels. As for endpoints, there's 29 and 21 respectively. Given
> + * that the Normal DMA endpoints (other than SDRAM) can be used as tx/rx,
> + * we need 78 vchans in total
> + */
> +#define NDMA_NR_MAX_CHANNELS 8
> +#define DDMA_NR_MAX_CHANNELS 8
> +#define DMA_NR_MAX_CHANNELS (NDMA_NR_MAX_CHANNELS + DDMA_NR_MAX_CHANNELS)
> +#define NDMA_NR_MAX_VCHANS (29 * 2 - 1)
> +#define DDMA_NR_MAX_VCHANS 21
> +#define DMA_NR_MAX_VCHANS (NDMA_NR_MAX_VCHANS + DDMA_NR_MAX_VCHANS)
> +
> +/* This set of DDMA timing parameters were found experimentally while
> + * working with the SPI driver and seem to make it behave correctly */
> +#define DDMA_MAGIC_SPI_PARAMETERS (DDMA_PARA_DEST_DATA_BLK_SIZE(1) | \
> + DDMA_PARA_SRC_DATA_BLK_SIZE(1) | \
> + DDMA_PARA_DEST_WAIT_CYCLES(2) | \
> + DDMA_PARA_SRC_WAIT_CYCLES(2))
> +
> +struct sun4i_dma_pchan {
> + /* Register base of channel */
> + void __iomem *base;
> + /* vchan currently being serviced */
> + struct sun4i_dma_vchan *vchan;
> + /* Is this a dedicated pchan? */
> + int is_dedicated;
> +};
> +
> +struct sun4i_dma_vchan {
> + struct virt_dma_chan vc;
> + struct dma_slave_config cfg;
> + struct sun4i_dma_pchan *pchan;
> + struct sun4i_dma_promise *processing;
> + struct sun4i_dma_contract *contract;
> + u8 endpoint;
> + int is_dedicated;
> +};
> +
> +struct sun4i_dma_promise {
> + u32 cfg;
> + u32 para;
> + dma_addr_t src;
> + dma_addr_t dst;
> + size_t len;
> + struct list_head list;
> +};
> +
> +/* A contract is a set of promises */
> +struct sun4i_dma_contract {
> + struct virt_dma_desc vd;
> + struct list_head demands;
> + struct list_head completed_demands;
> +};
> +
> +struct sun4i_dma_dev {
> + DECLARE_BITMAP(pchans_used, DMA_NR_MAX_CHANNELS);
> + struct dma_device slave;
> + struct sun4i_dma_pchan *pchans;
> + struct sun4i_dma_vchan *vchans;
> + void __iomem *base;
> + struct clk *clk;
> + int irq;
> + spinlock_t lock;
> +};
> +
> +static struct sun4i_dma_dev *to_sun4i_dma_dev(struct dma_device *dev)
> +{
> + return container_of(dev, struct sun4i_dma_dev, slave);
> +}
> +
> +static struct sun4i_dma_vchan *to_sun4i_dma_vchan(struct dma_chan *chan)
> +{
> + return container_of(chan, struct sun4i_dma_vchan, vc.chan);
> +}
> +
> +static struct sun4i_dma_contract *to_sun4i_dma_contract(struct virt_dma_desc *vd)
> +{
> + return container_of(vd, struct sun4i_dma_contract, vd);
> +}
> +
> +static struct device *chan2dev(struct dma_chan *chan)
> +{
> + return &chan->dev->device;
> +}
> +
> +static int convert_burst(u32 maxburst)
> +{
> + if (maxburst > 8)
> + return -EINVAL;
> +
> + /* 1 -> 0, 4 -> 1, 8 -> 2 */
> + return (maxburst >> 2);
> +}
> +
> +static int convert_buswidth(enum dma_slave_buswidth addr_width)
> +{
> + if (addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES)
> + return -EINVAL;
> +
> + /* 8 (1 byte) -> 0, 16 (2 bytes) -> 1, 32 (4 bytes) -> 2 */
> + return (addr_width >> 1);
