[PATCH V2 18/20] dmaengine/amba-pl08x: Add support for sg len greater than one for slave transfers

From: Viresh Kumar
Date: Mon Aug 01 2011 - 05:40:18 EST

Untill now, sg_len greater than one is not supported. This patch adds support to
do that.

Note: Still, if peripheral is flow controller, sg_len can't be greater that one.

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxx>
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
drivers/dma/amba-pl08x.c | 375 +++++++++++++++++++++++++-------------------
include/linux/amba/pl08x.h | 22 ++-
2 files changed, 229 insertions(+), 168 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index d573dc2..adc8a36 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -349,7 +349,9 @@ static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan)
if (!list_empty(&plchan->pend_list)) {
struct pl08x_txd *txdi;
list_for_each_entry(txdi, &plchan->pend_list, node) {
- bytes += txdi->len;
+ struct pl08x_sg *dsg;
+ list_for_each_entry(dsg, &txd->dsg_list, node)
+ bytes += dsg->len;
}
}

@@ -563,6 +565,7 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
u32 cctl, early_bytes = 0;
size_t max_bytes_per_lli, total_bytes = 0;
struct pl08x_lli *llis_va;
+ struct pl08x_sg *dsg;

txd->llis_va = dma_pool_alloc(pl08x->pool, GFP_NOWAIT, &txd->llis_bus);
if (!txd->llis_va) {
@@ -572,13 +575,9 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,

pl08x->pool_ctr++;

- /* Get the default CCTL */
- cctl = txd->cctl;
-
bd.txd = txd;
- bd.srcbus.addr = txd->src_addr;
- bd.dstbus.addr = txd->dst_addr;
bd.lli_bus = (pl08x->lli_buses & PL08X_AHB2) ? PL080_LLI_LM_AHB2 : 0;
+ cctl = txd->cctl;

/* Find maximum width of the source bus */
bd.srcbus.maxwidth =
@@ -590,162 +589,178 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
pl08x_get_bytes_for_cctl((cctl & PL080_CONTROL_DWIDTH_MASK) >>
PL080_CONTROL_DWIDTH_SHIFT);

- /* Set up the bus widths to the maximum */
- bd.srcbus.buswidth = bd.srcbus.maxwidth;
- bd.dstbus.buswidth = bd.dstbus.maxwidth;
+ list_for_each_entry(dsg, &txd->dsg_list, node) {
+ cctl = txd->cctl;

- /* We need to count this down to zero */
- bd.remainder = txd->len;
+ bd.srcbus.addr = dsg->src_addr;
+ bd.dstbus.addr = dsg->dst_addr;
+ bd.remainder = dsg->len;
+ bd.srcbus.buswidth = bd.srcbus.maxwidth;
+ bd.dstbus.buswidth = bd.dstbus.maxwidth;

- pl08x_choose_master_bus(&bd, &mbus, &sbus, cctl);
+ pl08x_choose_master_bus(&bd, &mbus, &sbus, cctl);

- dev_vdbg(&pl08x->adev->dev, "src=0x%08x%s/%u dst=0x%08x%s/%u len=%zu\n",
- bd.srcbus.addr, cctl & PL080_CONTROL_SRC_INCR ? "+" : "",
- bd.srcbus.buswidth,
- bd.dstbus.addr, cctl & PL080_CONTROL_DST_INCR ? "+" : "",
- bd.dstbus.buswidth,
- bd.remainder);
- dev_vdbg(&pl08x->adev->dev, "mbus=%s sbus=%s\n",
- mbus == &bd.srcbus ? "src" : "dst",
- sbus == &bd.srcbus ? "src" : "dst");
+ dev_vdbg(&pl08x->adev->dev, "src=0x%08x%s/%u dst=0x%08x%s/%u len=%zu\n",
+ bd.srcbus.addr, cctl & PL080_CONTROL_SRC_INCR ? "+" : "",
+ bd.srcbus.buswidth,
+ bd.dstbus.addr, cctl & PL080_CONTROL_DST_INCR ? "+" : "",
+ bd.dstbus.buswidth,
+ bd.remainder);
+ dev_vdbg(&pl08x->adev->dev, "mbus=%s sbus=%s\n",
+ mbus == &bd.srcbus ? "src" : "dst",
+ sbus == &bd.srcbus ? "src" : "dst");

