ASoC: DaVinci: pcm, fix underrun by using sram

Fix underruns by using dma to copy 1st to sram
in a ping/pong buffer style and then copying from
the sram to the ASP. This also has the advantage
of tolerating very long interrupt latency on dma
completion.

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

4 files changed, 481 insertions, 44 deletions

diff --git a/arch/arm/mach-davinci/include/mach/asp.h b/arch/arm/mach-davinci/include/mach/asp.h
index 019c64733417..e07f70ed7c53 100644
--- a/arch/arm/mach-davinci/include/mach/asp.h
+++ b/arch/arm/mach-davinci/include/mach/asp.h
@@ -57,6 +57,8 @@ struct snd_platform_data {
          * when compared to previous behavior.
          */
         unsigned enable_channel_combine:1;
+        unsigned sram_size_playback;
+        unsigned sram_size_capture;
 
         /* McASP specific fields */
         int tdm_slots;
diff --git a/sound/soc/davinci/davinci-i2s.c b/sound/soc/davinci/davinci-i2s.c
index b2a5372ef72c..6362ca05506e 100644
--- a/sound/soc/davinci/davinci-i2s.c
+++ b/sound/soc/davinci/davinci-i2s.c
@@ -545,8 +545,13 @@ static int davinci_i2s_probe(struct platform_device *pdev)
                 ret = -ENOMEM;
                 goto err_release_region;
         }
-        if (pdata)
+        if (pdata) {
                 dev->enable_channel_combine = pdata->enable_channel_combine;
+                dev->dma_params[SNDRV_PCM_STREAM_PLAYBACK].sram_size =
+                        pdata->sram_size_playback;
+                dev->dma_params[SNDRV_PCM_STREAM_CAPTURE].sram_size =
+                        pdata->sram_size_capture;
+        }
         dev->clk = clk_get(&pdev->dev, NULL);
         if (IS_ERR(dev->clk)) {
                 ret = -ENODEV;
diff --git a/sound/soc/davinci/davinci-pcm.c b/sound/soc/davinci/davinci-pcm.c
index 42a657ea49cb..664d49336508 100644
--- a/sound/soc/davinci/davinci-pcm.c
+++ b/sound/soc/davinci/davinci-pcm.c
@@ -3,6 +3,7 @@
  *
  * Author:      Vladimir Barinov, <vbarinov@embeddedalley.com>
  * Copyright:   (C) 2007 MontaVista Software, Inc., <source@mvista.com>
+ * added SRAM ping/pong (C) 2008 Troy Kisky <troy.kisky@boundarydevices.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -23,10 +24,29 @@
 
 #include <asm/dma.h>
 #include <mach/edma.h>
+#include <mach/sram.h>
 
 #include "davinci-pcm.h"
 
-static struct snd_pcm_hardware davinci_pcm_hardware = {
+#ifdef DEBUG
+static void print_buf_info(int slot, char *name)
+{
+        struct edmacc_param p;
+        if (slot < 0)
+                return;
+        edma_read_slot(slot, &p);
+        printk(KERN_DEBUG "%s: 0x%x, opt=%x, src=%x, a_b_cnt=%x dst=%x\n",
+                        name, slot, p.opt, p.src, p.a_b_cnt, p.dst);
+        printk(KERN_DEBUG "    src_dst_bidx=%x link_bcntrld=%x src_dst_cidx=%x ccnt=%x\n",
+                        p.src_dst_bidx, p.link_bcntrld, p.src_dst_cidx, p.ccnt);
+}
+#else
+static void print_buf_info(int slot, char *name)
+{
+}
+#endif
+
+static struct snd_pcm_hardware pcm_hardware_playback = {
         .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
                  SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
                  SNDRV_PCM_INFO_PAUSE),
@@ -48,14 +68,80 @@ static struct snd_pcm_hardware davinci_pcm_hardware = {
         .fifo_size = 0,
 };
 