> +}
> +
> +static int sun4i_dma_alloc_chan_resources(struct dma_chan *chan)
> +{
> + return 0;
> +}
> +
> +static void sun4i_dma_free_chan_resources(struct dma_chan *chan)
> +{
> + struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
> +
> + vchan_free_chan_resources(&vchan->vc);
> +}
> +
> +static struct sun4i_dma_pchan *find_and_use_pchan(struct sun4i_dma_dev *priv,
> + struct sun4i_dma_vchan *vchan)
> +{
> + struct sun4i_dma_pchan *pchan = NULL, *pchans = priv->pchans;
> + unsigned long flags;
> + int i, max;
> +
> + spin_lock_irqsave(&priv->lock, flags);
> +
> + /*
> + * pchans 0-NDMA_NR_MAX_CHANNELS are normal, and
> + * NDMA_NR_MAX_CHANNELS+ are dedicated ones
> + */
> + if (vchan->is_dedicated) {
> + i = NDMA_NR_MAX_CHANNELS;
> + max = DMA_NR_MAX_CHANNELS;
> + } else {
> + i = 0;
> + max = NDMA_NR_MAX_CHANNELS;
> + }
> +
> + for_each_clear_bit_from(i, &priv->pchans_used, max) {
> + pchan = &pchans[i];
> + pchan->vchan = vchan;
> + set_bit(i, priv->pchans_used);
> + break;
> + }
> +
> + spin_unlock_irqrestore(&priv->lock, flags);
> +
> + return pchan;
> +}
> +
> +static void release_pchan(struct sun4i_dma_dev *priv,
> + struct sun4i_dma_pchan *pchan)
> +{
> + unsigned long flags;
> + int nr = pchan - priv->pchans;
> +
> + spin_lock_irqsave(&priv->lock, flags);
> +
> + clear_bit(nr, priv->pchans_used);
> + pchan->vchan = NULL;
> +
> + spin_unlock_irqrestore(&priv->lock, flags);
> +}
> +
> +static void configure_pchan(struct sun4i_dma_pchan *pchan,
> + struct sun4i_dma_promise *d)
> +{
> + /*
> + * Configure addresses and misc parameters depending on type
> + * DDMA has an extra field with timing parameters
> + */
> + if (pchan->is_dedicated) {
> + writel_relaxed(d->src, pchan->base + DDMA_SRC_ADDR_REG);
> + writel_relaxed(d->dst, pchan->base + DDMA_DEST_ADDR_REG);
> + writel_relaxed(d->len, pchan->base + DDMA_BYTE_COUNT_REG);
> + writel_relaxed(d->para, pchan->base + DDMA_PARA_REG);
> + writel_relaxed(d->cfg, pchan->base + DDMA_CFG_REG);
> + } else {
> + writel_relaxed(d->src, pchan->base + NDMA_SRC_ADDR_REG);
> + writel_relaxed(d->dst, pchan->base + NDMA_DEST_ADDR_REG);
> + writel_relaxed(d->len, pchan->base + NDMA_BYTE_COUNT_REG);
> + writel_relaxed(d->cfg, pchan->base + NDMA_CFG_REG);
> + }
> +}
> +
> +static void set_pchan_interrupt(struct sun4i_dma_dev *priv,
> + struct sun4i_dma_pchan *pchan,
> + int half, int end)
> +{
> + u32 reg = readl_relaxed(priv->base + DMA_IRQ_ENABLE_REG);
> + int pchan_number = pchan - priv->pchans;
> +
> + if (half)
> + reg |= BIT(pchan_number * 2);
> + else
> + reg &= ~BIT(pchan_number * 2);
> +
> + if (end)
> + reg |= BIT(pchan_number * 2 + 1);
> + else
> + reg &= ~BIT(pchan_number * 2 + 1);
> +
> + writel_relaxed(reg, priv->base + DMA_IRQ_ENABLE_REG);
I don't see any interrupts here. Is this suppose to be called with a
lock taken? If so, it should be mentionned in some comment.
