[PATCH v2 1/2] dmaengine: hdmac: factorise memset descriptor allocation

From: Maxime Ripard
Date: Thu Oct 22 2015 - 05:41:16 EST


The memset and scatter gathered memset are going to use some common logic
to create their descriptors.

Move that logic into a function of its own so that we can share it with the
future memset_sg callback.

Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
---
drivers/dma/at_hdmac.c | 97 ++++++++++++++++++++++++++-------------------
drivers/dma/at_hdmac_regs.h | 2 +-
2 files changed, 58 insertions(+), 41 deletions(-)

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 58d406230d89..cad18f3660ae 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -458,10 +458,10 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
dma_cookie_complete(txd);

/* If the transfer was a memset, free our temporary buffer */
- if (desc->memset) {
+ if (desc->memset_buffer) {
dma_pool_free(atdma->memset_pool, desc->memset_vaddr,
desc->memset_paddr);
- desc->memset = false;
+ desc->memset_buffer = false;
}

/* move children to free_list */
@@ -881,6 +881,46 @@ err_desc_get:
return NULL;
}

+static struct at_desc *atc_create_memset_desc(struct dma_chan *chan,
+ dma_addr_t psrc,
+ dma_addr_t pdst,
+ size_t len)
+{
+ struct at_dma_chan *atchan = to_at_dma_chan(chan);
+ struct at_desc *desc;
+ size_t xfer_count;
+
+ u32 ctrla = ATC_SRC_WIDTH(2) | ATC_DST_WIDTH(2);
+ u32 ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN |
+ ATC_SRC_ADDR_MODE_FIXED |
+ ATC_DST_ADDR_MODE_INCR |
+ ATC_FC_MEM2MEM;
+
+ xfer_count = len >> 2;
+ if (xfer_count > ATC_BTSIZE_MAX) {
+ dev_err(chan2dev(chan), "%s: buffer is too big\n",
+ __func__);
+ return NULL;
+ }
+
+ desc = atc_desc_get(atchan);
+ if (!desc) {
+ dev_err(chan2dev(chan), "%s: can't get a descriptor\n",
+ __func__);
+ return NULL;
+ }
+
+ desc->lli.saddr = psrc;
+ desc->lli.daddr = pdst;
+ desc->lli.ctrla = ctrla | xfer_count;
+ desc->lli.ctrlb = ctrlb;
+
+ desc->txd.cookie = 0;
+ desc->len = len;
+
+ return desc;
+}
+
/**
* atc_prep_dma_memset - prepare a memcpy operation
* @chan: the channel to prepare operation on
@@ -893,12 +933,10 @@ 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;
+ struct at_desc *desc;
+ void __iomem *vaddr;
+ dma_addr_t paddr;

dev_vdbg(chan2dev(chan), "%s: d0x%x v0x%x l0x%zx f0x%lx\n", __func__,
dest, value, len, flags);
@@ -914,46 +952,26 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
return NULL;
}

- xfer_count = len >> 2;
- if (xfer_count > ATC_BTSIZE_MAX) {
- dev_err(chan2dev(chan), "%s: buffer is too big\n",
+ vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
+ if (!vaddr) {
+ dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
__func__);
return NULL;
}
+ *(u32*)vaddr = value;

- 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);
+ desc = atc_create_memset_desc(chan, paddr, dest, len);
if (!desc) {
- dev_err(chan2dev(chan), "%s: can't get a descriptor\n",
+ dev_err(chan2dev(chan), "%s: couldn't get a descriptor\n",
__func__);
- return NULL;
+ goto err_free_buffer;
}

- 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->memset_paddr = paddr;
+ desc->memset_vaddr = vaddr;
+ desc->memset_buffer = true;

desc->txd.cookie = -EBUSY;
- desc->len = len;
desc->total_len = len;

/* set end-of-link on the descriptor */
@@ -963,12 +981,11 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,

return &desc->txd;

-err_put_desc:
- atc_desc_put(atchan, desc);
+err_free_buffer:
+ dma_pool_free(atdma->memset_pool, vaddr, paddr);
return NULL;
}

-
/**
* atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
* @chan: DMA channel
diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
index c3bebbe899ac..d1cfc8c876f9 100644
--- a/drivers/dma/at_hdmac_regs.h
+++ b/drivers/dma/at_hdmac_regs.h
@@ -202,7 +202,7 @@ struct at_desc {
size_t src_hole;

/* Memset temporary buffer */
- bool memset;
+ bool memset_buffer;
dma_addr_t memset_paddr;
int *memset_vaddr;
};
--
2.6.2

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