+static struct snd_pcm_hardware pcm_hardware_capture = {
+        .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
+                 SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
+                 SNDRV_PCM_INFO_PAUSE),
+        .formats = (SNDRV_PCM_FMTBIT_S16_LE),
+        .rates = (SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000 |
+                  SNDRV_PCM_RATE_22050 | SNDRV_PCM_RATE_32000 |
+                  SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
+                  SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000 |
+                  SNDRV_PCM_RATE_KNOT),
+        .rate_min = 8000,
+        .rate_max = 96000,
+        .channels_min = 2,
+        .channels_max = 2,
+        .buffer_bytes_max = 128 * 1024,
+        .period_bytes_min = 32,
+        .period_bytes_max = 8 * 1024,
+        .periods_min = 16,
+        .periods_max = 255,
+        .fifo_size = 0,
+};
+
+/*
+ * How ping/pong works....
+ *
+ * Playback:
+ * ram_params - copys 2*ping_size from start of SDRAM to iram,
+ *      links to ram_link2
+ * ram_link2 - copys rest of SDRAM to iram in ping_size units,
+ *      links to ram_link
+ * ram_link - copys entire SDRAM to iram in ping_size uints,
+ *      links to self
+ *
+ * asp_params - same as asp_link[0]
+ * asp_link[0] - copys from lower half of iram to asp port
+ *      links to asp_link[1], triggers iram copy event on completion
+ * asp_link[1] - copys from upper half of iram to asp port
+ *      links to asp_link[0], triggers iram copy event on completion
+ *      triggers interrupt only needed to let upper SOC levels update position
+ *      in stream on completion
+ *
+ * When playback is started:
+ *      ram_params started
+ *      asp_params started
+ *
+ * Capture:
+ * ram_params - same as ram_link,
+ *      links to ram_link
+ * ram_link - same as playback
+ *      links to self
+ *
+ * asp_params - same as playback
+ * asp_link[0] - same as playback
+ * asp_link[1] - same as playback
+ *
+ * When capture is started:
+ *      asp_params started
+ */
 struct davinci_runtime_data {
         spinlock_t lock;
         int period;             /* current DMA period */
         int asp_channel;        /* Master DMA channel */
         int asp_link[2];        /* asp parameter link channel, ping/pong */
         struct davinci_pcm_dma_params *params;  /* DMA params */
+        int ram_channel;
+        int ram_link;
+        int ram_link2;
+        struct edmacc_param asp_params;
+        struct edmacc_param ram_params;
 };
 
+/*
+ * Not used with ping/pong
+ */
 static void davinci_pcm_enqueue_dma(struct snd_pcm_substream *substream)
 {
         struct davinci_runtime_data *prtd = substream->runtime->private_data;
@@ -124,41 +210,290 @@ static void davinci_pcm_dma_irq(unsigned link, u16 ch_status, void *data)
         struct snd_pcm_substream *substream = data;
         struct davinci_runtime_data *prtd = substream->runtime->private_data;
 
+        print_buf_info(prtd->ram_channel, "i ram_channel");
         pr_debug("davinci_pcm: link=%d, status=0x%x\n", link, ch_status);
 
         if (unlikely(ch_status != DMA_COMPLETE))
                 return;
 