> +}
> +
> +static int execute_vchan_pending(struct sun4i_dma_dev *priv,
> + struct sun4i_dma_vchan *vchan)
> +{
> + struct sun4i_dma_promise *promise = NULL;
> + struct sun4i_dma_contract *contract = NULL;
> + struct sun4i_dma_pchan *pchan;
> + struct virt_dma_desc *vd;
> + int ret;
> +
> + lockdep_assert_held(&vchan->vc.lock);
> +
> + /* We need a pchan to do anything, so secure one if available */
> + pchan = find_and_use_pchan(priv, vchan);
> + if (!pchan)
> + return -EBUSY;
> +
> + /*
> + * Channel endpoints must not be repeated, so if this vchan
> + * has already submitted some work, we can't do anything else
> + */
> + if (vchan->processing) {
> + dev_dbg(chan2dev(&vchan->vc.chan),
> + "processing something to this endpoint already\n");
> + ret = -EBUSY;
> + goto release_pchan;
> + }
> +
> + do {
> + /* Figure out which contract we're working with today */
> + vd = vchan_next_desc(&vchan->vc);
> + if (!vd) {
> + dev_dbg(chan2dev(&vchan->vc.chan),
> + "No pending contract found");
> + ret = 0;
> + goto release_pchan;
> + }
> +
> + contract = to_sun4i_dma_contract(vd);
> + if (list_empty(&contract->demands)) {
> + /* The contract has been completed so mark it as such */
> + list_del(&contract->vd.node);
> + vchan_cookie_complete(&contract->vd);
> + dev_dbg(chan2dev(&vchan->vc.chan),
> + "Empty contract found and marked complete");
> + }
> + } while (list_empty(&contract->demands));
> +
> + /* Now find out what we need to do */
> + promise = list_first_entry(&contract->demands,
> + struct sun4i_dma_promise, list);
> + vchan->processing = promise;
> +
> + /* ... and make it reality */
> + if (promise) {
> + vchan->contract = contract;
> + set_pchan_interrupt(priv, pchan, 0, 1);
> + configure_pchan(pchan, promise);
> + }
> +
> + return 0;
> +
> +release_pchan:
> + release_pchan(priv, pchan);
> + return ret;
> +}
> +
> +/**
> + * Generate a promise, to be used in a normal DMA contract.
> + *
> + * A NDMA promise contains all the information required to program the
> + * normal part of the DMA Engine and get data copied. A non-executed
> + * promise will live in the demands list on a contract. Once it has been
> + * completed, it will be moved to the completed demands list for later freeing.
> + * All linked promises will be freed when the corresponding contract is freed
> + */
> +static struct sun4i_dma_promise *
> +generate_ndma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
> + size_t len, struct dma_slave_config *sconfig)
> +{
> + struct sun4i_dma_promise *promise;
> + int ret;
> +
> + promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
> + if (!promise)
> + return NULL;
> +
> + promise->src = src;
> + promise->dst = dest;
> + promise->len = len;
> + promise->cfg = NDMA_CFG_LOADING | NDMA_CFG_BYTE_COUNT_MODE_REMAIN;
> +
> + /* Source burst */
> + ret = convert_burst(sconfig->src_maxburst);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= NDMA_CFG_SRC_BURST_LENGTH(ret);
> +
> + /* Destination burst */
> + ret = convert_burst(sconfig->dst_maxburst);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= NDMA_CFG_DEST_BURST_LENGTH(ret);
> +
> + /* Source bus width */
> + ret = convert_buswidth(sconfig->src_addr_width);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= NDMA_CFG_SRC_DATA_WIDTH(ret);
> +
> + /* Destination bus width */
> + ret = convert_buswidth(sconfig->dst_addr_width);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= NDMA_CFG_DEST_DATA_WIDTH(ret);
> +
> + return promise;
> +
> +fail:
> + kfree(promise);
> + return NULL;
> +}
> +
> +/**
> + * Generate a promise, to be used in a dedicated DMA contract.
> + *
> + * A DDMA promise contains all the information required to program the
> + * Dedicated part of the DMA Engine and get data copied. A non-executed
> + * promise will live in the demands list on a contract. Once it has been
> + * completed, it will be moved to the completed demands list for later freeing.
