Re: [PATCH] PCI: endpoint: functions/pci-epf-test: Support slave DMA transfer

Rob Herring
2020-05-07T21:45:07Z

On Fri, May 01, 2020 at 05:29:12PM -0700, Alan Mikhak wrote:
> From: Alan Mikhak <alan.mikhak@sifive.com>
>
> Modify pci_epf_test_data_transfer() to also support slave DMA transfers.
> Adds a direction parameter so caller can specify one of the supported DMA
> transfer directions: DMA_MEM_TO_MEM, DMA_MEM_TO_DEV, and DMA_DEV_TO_MEM.
> For DMA_MEM_TO_MEM, the function calls dmaengine_prep_dma_memcpy() as it
> did before. For DMA_MEM_TO_DEV or DMA_DEV_TO_MEM direction, the function
> calls dmaengine_slave_config() to configure the slave channel before it
> calls dmaengine_prep_slave_single().
>
> Modify existing callers to specify DMA_MEM_TO_MEM since that is the only
> possible option so far. Rename the phys_addr local variable in some of the
> callers for more readability. Tighten some of the timing function calls to
> avoid counting error print time in case of error.

Looks fine, but also needs a user. The last sentence sounds like a
separate change.

>
> Signed-off-by: Alan Mikhak <alan.mikhak@sifive.com>
> ---
> drivers/pci/endpoint/functions/pci-epf-test.c | 67 ++++++++++++++++++---------
> 1 file changed, 44 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 60330f3e3751..1d026682febb 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -104,25 +104,41 @@ static void pci_epf_test_dma_callback(void *param)
> * The function returns '0' on success and negative value on failure.
> */
> static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test,
> - dma_addr_t dma_dst, dma_addr_t dma_src,
> - size_t len)
> + dma_addr_t dma_dst,
> + dma_addr_t dma_src,
> + size_t len,
> + enum dma_transfer_direction dir)
> {
> enum dma_ctrl_flags flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
> struct dma_chan *chan = epf_test->dma_chan;
> struct pci_epf *epf = epf_test->epf;
> + struct dma_slave_config sconf;
> struct dma_async_tx_descriptor *tx;
> struct device *dev = &epf->dev;
> dma_cookie_t cookie;
> + dma_addr_t buf;
> int ret;
>
> if (IS_ERR_OR_NULL(chan)) {
> - dev_err(dev, "Invalid DMA memcpy channel\n");
> + dev_err(dev, "Invalid DMA channel\n");
> return -EINVAL;
> }
>
> - tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags);
> + if (dir == DMA_MEM_TO_MEM) {
> + tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src,
> + len, flags);
> + } else {
> + memset(&sconf, 0, sizeof(sconf));
> + sconf.direction = dir;
> + sconf.dst_addr = dma_dst;
> + sconf.src_addr = dma_src;
> + dmaengine_slave_config(chan, &sconf);
> +
> + buf = (dir == DMA_MEM_TO_DEV) ? dma_dst : dma_src;
> + tx = dmaengine_prep_slave_single(chan, buf, len, dir, flags);
> + }
> if (!tx) {
> - dev_err(dev, "Failed to prepare DMA memcpy\n");
> + dev_err(dev, "Failed to prepare DMA transfer\n");
> return -EIO;
> }
>
> @@ -268,7 +284,6 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> goto err_dst_addr;
> }
>
> - ktime_get_ts64(&start);
> use_dma = !!(reg->flags & FLAG_USE_DMA);
> if (use_dma) {
> if (!epf_test->dma_supported) {
> @@ -277,14 +292,18 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
> goto err_map_addr;
> }
>
> + ktime_get_ts64(&start);
> ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
> - src_phys_addr, reg->size);
> + src_phys_addr, reg->size,
> + DMA_MEM_TO_MEM);
> + ktime_get_ts64(&end);
> if (ret)
> dev_err(dev, "Data transfer failed\n");
> } else {
> + ktime_get_ts64(&start);
> memcpy(dst_addr, src_addr, reg->size);
> + ktime_get_ts64(&end);
> }
> - ktime_get_ts64(&end);
> pci_epf_test_print_rate("COPY", reg->size, &start, &end, use_dma);
>
> err_map_addr:
> @@ -310,7 +329,7 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> void *buf;
