[PATCH v2 2/2] dmaengine: hdmac: Add memset capabilities
Maxime Ripard
maxime.ripard at free-electrons.com
Mon Jul 20 01:42:58 PDT 2015
Just like for the XDMAC, the SoCs that embed the HDMAC don't have any kind
of GPU, and need to accelerate a few framebuffer-related operations through
their DMA controller.
However, unlike the XDMAC, the HDMAC doesn't have the memset capability
built-in. That can be easily emulated though, by doing a transfer with a
fixed adress on the variable that holds the value we want to set.
Signed-off-by: Maxime Ripard <maxime.ripard at free-electrons.com>
---
Changes from v1:
- Replaced the dma_alloc_coherent calls by a dma_pool
drivers/dma/at_hdmac.c | 124 ++++++++++++++++++++++++++++++++++++++++++--
drivers/dma/at_hdmac_regs.h | 6 +++
2 files changed, 127 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 59892126d175..44f4891b71ad 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -390,6 +390,7 @@ static void
atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
{
struct dma_async_tx_descriptor *txd = &desc->txd;
+ struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
dev_vdbg(chan2dev(&atchan->chan_common),
"descriptor %u complete\n", txd->cookie);
@@ -398,6 +399,13 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
if (!atc_chan_is_cyclic(atchan))
dma_cookie_complete(txd);
+ /* If the transfer was a memset, free our temporary buffer */
+ if (desc->memset) {
+ dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
+ desc->memset_paddr);
+ desc->memset = false;
+ }
+
/* move children to free_list */
list_splice_init(&desc->tx_list, &atchan->free_list);
/* move myself to free_list */
@@ -820,6 +828,96 @@ err_desc_get:
return NULL;
}
+/**
+ * atc_prep_dma_memset - prepare a memcpy operation
+ * @chan: the channel to prepare operation on
+ * @dest: operation virtual destination address
+ * @value: value to set memory buffer to
+ * @len: operation length
+ * @flags: tx descriptor status flags
+ */
+static struct dma_async_tx_descriptor *
+atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
+ size_t len, unsigned long flags)
+{
+ struct at_dma_chan *atchan = to_at_dma_chan(chan);
+ struct at_dma *atdma = to_at_dma(chan->device);
+ struct at_desc *desc = NULL;
+ size_t xfer_count;
+ u32 ctrla;
+ u32 ctrlb;
+
+ dev_vdbg(chan2dev(chan), "%s: d0x%x v0x%x l0x%zx f0x%lx\n", __func__,
+ dest, value, len, flags);
+
+ if (unlikely(!len)) {
+ dev_dbg(chan2dev(chan), "%s: length is zero!\n", __func__);
+ return NULL;
+ }
+
+ if (!is_dma_fill_aligned(chan->device, dest, 0, len)) {
+ dev_dbg(chan2dev(chan), "%s: buffer is not aligned\n",
+ __func__);
+ return NULL;
+ }
+
+ xfer_count = len >> 2;
+ if (xfer_count > ATC_BTSIZE_MAX) {
+ dev_err(chan2dev(chan), "%s: buffer is too big\n",
+ __func__);
+ return NULL;
+ }
+
+ ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN
+ | ATC_SRC_ADDR_MODE_FIXED
+ | ATC_DST_ADDR_MODE_INCR
+ | ATC_FC_MEM2MEM;
+
+ ctrla = ATC_SRC_WIDTH(2) |
+ ATC_DST_WIDTH(2);
+
+ desc = atc_desc_get(atchan);
+ if (!desc) {
+ dev_err(chan2dev(chan), "%s: can't get a descriptor\n",
+ __func__);
+ return NULL;
+ }
+
+ desc->memset_vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC,
+ &desc->memset_paddr);
+ if (!desc->memset_vaddr) {
+ dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
+ __func__);
+ goto err_put_desc;
+ }
+
+ *desc->memset_vaddr = value;
+ desc->memset = true;
+
+ desc->lli.saddr = desc->memset_paddr;
+ desc->lli.daddr = dest;
+ desc->lli.ctrla = ctrla | xfer_count;
+ desc->lli.ctrlb = ctrlb;
+
+ desc->txd.cookie = -EBUSY;
+ desc->len = len;
+ desc->total_len = len;
+
+ /* set transfer width for the calculation of the residue */
+ desc->tx_width = 2;
+