> + * All linked promises will be freed when the corresponding contract is freed
> + */
> +static struct sun4i_dma_promise *
> +generate_ddma_promise(struct dma_chan *chan, dma_addr_t src, dma_addr_t dest,
> + size_t len, struct dma_slave_config *sconfig)
> +{
> + struct sun4i_dma_promise *promise;
> + int ret;
> +
> + promise = kzalloc(sizeof(*promise), GFP_NOWAIT);
> + if (!promise)
> + return NULL;
> +
> + promise->src = src;
> + promise->dst = dest;
> + promise->len = len;
> + promise->cfg = DDMA_CFG_LOADING | DDMA_CFG_BYTE_COUNT_MODE_REMAIN;
> +
> + /* Source burst */
> + ret = convert_burst(sconfig->src_maxburst);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= DDMA_CFG_SRC_BURST_LENGTH(ret);
> +
> + /* Destination burst */
> + ret = convert_burst(sconfig->dst_maxburst);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= DDMA_CFG_DEST_BURST_LENGTH(ret);
> +
> + /* Source bus width */
> + ret = convert_buswidth(sconfig->src_addr_width);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= DDMA_CFG_SRC_DATA_WIDTH(ret);
> +
> + /* Destination bus width */
> + ret = convert_buswidth(sconfig->dst_addr_width);
> + if (IS_ERR_VALUE(ret))
> + goto fail;
> + promise->cfg |= DDMA_CFG_DEST_DATA_WIDTH(ret);
> +
> + return promise;
> +
> +fail:
> + kfree(promise);
> + return NULL;
> +}
> +
> +/**
> + * Generate a contract
> + *
> + * Contracts function as DMA descriptors. As our hardware does not support
> + * linked lists, we need to implement SG via software. We use a contract
> + * to hold all the pieces of the request and process them serially one
> + * after another. Each piece is represented as a promise.
> + */
> +static struct sun4i_dma_contract *generate_dma_contract(void)
> +{
> + struct sun4i_dma_contract *contract;
> +
> + contract = kzalloc(sizeof(*contract), GFP_NOWAIT);
> + if (!contract)
> + return NULL;
> +
> + INIT_LIST_HEAD(&contract->demands);
> + INIT_LIST_HEAD(&contract->completed_demands);
> +
> + return contract;
> +}
> +
> +/**
> + * Free a contract and all its associated promises
> + */
> +static void sun4i_dma_free_contract(struct virt_dma_desc *vd)
> +{
> + struct sun4i_dma_contract *contract = to_sun4i_dma_contract(vd);
> + struct sun4i_dma_promise *promise;
> +
> + /* Free all the demands and completed demands */
> + list_for_each_entry(promise, &contract->demands, list) {
> + kfree(promise);
> + }
> +
> + list_for_each_entry(promise, &contract->completed_demands, list) {
> + kfree(promise);
> + }
>
Those brackets are useless.
> + kfree(contract);
> +}
> +
> +static struct dma_async_tx_descriptor *
> +sun4i_dma_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
> + dma_addr_t src, size_t len, unsigned long flags)
> +{
> + struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
> + struct dma_slave_config *sconfig = &vchan->cfg;
> + struct sun4i_dma_promise *promise;
> + struct sun4i_dma_contract *contract;
> +
> + contract = generate_dma_contract();
> + if (!contract)
> + return NULL;
> +
> + if (vchan->is_dedicated)
> + promise = generate_ddma_promise(chan, src, dest, len, sconfig);
> + else
> + promise = generate_ndma_promise(chan, src, dest, len, sconfig);
> +
> + if (!promise) {
> + kfree(contract);
> + return NULL;
> + }
> +
> + /* Configure memcpy mode */
> + if (vchan->is_dedicated) {
> + promise->cfg |= DDMA_CFG_SRC_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM) |
> + DDMA_CFG_DEST_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM);
> + } else {
> + promise->cfg |= NDMA_CFG_SRC_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM) |