- /*
- * Zero length is only allowed if all these requirements are met:
- * - flow controller is peripheral.
- * - src.addr is aligned to src.width
- * - dst.addr is aligned to dst.width
- *
- * sg_len == 1 should be true, as there can be two cases here:
- * - Memory addresses are contiguous and are not scattered. Here, Only
- * one sg will be passed by user driver, with memory address and zero
- * length. We pass this to controller and after the transfer it will
- * receive the last burst request from peripheral and so transfer
- * finishes.
- *
- * - Memory addresses are scattered and are not contiguous. Here,
- * Obviously as DMA controller doesn't know when a lli's transfer gets
- * over, it can't load next lli. So in this case, there has to be an
- * assumption that only one lli is supported. Thus, we can't have
- * scattered addresses.
- */
- if (!bd.remainder) {
- u32 fc = (txd->ccfg & PL080_CONFIG_FLOW_CONTROL_MASK) >>
- PL080_CONFIG_FLOW_CONTROL_SHIFT;
- if (!((fc >= PL080_FLOW_SRC2DST_DST) &&
+ /*
+ * Zero length is only allowed if all these requirements are
+ * met:
+ * - flow controller is peripheral.
+ * - src.addr is aligned to src.width
+ * - dst.addr is aligned to dst.width
+ *
+ * sg_len == 1 should be true, as there can be two cases here:
+ *
+ * - Memory addresses are contiguous and are not scattered.
+ * Here, Only one sg will be passed by user driver, with
+ * memory address and zero length. We pass this to controller
+ * and after the transfer it will receive the last burst
+ * request from peripheral and so transfer finishes.
+ *
+ * - Memory addresses are scattered and are not contiguous.
+ * Here, Obviously as DMA controller doesn't know when a lli's
+ * transfer gets over, it can't load next lli. So in this
+ * case, there has to be an assumption that only one lli is
+ * supported. Thus, we can't have scattered addresses.
+ */
+ if (!bd.remainder) {
+ u32 fc = (txd->ccfg & PL080_CONFIG_FLOW_CONTROL_MASK) >>
+ PL080_CONFIG_FLOW_CONTROL_SHIFT;
+ if (!((fc >= PL080_FLOW_SRC2DST_DST) &&
(fc <= PL080_FLOW_SRC2DST_SRC))) {
- dev_err(&pl08x->adev->dev, "%s sg len can't be zero",
- __func__);
- return 0;
- }
-
- if ((bd.srcbus.addr % bd.srcbus.buswidth) ||
- (bd.srcbus.addr % bd.srcbus.buswidth)) {
- dev_err(&pl08x->adev->dev,
- "%s src & dst address must be aligned to src"
- " & dst width if peripheral is flow controller",
- __func__);
- return 0;
- }
-
- cctl = pl08x_cctl_bits(cctl, bd.srcbus.buswidth,
- bd.dstbus.buswidth, 0);
- pl08x_fill_lli_for_desc(&bd, num_llis++, 0, cctl);
- }
+ dev_err(&pl08x->adev->dev, "%s sg len can't be zero",
+ __func__);
+ return 0;
+ }

- /*
- * Send byte by byte for following cases
- * - Less than a bus width available
- * - until master bus is aligned
- */
- if (bd.remainder < mbus->buswidth)
- early_bytes = bd.remainder;
- else if ((mbus->addr) % (mbus->buswidth)) {
- early_bytes = mbus->buswidth - (mbus->addr) % (mbus->buswidth);
- if ((bd.remainder - early_bytes) < mbus->buswidth)
- early_bytes = bd.remainder;
- }
+ if ((bd.srcbus.addr % bd.srcbus.buswidth) ||
+ (bd.srcbus.addr % bd.srcbus.buswidth)) {
+ dev_err(&pl08x->adev->dev,
+ "%s src & dst address must be aligned to src"
+ " & dst width if peripheral is flow controller",
+ __func__);
+ return 0;
+ }

