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Subject[RFC PATCH 2/5] PCI: endpoint: Add support to data transfer using internal dmac
Date
For PCIe EP capable with internal DMAC, transfer data using this
when -d option is used with pcitest.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 184 ++++++++++++++----
1 file changed, 141 insertions(+), 43 deletions(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index 90d84d3bc868..f792b1a15c44 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -55,6 +55,7 @@ struct pci_epf_test {
struct dma_chan *dma_chan;
struct completion transfer_complete;
bool dma_supported;
+ bool internal_dmac;
const struct pci_epc_features *epc_features;
};

@@ -148,6 +149,40 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test,
return 0;
}

+/**
+ * pci_epf_test_internal_dmac_data_transfer() - Function that uses internal DMAC
+ * to transfer data between PCIe EP and remote PCIe RC
+ * @epf_test: the EPF test device that performs the data transfer operation
+ * @dma_dst: The destination address of the data transfer. It can be a physical
+ * address given by pci_epc_mem_alloc_addr or DMA mapping APIs.
+ * @dma_src: The source address of the data transfer. It can be a physical
+ * address given by pci_epc_mem_alloc_addr or DMA mapping APIs.
+ * @len: The size of the data transfer
+ * @dir: Direction of data transfer
+ *
+ * Function that uses internal dmac supported by the controller to transfer data
+ * between PCIe EP and remote PCIe RC.
+ *
+ * The function returns '0' on success and negative value on failure.
+ */
+static int
+pci_epf_test_internal_dmac_data_transfer(struct pci_epf_test *epf_test,
+ dma_addr_t dma_dst, dma_addr_t dma_src,
+ size_t len, enum pci_epf_xfr_direction dir)
+{
+ struct pci_epf *epf = epf_test->epf;
+ int ret;
+
+ if (!epf_test->internal_dmac)
+ return -EINVAL;
+
+ ret = pci_epf_internal_dmac_xfr(epf, dma_dst, dma_src, len, dir);
+ if (ret)
+ return -EIO;
+
+ return 0;
+}
+
/**
* pci_epf_test_init_dma_chan() - Function to initialize EPF test DMA channel
* @epf_test: the EPF test device that performs data transfer operation
@@ -238,6 +273,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
struct pci_epc *epc = epf->epc;
enum pci_barno test_reg_bar = epf_test->test_reg_bar;
struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
+ bool internal_dmac = epf_test->internal_dmac;
+
+ use_dma = !!(reg->flags & FLAG_USE_DMA);
+
+ if (use_dma && internal_dmac) {
+ dev_err(dev, "Operation not supported\n");
+ return -EINVAL;
+ }

src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
if (!src_addr) {
@@ -272,7 +315,6 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
}

ktime_get_ts64(&start);
- use_dma = !!(reg->flags & FLAG_USE_DMA);
if (use_dma) {
if (!epf_test->dma_supported) {
dev_err(dev, "Cannot transfer data using DMA\n");
@@ -322,31 +364,49 @@ 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];
+ bool internal_dmac = epf_test->internal_dmac;

- src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
- if (!src_addr) {
- dev_err(dev, "Failed to allocate address\n");
- reg->status = STATUS_SRC_ADDR_INVALID;
- ret = -ENOMEM;
- goto err;
- }
+ use_dma = !!(reg->flags & FLAG_USE_DMA);

- ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
- reg->src_addr, reg->size);
- if (ret) {
- dev_err(dev, "Failed to map address\n");
- reg->status = STATUS_SRC_ADDR_INVALID;
- goto err_addr;
+ if (use_dma && internal_dmac) {
+ phys_addr = reg->src_addr;
+ src_addr = NULL;
+ } else {
+ src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
+ if (!src_addr) {
+ dev_err(dev, "Failed to allocate address\n");
+ reg->status = STATUS_SRC_ADDR_INVALID;
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
+ reg->src_addr, reg->size);
+ if (ret) {
+ dev_err(dev, "Failed to map address\n");
+ reg->status = STATUS_SRC_ADDR_INVALID;
+ goto err_addr;
+ }
}