> + NDMA_CFG_DEST_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM);
> + }
> +
> + /* Fill the contract with our only promise */
> + list_add_tail(&promise->list, &contract->demands);
> +
> + /* And add it to the vchan */
> + return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
> +}
> +
> +static struct dma_async_tx_descriptor *
> +sun4i_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 sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
> + struct dma_slave_config *sconfig = &vchan->cfg;
> + struct sun4i_dma_promise *promise;
> + struct sun4i_dma_contract *contract;
> + struct scatterlist *sg;
> + dma_addr_t srcaddr, dstaddr;
> + u32 endpoints, para;
> + int i;
> +
> + if (!sgl)
> + return NULL;
> +
> + if (!is_slave_direction(dir)) {
> + dev_err(chan2dev(chan), "Invalid DMA direction\n");
> + return NULL;
> + }
> +
> + contract = generate_dma_contract();
> + if (!contract)
> + return NULL;
> +
> + /* Figure out endpoints */
> + if (vchan->is_dedicated && dir == DMA_MEM_TO_DEV) {
> + endpoints = DDMA_CFG_SRC_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM) |
> + DDMA_CFG_SRC_ADDR_MODE(DDMA_ADDR_MODE_LINEAR) |
> + DDMA_CFG_DEST_DRQ_TYPE(vchan->endpoint) |
> + DDMA_CFG_DEST_ADDR_MODE(DDMA_ADDR_MODE_IO);
> + } else if (!vchan->is_dedicated && dir == DMA_MEM_TO_DEV) {
> + endpoints = NDMA_CFG_SRC_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM) |
> + NDMA_CFG_DEST_DRQ_TYPE(vchan->endpoint) |
> + NDMA_CFG_DEST_FIXED_ADDR;
> + } else if (vchan->is_dedicated) {
> + endpoints = DDMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
> + DDMA_CFG_SRC_ADDR_MODE(DDMA_ADDR_MODE_IO) |
> + DDMA_CFG_DEST_DRQ_TYPE(DDMA_DRQ_TYPE_SDRAM) |
> + DDMA_CFG_DEST_ADDR_MODE(DDMA_ADDR_MODE_LINEAR);
> + } else {
> + endpoints = NDMA_CFG_SRC_DRQ_TYPE(vchan->endpoint) |
> + NDMA_CFG_SRC_FIXED_ADDR |
> + NDMA_CFG_DEST_DRQ_TYPE(NDMA_DRQ_TYPE_SDRAM);
> + }
> +
> + for_each_sg(sgl, sg, sg_len, i) {
> + /* Figure out addresses */
> + if (dir == DMA_MEM_TO_DEV) {
> + srcaddr = sg_dma_address(sg);
> + dstaddr = sconfig->dst_addr;
> + } else {
> + srcaddr = sconfig->src_addr;
> + dstaddr = sg_dma_address(sg);
> + }
> +
> + /* TODO: should this be configurable? */
> + para = DDMA_MAGIC_SPI_PARAMETERS;
What is it? Is it supposed to change from one client device to
another?
> +
> + /* And make a suitable promise */
> + if (vchan->is_dedicated)
> + promise = generate_ddma_promise(chan, srcaddr, dstaddr,
> + sg_dma_len(sg), sconfig);
> + else
> + promise = generate_ndma_promise(chan, srcaddr, dstaddr,
> + sg_dma_len(sg), sconfig);
> +
> + if (!promise)
> + return NULL; /* TODO */
TODO what?
> +
> + promise->cfg |= endpoints;
> + promise->para = para;
> +
> + /* Then add it to the contract */
> + list_add_tail(&promise->list, &contract->demands);
> + }
> +
> + /*
> + * Once we've got all the promises ready, add the contract
> + * to the pending list on the vchan
> + */
> + return vchan_tx_prep(&vchan->vc, &contract->vd, flags);
> +}
> +
> +static int sun4i_dma_terminate_all(struct sun4i_dma_vchan *vchan)
> +{
> + struct sun4i_dma_pchan *pchan = vchan->pchan;
> + LIST_HEAD(head);
> + unsigned long flags, timeout;
> + u32 d_busy = DDMA_CFG_LOADING | DDMA_CFG_BUSY;
> + u32 n_busy = NDMA_CFG_LOADING;
> +
> +
> + spin_lock_irqsave(&vchan->vc.lock, flags);
> + vchan_get_all_descriptors(&vchan->vc, &head);
> + spin_unlock_irqrestore(&vchan->vc.lock, flags);
> +
> + /* If this vchan is operating, wait until it's no longer busy */
> + if (pchan) {
> + timeout = jiffies + msecs_to_jiffies(2000);
> + if (pchan->is_dedicated) {
