ASoC: fsi: Add DMAEngine support

This patch supports DMAEngine to FSI driver.
It supports only Tx case at this point.
If platform/cpu doesn't support DMAEngine, FSI driver will
use PIO transfer.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 232 insertions, 0 deletions

diff --git a/sound/soc/sh/fsi.c b/sound/soc/sh/fsi.c
index 13746809c27d..378cc5b056d7 100644
--- a/sound/soc/sh/fsi.c
+++ b/sound/soc/sh/fsi.c
@@ -13,8 +13,11 @@
  */
 
 #include <linux/delay.h>
+#include <linux/dma-mapping.h>
 #include <linux/pm_runtime.h>
 #include <linux/io.h>
+#include <linux/scatterlist.h>
+#include <linux/sh_dma.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <sound/soc.h>
@@ -53,6 +56,7 @@
 
 /* DO_FMT */
 /* DI_FMT */
+#define CR_BWS_MASK     (0x3 << 20) /* FSI2 */
 #define CR_BWS_24       (0x0 << 20) /* FSI2 */
 #define CR_BWS_16       (0x1 << 20) /* FSI2 */
 #define CR_BWS_20       (0x2 << 20) /* FSI2 */
@@ -68,6 +72,15 @@
 #define CR_TDM          (0x4 << 4)
 #define CR_TDM_D        (0x5 << 4)
 
+/* OUT_DMAC */
+/* IN_DMAC */
+#define VDMD_MASK       (0x3 << 4)
+#define VDMD_FRONT      (0x0 << 4) /* Package in front */
+#define VDMD_BACK       (0x1 << 4) /* Package in back */
+#define VDMD_STREAM     (0x2 << 4) /* Stream mode(16bit * 2) */
+
+#define DMA_ON          (0x1 << 0)
+
 /* DOFF_CTL */
 /* DIFF_CTL */
 #define IRQ_HALF        0x00100000
@@ -180,6 +193,14 @@ struct fsi_stream {
          */
         struct fsi_stream_handler *handler;
         struct fsi_priv         *priv;
+
+        /*
+         * these are for DMAEngine
+         */
+        struct dma_chan         *chan;
+        struct sh_dmae_slave    slave; /* see fsi_handler_init() */
+        struct tasklet_struct   tasklet;
+        dma_addr_t              dma;
 };
 
 struct fsi_priv {
@@ -889,6 +910,212 @@ static irqreturn_t fsi_interrupt(int irq, void *data)
 }
 
