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authorSiva Yerramreddy <yshivakrishna@gmail.com>2015-09-30 03:09:37 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-10-04 13:46:06 +0200
commitff39988abd70bcd1b14a4c81f2d102e67b8db580 (patch)
treea51169c4006d757558c9415103d93440d0e8cd8f /drivers/dma
parentiommu: Allow iova to be used without requiring IOMMU_SUPPORT (diff)
downloadlinux-ff39988abd70bcd1b14a4c81f2d102e67b8db580.tar.xz
linux-ff39988abd70bcd1b14a4c81f2d102e67b8db580.zip
dma: Add support to program MIC x100 status descriptiors
The MIC X100 DMA engine has a special status descriptor which writes an 8 byte value to a destination location. This is used to signal completion of all DMA descriptors prior to the status descriptor. This patch add a new DMA engine API which enables updating a destination address with an 8 byte immediate data value. Reviewed-by: Nikhil Rao <nikhil.rao@intel.com> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Signed-off-by: Lawrynowicz, Jacek <jacek.lawrynowicz@intel.com> Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com> Signed-off-by: Siva Yerramreddy <yshivakrishna@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/mic_x100_dma.c39
1 files changed, 38 insertions, 1 deletions
diff --git a/drivers/dma/mic_x100_dma.c b/drivers/dma/mic_x100_dma.c
index 74d9db05a5ad..068e920ecb68 100644
--- a/drivers/dma/mic_x100_dma.c
+++ b/drivers/dma/mic_x100_dma.c
@@ -193,8 +193,16 @@ static void mic_dma_prog_intr(struct mic_dma_chan *ch)
static int mic_dma_do_dma(struct mic_dma_chan *ch, int flags, dma_addr_t src,
dma_addr_t dst, size_t len)
{
- if (-ENOMEM == mic_dma_prog_memcpy_desc(ch, src, dst, len))
+ if (len && -ENOMEM == mic_dma_prog_memcpy_desc(ch, src, dst, len)) {
return -ENOMEM;
+ } else {
+ /* 3 is the maximum number of status descriptors */
+ int ret = mic_dma_avail_desc_ring_space(ch, 3);
+
+ if (ret < 0)
+ return ret;
+ }
+
/* Above mic_dma_prog_memcpy_desc() makes sure we have enough space */
if (flags & DMA_PREP_FENCE) {
mic_dma_prep_status_desc(&ch->desc_ring[ch->head], 0,
@@ -270,6 +278,33 @@ allocate_tx(struct mic_dma_chan *ch)
return tx;
}
+/* Program a status descriptor with dst as address and value to be written */
+static struct dma_async_tx_descriptor *
+mic_dma_prep_status_lock(struct dma_chan *ch, dma_addr_t dst, u64 src_val,
+ unsigned long flags)
+{
+ struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
+ int result;
+
+ spin_lock(&mic_ch->prep_lock);
+ result = mic_dma_avail_desc_ring_space(mic_ch, 4);
+ if (result < 0)
+ goto error;
+ mic_dma_prep_status_desc(&mic_ch->desc_ring[mic_ch->head], src_val, dst,
+ false);
+ mic_dma_hw_ring_inc_head(mic_ch);
+ result = mic_dma_do_dma(mic_ch, flags, 0, 0, 0);
+ if (result < 0)
+ goto error;
+
+ return allocate_tx(mic_ch);
+error:
+ dev_err(mic_dma_ch_to_device(mic_ch),
+ "Error enqueueing dma status descriptor, error=%d\n", result);
+ spin_unlock(&mic_ch->prep_lock);
+ return NULL;
+}
+
/*
* Prepare a memcpy descriptor to be added to the ring.
* Note that the temporary descriptor adds an extra overhead of copying the
@@ -587,6 +622,8 @@ static int mic_dma_register_dma_device(struct mic_dma_device *mic_dma_dev,
mic_dma_free_chan_resources;
mic_dma_dev->dma_dev.device_tx_status = mic_dma_tx_status;
mic_dma_dev->dma_dev.device_prep_dma_memcpy = mic_dma_prep_memcpy_lock;
+ mic_dma_dev->dma_dev.device_prep_dma_imm_data =
+ mic_dma_prep_status_lock;
mic_dma_dev->dma_dev.device_prep_dma_interrupt =
mic_dma_prep_interrupt_lock;
mic_dma_dev->dma_dev.device_issue_pending = mic_dma_issue_pending;