> + while (readl(pchan->base + DDMA_CFG_REG) & d_busy)
> + if (time_after(jiffies, timeout))
> + return -ETIMEDOUT;
> + } else {
> + while (readl(pchan->base + NDMA_CFG_REG) & n_busy)
> + if (time_after(jiffies, timeout))
> + return -ETIMEDOUT;
> + }
> + }
> +
> + spin_lock_irqsave(&vchan->vc.lock, flags);
> + vchan_dma_desc_free_list(&vchan->vc, &head);
> + spin_unlock_irqrestore(&vchan->vc.lock, flags);
> +
> + return 0;
> +}
> +
> +static int sun4i_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> + unsigned long arg)
> +{
> + struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
> + int ret = 0;
> +
> + switch (cmd) {
> + case DMA_RESUME:
> + case DMA_PAUSE:
> + ret = -EINVAL;
> + break;
> +
> + case DMA_TERMINATE_ALL:
> + dev_dbg(chan2dev(chan), "Terminating everything on channel\n");
> + ret = sun4i_dma_terminate_all(vchan);
> + break;
> +
> + case DMA_SLAVE_CONFIG:
> + memcpy(&vchan->cfg, (void *)arg, sizeof(vchan->cfg));
> + break;
> +
> + default:
> + ret = -ENXIO;
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static struct dma_chan *sun4i_dma_of_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct sun4i_dma_dev *priv = ofdma->of_dma_data;
> + struct sun4i_dma_vchan *vchan;
> + struct dma_chan *chan;
> + u8 is_dedicated = dma_spec->args[0];
> + u8 endpoint = dma_spec->args[1];
> +
> + /* Check if type is Normal or Dedicated */
> + if (is_dedicated != 0 && is_dedicated != 1)
> + return NULL;
> +
> + /* Make sure the endpoint looks sane */
> + if ((is_dedicated && endpoint >= DDMA_DRQ_TYPE_LIMIT) ||
> + (!is_dedicated && endpoint >= NDMA_DRQ_TYPE_LIMIT))
> + return NULL;
> +
> + chan = dma_get_any_slave_channel(&priv->slave);
> + if (!chan)
> + return NULL;
> +
> + /* Assign the endpoint to the vchan */
> + vchan = to_sun4i_dma_vchan(chan);
> + vchan->is_dedicated = is_dedicated;
> + vchan->endpoint = endpoint;
> +
> + return chan;
> +}
> +
> +static enum dma_status sun4i_dma_tx_status(struct dma_chan *chan,
> + dma_cookie_t cookie,
> + struct dma_tx_state *state)
> +{
> + struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
> + struct sun4i_dma_pchan *pchan = vchan->pchan;
> + struct sun4i_dma_contract *contract;
> + struct sun4i_dma_promise *promise;
> + struct virt_dma_desc *vd;
> + unsigned long flags;
> + enum dma_status ret;
> + 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);
> + if (!vd) /* TODO */
TODO what?
> + goto exit;
> + contract = to_sun4i_dma_contract(vd);
> +
> + list_for_each_entry(promise, &contract->demands, list) {
> + bytes += promise->len;
> + }
Useless brackets
> + /*
> + * The hardware is configured to return the remaining byte
> + * quantity. If possible, replace the first listed element's
> + * full size with the actual remaining amount
> + */
> + promise = list_first_entry_or_null(&contract->demands,
> + struct sun4i_dma_promise, list);
> + if (promise && pchan) {
> + bytes -= promise->len;
> + if (pchan->is_dedicated)
> + bytes += readl(pchan->base + DDMA_BYTE_COUNT_REG);
> + else
> + bytes += readl(pchan->base + NDMA_BYTE_COUNT_REG);
> + }
> +
> +exit:
> +
> + dma_set_residue(state, bytes);
> + spin_unlock_irqrestore(&vchan->vc.lock, flags);
> +
> + return ret;
> +}
> +
> +static void sun4i_dma_issue_pending(struct dma_chan *chan)
> +{
> + struct sun4i_dma_dev *priv = to_sun4i_dma_dev(chan->device);
> + struct sun4i_dma_vchan *vchan = to_sun4i_dma_vchan(chan);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&vchan->vc.lock, flags);
> +
> + /*
> + * If there are pending transactions for this vchan, push one of
> + * them into the engine to get the ball rolling.