         if (snd_pcm_running(substream)) {
+                if (prtd->ram_channel < 0) {
+                        /* No ping/pong must fix up link dma data*/
+                        spin_lock(&prtd->lock);
+                        davinci_pcm_enqueue_dma(substream);
+                        spin_unlock(&prtd->lock);
+                }
                 snd_pcm_period_elapsed(substream);
+        }
+}
+
+static int allocate_sram(struct snd_pcm_substream *substream, unsigned size,
+                struct snd_pcm_hardware *ppcm)
+{
+        struct snd_dma_buffer *buf = &substream->dma_buffer;
+        struct snd_dma_buffer *iram_dma = NULL;
+        dma_addr_t iram_phys = 0;
+        void *iram_virt = NULL;
+
+        if (buf->private_data || !size)
+                return 0;
+
+        ppcm->period_bytes_max = size;
+        iram_virt = sram_alloc(size, &iram_phys);
+        if (!iram_virt)
+                goto exit1;
+        iram_dma = kzalloc(sizeof(*iram_dma), GFP_KERNEL);
+        if (!iram_dma)
+                goto exit2;
+        iram_dma->area = iram_virt;
+        iram_dma->addr = iram_phys;
+        memset(iram_dma->area, 0, size);
+        iram_dma->bytes = size;
+        buf->private_data = iram_dma;
+        return 0;
+exit2:
+        if (iram_virt)
+                sram_free(iram_virt, size);
+exit1:
+        return -ENOMEM;
+}
 