 /*
+ *              dma data transfer handler
+ */
+static int fsi_dma_init(struct fsi_priv *fsi, struct fsi_stream *io)
+{
+        struct snd_pcm_runtime *runtime = io->substream->runtime;
+        struct snd_soc_dai *dai = fsi_get_dai(io->substream);
+        enum dma_data_direction dir = fsi_stream_is_play(fsi, io) ?
+                                DMA_TO_DEVICE : DMA_FROM_DEVICE;
+
+        io->dma = dma_map_single(dai->dev, runtime->dma_area,
+                                 snd_pcm_lib_buffer_bytes(io->substream), dir);
+        return 0;
+}
+
+static int fsi_dma_quit(struct fsi_priv *fsi, struct fsi_stream *io)
+{
+        struct snd_soc_dai *dai = fsi_get_dai(io->substream);
+        enum dma_data_direction dir = fsi_stream_is_play(fsi, io) ?
+                DMA_TO_DEVICE : DMA_FROM_DEVICE;
+
+        dma_unmap_single(dai->dev, io->dma,
+                         snd_pcm_lib_buffer_bytes(io->substream), dir);
+        return 0;
+}
+
+static void fsi_dma_complete(void *data)
+{
+        struct fsi_stream *io = (struct fsi_stream *)data;
+        struct fsi_priv *fsi = fsi_stream_to_priv(io);
+        struct snd_pcm_runtime *runtime = io->substream->runtime;
+        struct snd_soc_dai *dai = fsi_get_dai(io->substream);
+        enum dma_data_direction dir = fsi_stream_is_play(fsi, io) ?
+                DMA_TO_DEVICE : DMA_FROM_DEVICE;
+
+        dma_sync_single_for_cpu(dai->dev, io->dma,
+                        samples_to_bytes(runtime, io->period_samples), dir);
+
+        io->buff_sample_pos += io->period_samples;
+        io->period_pos++;
+
+        if (io->period_pos >= runtime->periods) {
+                io->period_pos = 0;
+                io->buff_sample_pos = 0;
+        }
+
+        fsi_count_fifo_err(fsi);
+        fsi_stream_transfer(io);
+
+        snd_pcm_period_elapsed(io->substream);
+}
+
+static dma_addr_t fsi_dma_get_area(struct fsi_stream *io)
+{
+        struct snd_pcm_runtime *runtime = io->substream->runtime;
+
+        return io->dma + samples_to_bytes(runtime, io->buff_sample_pos);
+}
+
+static void fsi_dma_do_tasklet(unsigned long data)
+{
+        struct fsi_stream *io = (struct fsi_stream *)data;
+        struct fsi_priv *fsi = fsi_stream_to_priv(io);
+        struct dma_chan *chan;
+        struct snd_soc_dai *dai;
+        struct dma_async_tx_descriptor *desc;
+        struct scatterlist sg;
+        struct snd_pcm_runtime *runtime;
+        enum dma_data_direction dir;
+        dma_cookie_t cookie;
+        int is_play = fsi_stream_is_play(fsi, io);
+        int len;
+        dma_addr_t buf;
+
+        if (!fsi_stream_is_working(fsi, io))
+                return;
+
+        dai     = fsi_get_dai(io->substream);
+        chan    = io->chan;
+        runtime = io->substream->runtime;
+        dir     = is_play ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+        len     = samples_to_bytes(runtime, io->period_samples);
+        buf     = fsi_dma_get_area(io);
+
+        dma_sync_single_for_device(dai->dev, io->dma, len, dir);
+
+        sg_init_table(&sg, 1);
+        sg_set_page(&sg, pfn_to_page(PFN_DOWN(buf)),
+                    len , offset_in_page(buf));
+        sg_dma_address(&sg) = buf;
+        sg_dma_len(&sg) = len;
+
+        desc = chan->device->device_prep_slave_sg(chan, &sg, 1, dir,
+                                                  DMA_PREP_INTERRUPT |
+                                                  DMA_CTRL_ACK);
+        if (!desc) {
+                dev_err(dai->dev, "device_prep_slave_sg() fail\n");
+                return;
+        }
+
+        desc->callback          = fsi_dma_complete;
+        desc->callback_param    = io;
+
+        cookie = desc->tx_submit(desc);
+        if (cookie < 0) {
+                dev_err(dai->dev, "tx_submit() fail\n");
+                return;
+        }
+
+        dma_async_issue_pending(chan);
+
+        /*
+         * FIXME
+         *
+         * In DMAEngine case, codec and FSI cannot be started simultaneously
+         * since FSI is using tasklet.
+         * Therefore, in capture case, probably FSI FIFO will have got
+         * overflow error in this point.
+         * in that case, DMA cannot start transfer until error was cleared.
+         */
+        if (!is_play) {
+                if (ERR_OVER & fsi_reg_read(fsi, DIFF_ST)) {
+                        fsi_reg_mask_set(fsi, DIFF_CTL, FIFO_CLR, FIFO_CLR);
+                        fsi_reg_write(fsi, DIFF_ST, 0);
+                }
+        }
+}
+
+static bool fsi_dma_filter(struct dma_chan *chan, void *param)
+{
+        struct sh_dmae_slave *slave = param;
+
+        chan->private = slave;
+
+        return true;
+}
+
+static int fsi_dma_transfer(struct fsi_priv *fsi, struct fsi_stream *io)
+{
+        tasklet_schedule(&io->tasklet);
+
+        return 0;
+}
+
+static void fsi_dma_push_start_stop(struct fsi_priv *fsi, struct fsi_stream *io,
+                                 int start)
+{
+        u32 bws;
+        u32 dma;
+
+        switch (io->sample_width * start) {
+        case 2:
+                bws = CR_BWS_16;
+                dma = VDMD_STREAM | DMA_ON;
+                break;
+        case 4:
+                bws = CR_BWS_24;
+                dma = VDMD_BACK | DMA_ON;
+                break;
+        default:
+                bws = 0;
+                dma = 0;
+        }
+
+        fsi_reg_mask_set(fsi, DO_FMT, CR_BWS_MASK, bws);
+        fsi_reg_write(fsi, OUT_DMAC, dma);
+}
+
+static int fsi_dma_probe(struct fsi_priv *fsi, struct fsi_stream *io)
+{
+        dma_cap_mask_t mask;
+
+        dma_cap_zero(mask);
+        dma_cap_set(DMA_SLAVE, mask);
+
+        io->chan = dma_request_channel(mask, fsi_dma_filter, &io->slave);
+        if (!io->chan)
+                return -EIO;
+
+        tasklet_init(&io->tasklet, fsi_dma_do_tasklet, (unsigned long)io);
+
+        return 0;
+}
+
+static int fsi_dma_remove(struct fsi_priv *fsi, struct fsi_stream *io)
+{
+        tasklet_kill(&io->tasklet);
+
+        fsi_stream_stop(fsi, io);
+
+        if (io->chan)
+                dma_release_channel(io->chan);
+
+        io->chan = NULL;
+        return 0;
+}
+
+static struct fsi_stream_handler fsi_dma_push_handler = {
+        .init           = fsi_dma_init,
+        .quit           = fsi_dma_quit,
+        .probe          = fsi_dma_probe,
+        .transfer       = fsi_dma_transfer,
+        .remove         = fsi_dma_remove,
+        .start_stop     = fsi_dma_push_start_stop,
+};
+
+/*
  *              dai ops
  */
 static void fsi_fifo_init(struct fsi_priv *fsi,
@@ -1304,6 +1531,11 @@ static void fsi_handler_init(struct fsi_priv *fsi)
         fsi->playback.priv      = fsi;
         fsi->capture.handler    = &fsi_pio_pop_handler;  /* default PIO */
         fsi->capture.priv       = fsi;
+
+        if (fsi->info->tx_id) {
+                fsi->playback.slave.slave_id    = fsi->info->tx_id;
+                fsi->playback.handler           = &fsi_dma_push_handler;
+        }
 }
 
 static int fsi_probe(struct platform_device *pdev)