- if (early_bytes) {
- dev_vdbg(&pl08x->adev->dev, "%s byte width LLIs "
- "(remain 0x%08x)\n", __func__, bd.remainder);
- prep_byte_width_lli(&bd, &cctl, early_bytes, num_llis++,
- &total_bytes);
- }
+ cctl = pl08x_cctl_bits(cctl, bd.srcbus.buswidth,
+ bd.dstbus.buswidth, 0);
+ pl08x_fill_lli_for_desc(&bd, num_llis++, 0, cctl);
+ break;
+ }

- if (bd.remainder) {
/*
- * Master now aligned
- * - if slave is not then we must set its width down
+ * Send byte by byte for following cases
+ * - Less than a bus width available
+ * - until master bus is aligned
*/
- if (sbus->addr % sbus->buswidth) {
- dev_dbg(&pl08x->adev->dev,
- "%s set down bus width to one byte\n",
- __func__);
+ if (bd.remainder < mbus->buswidth)
+ early_bytes = bd.remainder;
+ else if ((mbus->addr) % (mbus->buswidth)) {
+ early_bytes = mbus->buswidth - (mbus->addr) %
+ (mbus->buswidth);
+ if ((bd.remainder - early_bytes) < mbus->buswidth)
+ early_bytes = bd.remainder;
+ }

- sbus->buswidth = 1;
+ if (early_bytes) {
+ dev_vdbg(&pl08x->adev->dev,
+ "%s byte width LLIs (remain 0x%08x)\n",
+ __func__, bd.remainder);
+ prep_byte_width_lli(&bd, &cctl, early_bytes, num_llis++,
+ &total_bytes);
}

- /* Bytes transferred = tsize * src width, not MIN(buswidths) */
- max_bytes_per_lli = bd.srcbus.buswidth *
- PL080_CONTROL_TRANSFER_SIZE_MASK;
+ if (bd.remainder) {
+ /*
+ * Master now aligned
+ * - if slave is not then we must set its width down
+ */
+ if (sbus->addr % sbus->buswidth) {
+ dev_dbg(&pl08x->adev->dev,
+ "%s set down bus width to one byte\n",
+ __func__);

- /*
- * Make largest possible LLIs until less than one bus
- * width left
- */
- while (bd.remainder > (mbus->buswidth - 1)) {
- size_t lli_len, tsize, width;
+ sbus->buswidth = 1;
+ }

/*
- * If enough left try to send max possible,
- * otherwise try to send the remainder
+ * Bytes transferred = tsize * src width, not
+ * MIN(buswidths)
*/
- lli_len = min(bd.remainder, max_bytes_per_lli);
+ max_bytes_per_lli = bd.srcbus.buswidth *
+ PL080_CONTROL_TRANSFER_SIZE_MASK;
+ dev_vdbg(&pl08x->adev->dev,
+ "%s max bytes per lli = %zu\n",
+ __func__, max_bytes_per_lli);

/*
- * Check against maximum bus alignment: Calculate actual
- * transfer size in relation to bus width and get a
- * maximum remainder of the highest bus width - 1
+ * Make largest possible LLIs until less than one bus
+ * width left
*/
- width = max(mbus->buswidth, sbus->buswidth);
- lli_len = (lli_len / width) * width;
- tsize = lli_len / bd.srcbus.buswidth;
+ while (bd.remainder > (mbus->buswidth - 1)) {
+ size_t lli_len, tsize, width;