-                spin_lock(&prtd->lock);
-                davinci_pcm_enqueue_dma(substream);
-                spin_unlock(&prtd->lock);
+/*
+ * Only used with ping/pong.
+ * This is called after runtime->dma_addr, period_bytes and data_type are valid
+ */
+static int ping_pong_dma_setup(struct snd_pcm_substream *substream)
+{
+        unsigned short ram_src_cidx, ram_dst_cidx;
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct davinci_runtime_data *prtd = runtime->private_data;
+        struct snd_dma_buffer *iram_dma =
+                (struct snd_dma_buffer *)substream->dma_buffer.private_data;
+        struct davinci_pcm_dma_params *params = prtd->params;
+        unsigned int data_type = params->data_type;
+        unsigned int acnt = params->acnt;
+        /* divide by 2 for ping/pong */
+        unsigned int ping_size = snd_pcm_lib_period_bytes(substream) >> 1;
+        int link = prtd->asp_link[1];
+        unsigned int fifo_level = prtd->params->fifo_level;
+        unsigned int count;
+        if ((data_type == 0) || (data_type > 4)) {
+                printk(KERN_ERR "%s: data_type=%i\n", __func__, data_type);
+                return -EINVAL;
+        }
+        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                dma_addr_t asp_src_pong = iram_dma->addr + ping_size;
+                ram_src_cidx = ping_size;
+                ram_dst_cidx = -ping_size;
+                edma_set_src(link, asp_src_pong, INCR, W8BIT);
+
+                link = prtd->asp_link[0];
+                edma_set_src_index(link, data_type, data_type * fifo_level);
+                link = prtd->asp_link[1];
+                edma_set_src_index(link, data_type, data_type * fifo_level);
+
+                link = prtd->ram_link;
+                edma_set_src(link, runtime->dma_addr, INCR, W32BIT);
+        } else {
+                dma_addr_t asp_dst_pong = iram_dma->addr + ping_size;
+                ram_src_cidx = -ping_size;
+                ram_dst_cidx = ping_size;
+                edma_set_dest(link, asp_dst_pong, INCR, W8BIT);
+
+                link = prtd->asp_link[0];
+                edma_set_dest_index(link, data_type, data_type * fifo_level);
+                link = prtd->asp_link[1];
+                edma_set_dest_index(link, data_type, data_type * fifo_level);
+
+                link = prtd->ram_link;
+                edma_set_dest(link, runtime->dma_addr, INCR, W32BIT);
+        }
+
+        if (!fifo_level) {
+                count = ping_size / data_type;
+                edma_set_transfer_params(prtd->asp_link[0], acnt, count,
+                                1, 0, ASYNC);
+                edma_set_transfer_params(prtd->asp_link[1], acnt, count,
+                                1, 0, ASYNC);
+        } else {
+                count = ping_size / (data_type * fifo_level);
+                edma_set_transfer_params(prtd->asp_link[0], acnt, fifo_level,
+                                count, fifo_level, ABSYNC);
+                edma_set_transfer_params(prtd->asp_link[1], acnt, fifo_level,
+                                count, fifo_level, ABSYNC);
+        }
+
+        link = prtd->ram_link;
+        edma_set_src_index(link, ping_size, ram_src_cidx);
+        edma_set_dest_index(link, ping_size, ram_dst_cidx);
+        edma_set_transfer_params(link, ping_size, 2,
+                        runtime->periods, 2, ASYNC);
+
+        /* init master params */
+        edma_read_slot(prtd->asp_link[0], &prtd->asp_params);
+        edma_read_slot(prtd->ram_link, &prtd->ram_params);
+        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                struct edmacc_param p_ram;
+                /* Copy entire iram buffer before playback started */
+                prtd->ram_params.a_b_cnt = (1 << 16) | (ping_size << 1);
+                /* 0 dst_bidx */
+                prtd->ram_params.src_dst_bidx = (ping_size << 1);
+                /* 0 dst_cidx */
+                prtd->ram_params.src_dst_cidx = (ping_size << 1);
+                prtd->ram_params.ccnt = 1;
+
+                /* Skip 1st period */
+                edma_read_slot(prtd->ram_link, &p_ram);
+                p_ram.src += (ping_size << 1);
+                p_ram.ccnt -= 1;
+                edma_write_slot(prtd->ram_link2, &p_ram);
+                /*
+                 * When 1st started, ram -> iram dma channel will fill the
+                 * entire iram.  Then, whenever a ping/pong asp buffer finishes,
+                 * 1/2 iram will be filled.
+                 */
+                prtd->ram_params.link_bcntrld =
+                        EDMA_CHAN_SLOT(prtd->ram_link2) << 5;
+        }
+        return 0;
+}
+
+/* 1 asp tx or rx channel using 2 parameter channels
+ * 1 ram to/from iram channel using 1 parameter channel
+ *
+ * Playback
+ * ram copy channel kicks off first,
+ * 1st ram copy of entire iram buffer completion kicks off asp channel
+ * asp tcc always kicks off ram copy of 1/2 iram buffer
+ *
+ * Record
+ * asp channel starts, tcc kicks off ram copy
+ */
+static int request_ping_pong(struct snd_pcm_substream *substream,
+                struct davinci_runtime_data *prtd,
+                struct snd_dma_buffer *iram_dma)
+{
+        dma_addr_t asp_src_ping;
+        dma_addr_t asp_dst_ping;
+        int link;
+        struct davinci_pcm_dma_params *params = prtd->params;
+
+        /* Request ram master channel */
+        link = prtd->ram_channel = edma_alloc_channel(EDMA_CHANNEL_ANY,
+                                  davinci_pcm_dma_irq, substream,
+                                  EVENTQ_1);
+        if (link < 0)
+                goto exit1;
+
+        /* Request ram link channel */
+        link = prtd->ram_link = edma_alloc_slot(
+                        EDMA_CTLR(prtd->ram_channel), EDMA_SLOT_ANY);
+        if (link < 0)
+                goto exit2;
+
+        link = prtd->asp_link[1] = edma_alloc_slot(
+                        EDMA_CTLR(prtd->asp_channel), EDMA_SLOT_ANY);
+        if (link < 0)
+                goto exit3;
+
+        prtd->ram_link2 = -1;
+        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                link = prtd->ram_link2 = edma_alloc_slot(
+                        EDMA_CTLR(prtd->ram_channel), EDMA_SLOT_ANY);
+                if (link < 0)
+                        goto exit4;
+        }
+        /* circle ping-pong buffers */
+        edma_link(prtd->asp_link[0], prtd->asp_link[1]);
+        edma_link(prtd->asp_link[1], prtd->asp_link[0]);
+        /* circle ram buffers */
+        edma_link(prtd->ram_link, prtd->ram_link);
+
+        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                asp_src_ping = iram_dma->addr;
+                asp_dst_ping = params->dma_addr;        /* fifo */
+        } else {
+                asp_src_ping = params->dma_addr;        /* fifo */
+                asp_dst_ping = iram_dma->addr;
         }
+        /* ping */
+        link = prtd->asp_link[0];
+        edma_set_src(link, asp_src_ping, INCR, W16BIT);
+        edma_set_dest(link, asp_dst_ping, INCR, W16BIT);
+        edma_set_src_index(link, 0, 0);
+        edma_set_dest_index(link, 0, 0);
+
+        edma_read_slot(link, &prtd->asp_params);
+        prtd->asp_params.opt &= ~(TCCMODE | EDMA_TCC(0x3f) | TCINTEN);
+        prtd->asp_params.opt |= TCCHEN | EDMA_TCC(prtd->ram_channel & 0x3f);
+        edma_write_slot(link, &prtd->asp_params);
+
+        /* pong */
+        link = prtd->asp_link[1];
+        edma_set_src(link, asp_src_ping, INCR, W16BIT);
+        edma_set_dest(link, asp_dst_ping, INCR, W16BIT);
+        edma_set_src_index(link, 0, 0);
+        edma_set_dest_index(link, 0, 0);
+
+        edma_read_slot(link, &prtd->asp_params);
+        prtd->asp_params.opt &= ~(TCCMODE | EDMA_TCC(0x3f));
+        /* interrupt after every pong completion */
+        prtd->asp_params.opt |= TCINTEN | TCCHEN |
+                EDMA_TCC(EDMA_CHAN_SLOT(prtd->ram_channel));
+        edma_write_slot(link, &prtd->asp_params);
+
+        /* ram */
+        link = prtd->ram_link;
+        edma_set_src(link, iram_dma->addr, INCR, W32BIT);
+        edma_set_dest(link, iram_dma->addr, INCR, W32BIT);
+        pr_debug("%s: audio dma channels/slots in use for ram:%u %u %u,"
+                "for asp:%u %u %u\n", __func__,
+                prtd->ram_channel, prtd->ram_link, prtd->ram_link2,
+                prtd->asp_channel, prtd->asp_link[0],
+                prtd->asp_link[1]);
+        return 0;
+exit4:
+        edma_free_channel(prtd->asp_link[1]);
+        prtd->asp_link[1] = -1;
+exit3:
+        edma_free_channel(prtd->ram_link);
+        prtd->ram_link = -1;
+exit2:
+        edma_free_channel(prtd->ram_channel);
+        prtd->ram_channel = -1;
+exit1:
+        return link;
 }
 