+ /* set end-of-link on the descriptor */
+ set_desc_eol(desc);
+
+ desc->txd.flags = flags;
+
+ return &desc->txd;
+
+err_put_desc:
+ atc_desc_put(atchan, desc);
+ return NULL;
+}
+
/**
* atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
@@ -1713,6 +1811,8 @@ static int __init at_dma_probe(struct platform_device *pdev)
dma_cap_set(DMA_SG, at91sam9rl_config.cap_mask);
dma_cap_set(DMA_INTERLEAVE, at91sam9g45_config.cap_mask);
dma_cap_set(DMA_MEMCPY, at91sam9g45_config.cap_mask);
+ dma_cap_set(DMA_MEMSET, at91sam9g45_config.cap_mask);
+ dma_cap_set(DMA_PRIVATE, at91sam9g45_config.cap_mask);
dma_cap_set(DMA_SLAVE, at91sam9g45_config.cap_mask);
dma_cap_set(DMA_SG, at91sam9g45_config.cap_mask);
@@ -1776,7 +1876,16 @@ static int __init at_dma_probe(struct platform_device *pdev)
if (!atdma->dma_desc_pool) {
dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
err = -ENOMEM;
- goto err_pool_create;
+ goto err_desc_pool_create;
+ }
+
+ /* create a pool of consistent memory blocks for memset blocks */
+ atdma->memset_pool = dma_pool_create("at_hdmac_memset_pool",
+ &pdev->dev, sizeof(int), 4, 0);
+ if (!atdma->memset_pool) {
+ dev_err(&pdev->dev, "No memory for memset dma pool\n");
+ err = -ENOMEM;
+ goto err_memset_pool_create;
}
/* clear any pending interrupt */
@@ -1822,6 +1931,11 @@ static int __init at_dma_probe(struct platform_device *pdev)
if (dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask))
atdma->dma_common.device_prep_dma_memcpy = atc_prep_dma_memcpy;
+ if (dma_has_cap(DMA_MEMSET, atdma->dma_common.cap_mask)) {
+ atdma->dma_common.device_prep_dma_memset = atc_prep_dma_memset;
+ atdma->dma_common.fill_align = DMAENGINE_ALIGN_4_BYTES;
+ }
+
if (dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask)) {
atdma->dma_common.device_prep_slave_sg = atc_prep_slave_sg;
/* controller can do slave DMA: can trigger cyclic transfers */
@@ -1842,8 +1956,9 @@ static int __init at_dma_probe(struct platform_device *pdev)
dma_writel(atdma, EN, AT_DMA_ENABLE);
- dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s%s), %d channels\n",
+ dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s%s%s), %d channels\n",
dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "",
+ dma_has_cap(DMA_MEMSET, atdma->dma_common.cap_mask) ? "set " : "",
dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "",
dma_has_cap(DMA_SG, atdma->dma_common.cap_mask) ? "sg-cpy " : "",
plat_dat->nr_channels);
@@ -1868,8 +1983,10 @@ static int __init at_dma_probe(struct platform_device *pdev)
err_of_dma_controller_register:
dma_async_device_unregister(&atdma->dma_common);
+ dma_pool_destroy(atdma->memset_pool);
+err_memset_pool_create:
dma_pool_destroy(atdma->dma_desc_pool);
-err_pool_create:
+err_desc_pool_create:
free_irq(platform_get_irq(pdev, 0), atdma);
err_irq:
clk_disable_unprepare(atdma->clk);
@@ -1894,6 +2011,7 @@ static int at_dma_remove(struct platform_device *pdev)
at_dma_off(atdma);
dma_async_device_unregister(&atdma->dma_common);
+ dma_pool_destroy(atdma->memset_pool);
dma_pool_destroy(atdma->dma_desc_pool);
free_irq(platform_get_irq(pdev, 0), atdma);
diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
index bc8d5ebedd19..a2283886dd87 100644
--- a/drivers/dma/at_hdmac_regs.h
+++ b/drivers/dma/at_hdmac_regs.h
@@ -201,6 +201,11 @@ struct at_desc {
size_t boundary;
size_t dst_hole;
size_t src_hole;
+
+ /* Memset temporary buffer */
+ bool memset;
+ dma_addr_t memset_paddr;
+ int *memset_vaddr;
};
static inline struct at_desc *
@@ -331,6 +336,7 @@ struct at_dma {
u8 all_chan_mask;
struct dma_pool *dma_desc_pool;
+ struct dma_pool *memset_pool;
/* AT THE END channels table */
struct at_dma_chan chan[0];
};
--
2.4.5
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