- dev_vdbg(&pl08x->adev->dev,
- "%s fill lli with single lli chunk of "
- "size 0x%08zx (remainder 0x%08zx)\n",
- __func__, lli_len, bd.remainder);
+ /*
+ * If enough left try to send max possible,
+ * otherwise try to send the remainder
+ */
+ lli_len = min(bd.remainder, max_bytes_per_lli);

- cctl = pl08x_cctl_bits(cctl, bd.srcbus.buswidth,
+ /*
+ * Check against maximum bus alignment:
+ * Calculate actual transfer size in relation to
+ * bus width an get a maximum remainder of the
+ * highest bus width - 1
+ */
+ width = max(mbus->buswidth, sbus->buswidth);
+ lli_len = (lli_len / width) * width;
+ tsize = lli_len / bd.srcbus.buswidth;
+
+ dev_vdbg(&pl08x->adev->dev,
+ "%s fill lli with single lli chunk of "
+ "size 0x%08zx (remainder 0x%08zx)\n",
+ __func__, lli_len, bd.remainder);
+
+ cctl = pl08x_cctl_bits(cctl, bd.srcbus.buswidth,
bd.dstbus.buswidth, tsize);
- pl08x_fill_lli_for_desc(&bd, num_llis++, lli_len, cctl);
- total_bytes += lli_len;
- }
+ pl08x_fill_lli_for_desc(&bd, num_llis++,
+ lli_len, cctl);
+ total_bytes += lli_len;
+ }

- /*
- * Send any odd bytes
- */
- if (bd.remainder) {
- dev_vdbg(&pl08x->adev->dev,
- "%s align with boundary, send odd bytes (remain %zu)\n",
- __func__, bd.remainder);
- prep_byte_width_lli(&bd, &cctl, bd.remainder,
- num_llis++, &total_bytes);
+ /*
+ * Send any odd bytes
+ */
+ if (bd.remainder) {
+ dev_vdbg(&pl08x->adev->dev,
+ "%s align with boundary, send odd bytes (remain %zu)\n",
+ __func__, bd.remainder);
+ prep_byte_width_lli(&bd, &cctl, bd.remainder,
+ num_llis++, &total_bytes);
+ }
}
- }

- if (total_bytes != txd->len) {
- dev_err(&pl08x->adev->dev,
- "%s size of encoded lli:s don't match total txd, transferred 0x%08zx from size 0x%08zx\n",
- __func__, total_bytes, txd->len);
- return 0;
- }
+ if (total_bytes != dsg->len) {
+ dev_err(&pl08x->adev->dev,
+ "%s size of encoded lli:s don't match total txd, transferred 0x%08zx from size 0x%08zx\n",
+ __func__, total_bytes, dsg->len);
+ return 0;
+ }

- if (num_llis >= MAX_NUM_TSFR_LLIS) {
- dev_err(&pl08x->adev->dev,
- "%s need to increase MAX_NUM_TSFR_LLIS from 0x%08x\n",
- __func__, (u32) MAX_NUM_TSFR_LLIS);
- return 0;
+ if (num_llis >= MAX_NUM_TSFR_LLIS) {
+ dev_err(&pl08x->adev->dev,
+ "%s need to increase MAX_NUM_TSFR_LLIS from 0x%08x\n",
+ __func__, (u32) MAX_NUM_TSFR_LLIS);
+ return 0;
+ }
}

llis_va = txd->llis_va;
@@ -778,11 +793,18 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
static void pl08x_free_txd(struct pl08x_driver_data *pl08x,
struct pl08x_txd *txd)
{
+ struct pl08x_sg *dsg, *_dsg;
+
/* Free the LLI */
dma_pool_free(pl08x->pool, txd->llis_va, txd->llis_bus);

pl08x->pool_ctr--;

+ list_for_each_entry_safe(dsg, _dsg, &txd->dsg_list, node) {
+ list_del(&dsg->node);
+ kfree(dsg);
+ }
+
kfree(txd);
}