 static int davinci_pcm_dma_request(struct snd_pcm_substream *substream)
 {
+        struct snd_dma_buffer *iram_dma;
         struct davinci_runtime_data *prtd = substream->runtime->private_data;
-        struct edmacc_param p_ram;
-        int ret;
+        struct davinci_pcm_dma_params *params = prtd->params;
+        int link;
 
-        /* Request master DMA channel */
-        ret = edma_alloc_channel(prtd->params->channel,
-                                  davinci_pcm_dma_irq, substream,
-                                  EVENTQ_0);
-        if (ret < 0)
-                return ret;
-        prtd->asp_channel = ret;
+        if (!params)
+                return -ENODEV;
 
-        /* Request parameter RAM reload slot */
-        ret = edma_alloc_slot(EDMA_CTLR(prtd->asp_channel), EDMA_SLOT_ANY);
-        if (ret < 0) {
-                edma_free_channel(prtd->asp_channel);
-                return ret;
+        /* Request asp master DMA channel */
+        link = prtd->asp_channel = edma_alloc_channel(params->channel,
+                        davinci_pcm_dma_irq, substream, EVENTQ_0);
+        if (link < 0)
+                goto exit1;
+
+        /* Request asp link channels */
+        link = prtd->asp_link[0] = edma_alloc_slot(
+                        EDMA_CTLR(prtd->asp_channel), EDMA_SLOT_ANY);
+        if (link < 0)
+                goto exit2;
+
+        iram_dma = (struct snd_dma_buffer *)substream->dma_buffer.private_data;
+        if (iram_dma) {
+                if (request_ping_pong(substream, prtd, iram_dma) == 0)
+                        return 0;
+                printk(KERN_WARNING "%s: dma channel allocation failed,"
+                                "not using sram\n", __func__);
         }
-        prtd->asp_link[0] = ret;
 