> + */
> + if (vchan_issue_pending(&vchan->vc))
> + execute_vchan_pending(priv, vchan);
> +
> + spin_unlock_irqrestore(&vchan->vc.lock, flags);
> +}
> +
> +static irqreturn_t sun4i_dma_interrupt(int irq, void *dev_id)
> +{
> + struct sun4i_dma_dev *priv = dev_id;
> + struct sun4i_dma_pchan *pchans = priv->pchans, *pchan;
> + struct sun4i_dma_vchan *vchan;
> + struct sun4i_dma_contract *contract;
> + unsigned long pendirq, irqs;
> + int bit;
> +
> + pendirq = readl_relaxed(priv->base + DMA_IRQ_PENDING_STATUS_REG);
> + irqs = readl_relaxed(priv->base + DMA_IRQ_ENABLE_REG);
> +
> + for_each_set_bit(bit, &pendirq, 32) {
> + pchan = &pchans[bit >> 1];
> + vchan = pchan->vchan;
> + contract = vchan->contract;
> +
> + /*
> + * Disable the IRQ and free the pchan if it's an end
> + * interrupt (odd bit)
> + */
> + if (bit & 1) {
> + spin_lock(&vchan->vc.lock);
> + /*
> + * Move the promise into the completed list now that
> + * we're done with it
> + */
> + list_del(&vchan->processing->list);
> + list_add_tail(&vchan->processing->list, &contract->completed_demands);
> + vchan->processing = NULL;
> + vchan->pchan = NULL;
> + spin_unlock(&vchan->vc.lock);
> +
> + irqs &= ~BIT(bit);
> + release_pchan(priv, pchan);
> + }
> + }
> +
> + writel_relaxed(irqs, priv->base + DMA_IRQ_ENABLE_REG);
> +
> + /* Writing 1 to the pending field will clear the pending interrupt */
> + writel_relaxed(pendirq, priv->base + DMA_IRQ_PENDING_STATUS_REG);
> +
> + return IRQ_WAKE_THREAD;
> +}
> +
> +static irqreturn_t sun4i_dma_submit_work(int irq, void *dev_id)
> +{
> + struct sun4i_dma_dev *priv = dev_id;
> + struct sun4i_dma_vchan *vchan;
> + int i;
> +
> + for (i = 0; i < DMA_NR_MAX_VCHANS; i++) {
> + vchan = &priv->vchans[i];
> + spin_lock_irq(&vchan->vc.lock);
> + execute_vchan_pending(priv, vchan);
> + spin_unlock_irq(&vchan->vc.lock);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int sun4i_dma_probe(struct platform_device *pdev)
> +{
> + struct sun4i_dma_dev *priv;
> + struct resource *res;
> + int i, j, ret;
> +
> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + priv->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(priv->base))
> + return PTR_ERR(priv->base);
> +
> + priv->irq = platform_get_irq(pdev, 0);
> + if (priv->irq < 0) {
> + dev_err(&pdev->dev, "Cannot claim IRQ\n");
> + return priv->irq;
> + }
> +
> + priv->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(priv->clk)) {
> + dev_err(&pdev->dev, "No clock specified\n");
> + return PTR_ERR(priv->clk);
> + }
> +
> + platform_set_drvdata(pdev, priv);
> + spin_lock_init(&priv->lock);
> +
> + dma_cap_zero(priv->slave.cap_mask);
> + dma_cap_set(DMA_PRIVATE, priv->slave.cap_mask);
> + dma_cap_set(DMA_MEMCPY, priv->slave.cap_mask);
> + dma_cap_set(DMA_SLAVE, priv->slave.cap_mask);
> +
> + INIT_LIST_HEAD(&priv->slave.channels);
> + priv->slave.device_alloc_chan_resources = sun4i_dma_alloc_chan_resources;
> + priv->slave.device_free_chan_resources = sun4i_dma_free_chan_resources;
> + priv->slave.device_tx_status = sun4i_dma_tx_status;
> + priv->slave.device_issue_pending = sun4i_dma_issue_pending;
> + priv->slave.device_prep_slave_sg = sun4i_dma_prep_slave_sg;