@@ -1234,6 +1256,7 @@ static struct pl08x_txd *pl08x_get_txd(struct pl08x_dma_chan *plchan,
txd->tx.flags = flags;
txd->tx.tx_submit = pl08x_tx_submit;
INIT_LIST_HEAD(&txd->node);
+ INIT_LIST_HEAD(&txd->dsg_list);

/* Always enable error and terminal interrupts */
txd->ccfg = PL080_CONFIG_ERR_IRQ_MASK |
@@ -1252,6 +1275,7 @@ static struct dma_async_tx_descriptor *pl08x_prep_dma_memcpy(
struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
struct pl08x_driver_data *pl08x = plchan->host;
struct pl08x_txd *txd;
+ struct pl08x_sg *dsg;
int ret;

txd = pl08x_get_txd(plchan, flags);
@@ -1261,10 +1285,19 @@ static struct dma_async_tx_descriptor *pl08x_prep_dma_memcpy(
return NULL;
}

+ dsg = kzalloc(sizeof(struct pl08x_sg), GFP_NOWAIT);
+ if (!dsg) {
+ pl08x_free_txd(pl08x, txd);
+ dev_err(&pl08x->adev->dev, "%s no memory for pl080 sg\n",
+ __func__);
+ return NULL;
+ }
+ list_add_tail(&dsg->node, &txd->dsg_list);
+
txd->direction = DMA_NONE;
- txd->src_addr = src;
- txd->dst_addr = dest;
- txd->len = len;
+ dsg->src_addr = src;
+ dsg->dst_addr = dest;
+ dsg->len = len;

/* Set platform data for m2m */
txd->ccfg |= PL080_FLOW_MEM2MEM << PL080_CONFIG_FLOW_CONTROL_SHIFT;
@@ -1293,19 +1326,13 @@ static struct dma_async_tx_descriptor *pl08x_prep_slave_sg(
struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
struct pl08x_driver_data *pl08x = plchan->host;
struct pl08x_txd *txd;
+ struct pl08x_sg *dsg;
+ struct scatterlist *sg;
+ dma_addr_t slave_addr;
int ret, tmp;

- /*
- * Current implementation ASSUMES only one sg
- */
- if (sg_len != 1) {
- dev_err(&pl08x->adev->dev, "%s prepared too long sglist\n",
- __func__);
- BUG();
- }
-
dev_dbg(&pl08x->adev->dev, "%s prepare transaction of %d bytes from %s\n",
- __func__, sgl->length, plchan->name);
+ __func__, sgl->length, plchan->name);

txd = pl08x_get_txd(plchan, flags);
if (!txd) {
@@ -1324,17 +1351,15 @@ static struct dma_async_tx_descriptor *pl08x_prep_slave_sg(
* channel target address dynamically at runtime.
*/
txd->direction = direction;
- txd->len = sgl->length;

if (direction == DMA_TO_DEVICE) {
txd->cctl = plchan->dst_cctl;
- txd->src_addr = sgl->dma_address;
- txd->dst_addr = plchan->dst_addr;
+ slave_addr = plchan->dst_addr;
} else if (direction == DMA_FROM_DEVICE) {
txd->cctl = plchan->src_cctl;
- txd->src_addr = plchan->src_addr;
- txd->dst_addr = sgl->dma_address;
+ slave_addr = plchan->src_addr;
} else {
+ pl08x_free_txd(pl08x, txd);
dev_err(&pl08x->adev->dev,
"%s direction unsupported\n", __func__);
return NULL;
@@ -1349,6 +1374,26 @@ static struct dma_async_tx_descriptor *pl08x_prep_slave_sg(

txd->ccfg |= tmp << PL080_CONFIG_FLOW_CONTROL_SHIFT;