         /* Issue transfer completion IRQ when the channel completes a
          * transfer, then always reload from the same slot (by a kind
@@ -169,12 +504,17 @@ static int davinci_pcm_dma_request(struct snd_pcm_substream *substream)
          * the buffer and its length (ccnt) ... use it as a template
          * so davinci_pcm_enqueue_dma() takes less time in IRQ.
          */
-        edma_read_slot(prtd->asp_link[0], &p_ram);
-        p_ram.opt |= TCINTEN | EDMA_TCC(EDMA_CHAN_SLOT(prtd->asp_channel));
-        p_ram.link_bcntrld = EDMA_CHAN_SLOT(prtd->asp_link[0]) << 5;
-        edma_write_slot(prtd->asp_link[0], &p_ram);
-
+        edma_read_slot(link, &prtd->asp_params);
+        prtd->asp_params.opt |= TCINTEN |
+                EDMA_TCC(EDMA_CHAN_SLOT(prtd->asp_channel));
+        prtd->asp_params.link_bcntrld = EDMA_CHAN_SLOT(link) << 5;
+        edma_write_slot(link, &prtd->asp_params);
         return 0;
+exit2:
+        edma_free_channel(prtd->asp_channel);
+        prtd->asp_channel = -1;
+exit1:
+        return link;
 }
 
 static int davinci_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
@@ -208,14 +548,34 @@ static int davinci_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
 static int davinci_pcm_prepare(struct snd_pcm_substream *substream)
 {
         struct davinci_runtime_data *prtd = substream->runtime->private_data;
-        struct edmacc_param temp;
 
+        if (prtd->ram_channel >= 0) {
+                int ret = ping_pong_dma_setup(substream);
+                if (ret < 0)
+                        return ret;
+
+                edma_write_slot(prtd->ram_channel, &prtd->ram_params);
+                edma_write_slot(prtd->asp_channel, &prtd->asp_params);
+
+                print_buf_info(prtd->ram_channel, "ram_channel");
+                print_buf_info(prtd->ram_link, "ram_link");
+                print_buf_info(prtd->ram_link2, "ram_link2");
+                print_buf_info(prtd->asp_channel, "asp_channel");
+                print_buf_info(prtd->asp_link[0], "asp_link[0]");
+                print_buf_info(prtd->asp_link[1], "asp_link[1]");
+
+                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                        /* copy 1st iram buffer */
+                        edma_start(prtd->ram_channel);
+                }
+                return 0;
+        }
         prtd->period = 0;
         davinci_pcm_enqueue_dma(substream);
 
         /* Copy self-linked parameter RAM entry into master channel */
-        edma_read_slot(prtd->asp_link[0], &temp);
-        edma_write_slot(prtd->asp_channel, &temp);
+        edma_read_slot(prtd->asp_link[0], &prtd->asp_params);
+        edma_write_slot(prtd->asp_channel, &prtd->asp_params);
         davinci_pcm_enqueue_dma(substream);
 
         return 0;
@@ -231,13 +591,46 @@ davinci_pcm_pointer(struct snd_pcm_substream *substream)
         dma_addr_t asp_src, asp_dst;
 