> u32 crc32;
> bool use_dma;
> - phys_addr_t phys_addr;
> + phys_addr_t src_phys_addr;
> phys_addr_t dst_phys_addr;
> struct timespec64 start, end;
> struct pci_epf *epf = epf_test->epf;
> @@ -319,8 +338,9 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> struct device *dma_dev = epf->epc->dev.parent;
> enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> + enum dma_transfer_direction dir = DMA_MEM_TO_MEM;
>
> - src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> + src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
> if (!src_addr) {
> dev_err(dev, "Failed to allocate address\n");
> reg->status = STATUS_SRC_ADDR_INVALID;
> @@ -328,7 +348,7 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> goto err;
> }
>
> - ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->src_addr,
> + ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, reg->src_addr,
> reg->size);
> if (ret) {
> dev_err(dev, "Failed to map address\n");
> @@ -360,10 +380,10 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>
> ktime_get_ts64(&start);
> ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
> - phys_addr, reg->size);
> + src_phys_addr, reg->size, dir);
> + ktime_get_ts64(&end);
> if (ret)
> dev_err(dev, "Data transfer failed\n");
> - ktime_get_ts64(&end);
>
> dma_unmap_single(dma_dev, dst_phys_addr, reg->size,
> DMA_FROM_DEVICE);
> @@ -383,10 +403,10 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
> kfree(buf);
>
> err_map_addr:
> - pci_epc_unmap_addr(epc, epf->func_no, phys_addr);
> + pci_epc_unmap_addr(epc, epf->func_no, src_phys_addr);
>
> err_addr:
> - pci_epc_mem_free_addr(epc, phys_addr, src_addr, reg->size);
> + pci_epc_mem_free_addr(epc, src_phys_addr, src_addr, reg->size);
>
> err:
> return ret;
> @@ -398,7 +418,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> void __iomem *dst_addr;
> void *buf;
> bool use_dma;
> - phys_addr_t phys_addr;
> + phys_addr_t dst_phys_addr;
> phys_addr_t src_phys_addr;
> struct timespec64 start, end;
> struct pci_epf *epf = epf_test->epf;
> @@ -407,8 +427,9 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> struct device *dma_dev = epf->epc->dev.parent;
> enum pci_barno test_reg_bar = epf_test->test_reg_bar;
> struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
> + enum dma_transfer_direction dir = DMA_MEM_TO_MEM;
>
> - dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
> + dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
> if (!dst_addr) {
> dev_err(dev, "Failed to allocate address\n");
> reg->status = STATUS_DST_ADDR_INVALID;
> @@ -416,7 +437,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> goto err;
> }
>
> - ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->dst_addr,
> + ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, reg->dst_addr,
> reg->size);
> if (ret) {
> dev_err(dev, "Failed to map address\n");
> @@ -450,11 +471,11 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> }
>
> ktime_get_ts64(&start);
> - ret = pci_epf_test_data_transfer(epf_test, phys_addr,
> - src_phys_addr, reg->size);
> + ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
> + src_phys_addr, reg->size, dir);
> + ktime_get_ts64(&end);
> if (ret)
> dev_err(dev, "Data transfer failed\n");
> - ktime_get_ts64(&end);
>
> dma_unmap_single(dma_dev, src_phys_addr, reg->size,
> DMA_TO_DEVICE);
> @@ -476,10 +497,10 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
> kfree(buf);
>
> err_map_addr:
> - pci_epc_unmap_addr(epc, epf->func_no, phys_addr);
> + pci_epc_unmap_addr(epc, epf->func_no, dst_phys_addr);
>
> err_addr:
> - pci_epc_mem_free_addr(epc, phys_addr, dst_addr, reg->size);
> + pci_epc_mem_free_addr(epc, dst_phys_addr, dst_addr, reg->size);
>
> err:
> return ret;
> --
> 2.7.4
>