> + priv->slave.device_prep_dma_memcpy = sun4i_dma_prep_dma_memcpy;
> + priv->slave.device_control = sun4i_dma_control;
> + priv->slave.chancnt = DDMA_NR_MAX_VCHANS;
> +
> + priv->slave.dev = &pdev->dev;
> +
> + priv->pchans = devm_kcalloc(&pdev->dev, DMA_NR_MAX_CHANNELS,
> + sizeof(struct sun4i_dma_pchan), GFP_KERNEL);
> + priv->vchans = devm_kcalloc(&pdev->dev, DMA_NR_MAX_VCHANS,
> + sizeof(struct sun4i_dma_vchan), GFP_KERNEL);
> + if (!priv->vchans || !priv->pchans)
> + return -ENOMEM;
> +
> + /*
> + * [0..NDMA_NR_MAX_CHANNELS) are normal pchans, and
> + * [NDMA_NR_MAX_CHANNELS..DMA_NR_MAX_CHANNELS) are dedicated ones
> + */
> + for (i = 0; i < NDMA_NR_MAX_CHANNELS; i++)
> + priv->pchans[i].base = priv->base + NDMA_CHANNEL_REG_BASE(i);
> +
> + for (j = 0; i < DMA_NR_MAX_CHANNELS; i++, j++) {
> + priv->pchans[i].base = priv->base + DDMA_CHANNEL_REG_BASE(j);
> + priv->pchans[i].is_dedicated = 1;
> + }
> +
> + for (i = 0; i < DMA_NR_MAX_VCHANS; i++) {
> + struct sun4i_dma_vchan *vchan = &priv->vchans[i];
> +
> + spin_lock_init(&vchan->vc.lock);
> + vchan->vc.desc_free = sun4i_dma_free_contract;
> + vchan_init(&vchan->vc, &priv->slave);
> + }
> +
> + ret = clk_prepare_enable(priv->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "Couldn't enable the clock\n");
> + return ret;
> + }
> +
> + ret = devm_request_threaded_irq(&pdev->dev, priv->irq,
> + sun4i_dma_interrupt,
> + sun4i_dma_submit_work,
> + 0, dev_name(&pdev->dev), priv);
> + if (ret) {
> + dev_err(&pdev->dev, "Cannot request IRQ\n");
> + goto err_clk_disable;
> + }
> +
> + ret = dma_async_device_register(&priv->slave);
> + if (ret) {
> + dev_warn(&pdev->dev, "Failed to register DMA engine device\n");
> + goto err_clk_disable;
> + }
> +
> + ret = of_dma_controller_register(pdev->dev.of_node, sun4i_dma_of_xlate,
> + priv);
> + if (ret) {
> + dev_err(&pdev->dev, "of_dma_controller_register failed\n");
> + goto err_dma_unregister;
> + }
> +
> + dev_dbg(&pdev->dev, "Successfully probed SUN4I_DMA\n");
> +
> + return 0;
> +
> +err_dma_unregister:
> + dma_async_device_unregister(&priv->slave);
> +err_clk_disable:
> + clk_disable_unprepare(priv->clk);
> + return ret;
> +}
> +
> +static int sun4i_dma_remove(struct platform_device *pdev)
> +{
> + struct sun4i_dma_dev *priv = platform_get_drvdata(pdev);
> +
> + /* Disable IRQ so no more work is scheduled */
> + disable_irq(priv->irq);
> +
> + of_dma_controller_free(pdev->dev.of_node);
> + dma_async_device_unregister(&priv->slave);
> +
> + clk_disable_unprepare(priv->clk);
> +
> + return 0;
> +}
> +
> +static struct of_device_id sun4i_dma_match[] = {
> + { .compatible = "allwinner,sun4i-a10-dma" },
> + { /* sentinel */ },
> +};
> +
> +static struct platform_driver sun4i_dma_driver = {
> + .probe = sun4i_dma_probe,
> + .remove = sun4i_dma_remove,
> + .driver = {
> + .name = "sun4i-dma",
> + .of_match_table = sun4i_dma_match,
> + },
> +};
> +
> +module_platform_driver(sun4i_dma_driver);
> +
> +MODULE_DESCRIPTION("Allwinner A10 Dedicated DMA Controller Driver");
> +MODULE_AUTHOR("Emilio López <emilio at elopez.com.ar>");
> +MODULE_LICENSE("GPL");
> --
> 2.0.1
Thanks!
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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