         spin_lock(&prtd->lock);
-
-        edma_get_position(prtd->asp_channel, &asp_src, &asp_dst);
-        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
-                asp_count = asp_src - runtime->dma_addr;
-        else
-                asp_count = asp_dst - runtime->dma_addr;
-
+        if (prtd->ram_channel >= 0) {
+                int ram_count;
+                int mod_ram;
+                dma_addr_t ram_src, ram_dst;
+                unsigned int period_size = snd_pcm_lib_period_bytes(substream);
+                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                        /* reading ram before asp should be safe
+                         * as long as the asp transfers less than a ping size
+                         * of bytes between the 2 reads
+                         */
+                        edma_get_position(prtd->ram_channel,
+                                        &ram_src, &ram_dst);
+                        edma_get_position(prtd->asp_channel,
+                                        &asp_src, &asp_dst);
+                        asp_count = asp_src - prtd->asp_params.src;
+                        ram_count = ram_src - prtd->ram_params.src;
+                        mod_ram = ram_count % period_size;
+                        mod_ram -= asp_count;
+                        if (mod_ram < 0)
+                                mod_ram += period_size;
+                        else if (mod_ram == 0) {
+                                if (snd_pcm_running(substream))
+                                        mod_ram += period_size;
+                        }
+                        ram_count -= mod_ram;
+                        if (ram_count < 0)
+                                ram_count += period_size * runtime->periods;
+                } else {
+                        edma_get_position(prtd->ram_channel,
+                                        &ram_src, &ram_dst);
+                        ram_count = ram_dst - prtd->ram_params.dst;
+                }
+                asp_count = ram_count;
+        } else {
+                edma_get_position(prtd->asp_channel, &asp_src, &asp_dst);
+                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+                        asp_count = asp_src - runtime->dma_addr;
+                else
+                        asp_count = asp_dst - runtime->dma_addr;
+        }
         spin_unlock(&prtd->lock);
 
         offset = bytes_to_frames(runtime, asp_count);
@@ -251,6 +644,7 @@ static int davinci_pcm_open(struct snd_pcm_substream *substream)
 {
         struct snd_pcm_runtime *runtime = substream->runtime;
         struct davinci_runtime_data *prtd;
+        struct snd_pcm_hardware *ppcm;
         int ret = 0;
         struct snd_soc_pcm_runtime *rtd = substream->private_data;
         struct davinci_pcm_dma_params *pa = rtd->dai->cpu_dai->dma_data;
@@ -259,7 +653,10 @@ static int davinci_pcm_open(struct snd_pcm_substream *substream)
                 return -ENODEV;
         params = &pa[substream->stream];
 
-        snd_soc_set_runtime_hwparams(substream, &davinci_pcm_hardware);
+        ppcm = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
+                        &pcm_hardware_playback : &pcm_hardware_capture;
+        allocate_sram(substream, params->sram_size, ppcm);
+        snd_soc_set_runtime_hwparams(substream, ppcm);
         /* ensure that buffer size is a multiple of period size */
         ret = snd_pcm_hw_constraint_integer(runtime,
                                                 SNDRV_PCM_HW_PARAM_PERIODS);
@@ -272,6 +669,11 @@ static int davinci_pcm_open(struct snd_pcm_substream *substream)
 
         spin_lock_init(&prtd->lock);
         prtd->params = params;
+        prtd->asp_channel = -1;
+        prtd->asp_link[0] = prtd->asp_link[1] = -1;
+        prtd->ram_channel = -1;
+        prtd->ram_link = -1;
+        prtd->ram_link2 = -1;
 
         runtime->private_data = prtd;
 
@@ -289,10 +691,29 @@ static int davinci_pcm_close(struct snd_pcm_substream *substream)
         struct snd_pcm_runtime *runtime = substream->runtime;
         struct davinci_runtime_data *prtd = runtime->private_data;
 