+ for_each_sg(sgl, sg, sg_len, tmp) {
+ dsg = kzalloc(sizeof(struct pl08x_sg), GFP_NOWAIT);
+ if (!dsg) {
+ pl08x_free_txd(pl08x, txd);
+ dev_err(&pl08x->adev->dev, "%s no mem for pl080 sg\n",
+ __func__);
+ return NULL;
+ }
+ list_add_tail(&dsg->node, &txd->dsg_list);
+
+ dsg->len = sg_dma_len(sg);
+ if (direction == DMA_TO_DEVICE) {
+ dsg->src_addr = sg_phys(sg);
+ dsg->dst_addr = slave_addr;
+ } else {
+ dsg->src_addr = slave_addr;
+ dsg->dst_addr = sg_phys(sg);
+ }
+ }
+
ret = pl08x_prep_channel_resources(plchan, txd);
if (ret)
return NULL;
@@ -1446,22 +1491,28 @@ static void pl08x_ensure_on(struct pl08x_driver_data *pl08x)
static void pl08x_unmap_buffers(struct pl08x_txd *txd)
{
struct device *dev = txd->tx.chan->device->dev;
+ struct pl08x_sg *dsg;

if (!(txd->tx.flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
if (txd->tx.flags & DMA_COMPL_SRC_UNMAP_SINGLE)
- dma_unmap_single(dev, txd->src_addr, txd->len,
- DMA_TO_DEVICE);
- else
- dma_unmap_page(dev, txd->src_addr, txd->len,
- DMA_TO_DEVICE);
+ list_for_each_entry(dsg, &txd->dsg_list, node)
+ dma_unmap_single(dev, dsg->src_addr, dsg->len,
+ DMA_TO_DEVICE);
+ else {
+ list_for_each_entry(dsg, &txd->dsg_list, node)
+ dma_unmap_page(dev, dsg->src_addr, dsg->len,
+ DMA_TO_DEVICE);
+ }
}
if (!(txd->tx.flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
if (txd->tx.flags & DMA_COMPL_DEST_UNMAP_SINGLE)
- dma_unmap_single(dev, txd->dst_addr, txd->len,
- DMA_FROM_DEVICE);
+ list_for_each_entry(dsg, &txd->dsg_list, node)
+ dma_unmap_single(dev, dsg->dst_addr, dsg->len,
+ DMA_FROM_DEVICE);
else
- dma_unmap_page(dev, txd->dst_addr, txd->len,
- DMA_FROM_DEVICE);
+ list_for_each_entry(dsg, &txd->dsg_list, node)
+ dma_unmap_page(dev, dsg->dst_addr, dsg->len,
+ DMA_FROM_DEVICE);
}
}

diff --git a/include/linux/amba/pl08x.h b/include/linux/amba/pl08x.h
index a22662c..9eabffb 100644
--- a/include/linux/amba/pl08x.h
+++ b/include/linux/amba/pl08x.h
@@ -106,12 +106,24 @@ struct pl08x_phy_chan {
};

/**
+ * struct pl08x_sg - structure containing data per sg
+ * @src_addr: src address of sg
+ * @dst_addr: dst address of sg
+ * @len: transfer len in bytes
+ * @node: node for txd's dsg_list
+ */
+struct pl08x_sg {
+ dma_addr_t src_addr;
+ dma_addr_t dst_addr;
+ size_t len;
+ struct list_head node;
+};
+
+/**
* struct pl08x_txd - wrapper for struct dma_async_tx_descriptor
* @tx: async tx descriptor
* @node: node for txd list for channels
- * @src_addr: src address of txd
- * @dst_addr: dst address of txd
- * @len: transfer len in bytes
+ * @dsg_list: list of children sg's
* @direction: direction of transfer
* @llis_bus: DMA memory address (physical) start for the LLIs
* @llis_va: virtual memory address start for the LLIs
@@ -121,10 +133,8 @@ struct pl08x_phy_chan {
struct pl08x_txd {
struct dma_async_tx_descriptor tx;
struct list_head node;
+ struct list_head dsg_list;
enum dma_data_direction direction;
- dma_addr_t src_addr;
- dma_addr_t dst_addr;
- size_t len;
dma_addr_t llis_bus;
struct pl08x_lli *llis_va;
/* Default cctl value for LLIs */
--
1.7.2.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/