-        edma_unlink(prtd->asp_link[0]);
-
-        edma_free_slot(prtd->asp_link[0]);
-        edma_free_channel(prtd->asp_channel);
+        if (prtd->ram_channel >= 0)
+                edma_stop(prtd->ram_channel);
+        if (prtd->asp_channel >= 0)
+                edma_stop(prtd->asp_channel);
+        if (prtd->asp_link[0] >= 0)
+                edma_unlink(prtd->asp_link[0]);
+        if (prtd->asp_link[1] >= 0)
+                edma_unlink(prtd->asp_link[1]);
+        if (prtd->ram_link >= 0)
+                edma_unlink(prtd->ram_link);
+
+        if (prtd->asp_link[0] >= 0)
+                edma_free_slot(prtd->asp_link[0]);
+        if (prtd->asp_link[1] >= 0)
+                edma_free_slot(prtd->asp_link[1]);
+        if (prtd->asp_channel >= 0)
+                edma_free_channel(prtd->asp_channel);
+        if (prtd->ram_link >= 0)
+                edma_free_slot(prtd->ram_link);
+        if (prtd->ram_link2 >= 0)
+                edma_free_slot(prtd->ram_link2);
+        if (prtd->ram_channel >= 0)
+                edma_free_channel(prtd->ram_channel);
 
         kfree(prtd);
 
@@ -334,11 +755,11 @@ static struct snd_pcm_ops davinci_pcm_ops = {
         .mmap =         davinci_pcm_mmap,
 };
 
-static int davinci_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
+static int davinci_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream,
+                size_t size)
 {
         struct snd_pcm_substream *substream = pcm->streams[stream].substream;
         struct snd_dma_buffer *buf = &substream->dma_buffer;
-        size_t size = davinci_pcm_hardware.buffer_bytes_max;
 
         buf->dev.type = SNDRV_DMA_TYPE_DEV;
         buf->dev.dev = pcm->card->dev;
@@ -363,6 +784,7 @@ static void davinci_pcm_free(struct snd_pcm *pcm)
         int stream;
 
         for (stream = 0; stream < 2; stream++) {
+                struct snd_dma_buffer *iram_dma;
                 substream = pcm->streams[stream].substream;
                 if (!substream)
                         continue;
@@ -374,6 +796,11 @@ static void davinci_pcm_free(struct snd_pcm *pcm)
                 dma_free_writecombine(pcm->card->dev, buf->bytes,
                                       buf->area, buf->addr);
                 buf->area = NULL;
+                iram_dma = (struct snd_dma_buffer *)buf->private_data;
+                if (iram_dma) {
+                        sram_free(iram_dma->area, iram_dma->bytes);
+                        kfree(iram_dma);
+                }
         }
 }
 
@@ -391,14 +818,16 @@ static int davinci_pcm_new(struct snd_card *card,
 
         if (dai->playback.channels_min) {
                 ret = davinci_pcm_preallocate_dma_buffer(pcm,
-                        SNDRV_PCM_STREAM_PLAYBACK);
+                        SNDRV_PCM_STREAM_PLAYBACK,
+                        pcm_hardware_playback.buffer_bytes_max);
                 if (ret)
                         return ret;
         }
 
         if (dai->capture.channels_min) {
                 ret = davinci_pcm_preallocate_dma_buffer(pcm,
-                        SNDRV_PCM_STREAM_CAPTURE);
+                        SNDRV_PCM_STREAM_CAPTURE,
+                        pcm_hardware_capture.buffer_bytes_max);
                 if (ret)
                         return ret;
         }
diff --git a/sound/soc/davinci/davinci-pcm.h b/sound/soc/davinci/davinci-pcm.h
index c8b0d2baf05a..0764944cf10f 100644
--- a/sound/soc/davinci/davinci-pcm.h
+++ b/sound/soc/davinci/davinci-pcm.h
@@ -20,6 +20,7 @@ struct davinci_pcm_dma_params {
         int channel;                    /* sync dma channel ID */
         unsigned short acnt;
         dma_addr_t dma_addr;            /* device physical address for DMA */
+        unsigned sram_size;
         enum dma_event_q eventq_no;     /* event queue number */
         unsigned char data_type;        /* xfer data type */
         unsigned char convert_mono_stereo;