- buf = kzalloc(reg->size, GFP_KERNEL);
+ if (use_dma && internal_dmac)
+ buf = dma_alloc_coherent(dev, reg->size, &dst_phys_addr, GFP_KERNEL | GFP_DMA);
+ else
+ buf = kzalloc(reg->size, GFP_KERNEL);
if (!buf) {
ret = -ENOMEM;
goto err_map_addr;
}

- use_dma = !!(reg->flags & FLAG_USE_DMA);
- if (use_dma) {
+ if (use_dma && internal_dmac) {
+ ktime_get_ts64(&start);
+ ret = pci_epf_test_internal_dmac_data_transfer(epf_test, dst_phys_addr,
+ phys_addr, reg->size,
+ PCIE_TO_INTERNAL);
+ if (ret)
+ dev_err(dev, "Data transfer failed\n");
+ ktime_get_ts64(&end);
+ } else if (use_dma) {
if (!epf_test->dma_supported) {
dev_err(dev, "Cannot transfer data using DMA\n");
ret = -EINVAL;
@@ -383,13 +443,18 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
ret = -EIO;

err_dma_map:
- kfree(buf);
+ if (use_dma && internal_dmac)
+ dma_free_coherent(dev, reg->size, buf, dst_phys_addr);
+ else
+ kfree(buf);

err_map_addr:
- pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);
+ if (!(use_dma && internal_dmac))
+ pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);

err_addr:
- pci_epc_mem_free_addr(epc, phys_addr, src_addr, reg->size);
+ if (!(use_dma && internal_dmac))
+ pci_epc_mem_free_addr(epc, phys_addr, src_addr, reg->size);

err:
return ret;
@@ -410,24 +475,36 @@ 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];
+ bool internal_dmac = epf_test->internal_dmac;

- dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
- if (!dst_addr) {
- dev_err(dev, "Failed to allocate address\n");
- reg->status = STATUS_DST_ADDR_INVALID;
- ret = -ENOMEM;
- goto err;
- }
+ use_dma = !!(reg->flags & FLAG_USE_DMA);

- ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
- reg->dst_addr, reg->size);
- if (ret) {
- dev_err(dev, "Failed to map address\n");
- reg->status = STATUS_DST_ADDR_INVALID;
- goto err_addr;
+ if (use_dma && internal_dmac) {
+ phys_addr = reg->dst_addr;
+ dst_addr = NULL;
+ } else {
+ dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
+ if (!dst_addr) {
+ dev_err(dev, "Failed to allocate address\n");
+ reg->status = STATUS_DST_ADDR_INVALID;
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ ret = pci_epc_map_addr(epc, epf->func_no, epf->vfunc_no, phys_addr,
+ reg->dst_addr, reg->size);
+ if (ret) {
+ dev_err(dev, "Failed to map address\n");
+ reg->status = STATUS_DST_ADDR_INVALID;
+ goto err_addr;
+ }
}

- buf = kzalloc(reg->size, GFP_KERNEL);
+ if (use_dma && internal_dmac)
+ buf = dma_alloc_coherent(dev, reg->size,
+ &src_phys_addr, GFP_KERNEL | GFP_DMA);
+ else
+ buf = kzalloc(reg->size, GFP_KERNEL);
if (!buf) {
ret = -ENOMEM;
goto err_map_addr;
@@ -436,8 +513,15 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
get_random_bytes(buf, reg->size);
reg->checksum = crc32_le(~0, buf, reg->size);

- use_dma = !!(reg->flags & FLAG_USE_DMA);
- if (use_dma) {
+ if (use_dma && internal_dmac) {
+ ktime_get_ts64(&start);
+ ret = pci_epf_test_internal_dmac_data_transfer(epf_test, phys_addr,
+ src_phys_addr, reg->size,
+ INTERNAL_TO_PCIE);
+ if (ret)
+ dev_err(dev, "Data transfer failed\n");
+ ktime_get_ts64(&end);
+ } else if (use_dma) {
if (!epf_test->dma_supported) {
dev_err(dev, "Cannot transfer data using DMA\n");
ret = -EINVAL;
@@ -476,13 +560,18 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
usleep_range(1000, 2000);

err_dma_map:
- kfree(buf);
+ if (use_dma && internal_dmac)
+ dma_free_coherent(dev, reg->size, buf, src_phys_addr);
+ else
+ kfree(buf);

err_map_addr:
- pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);
+ if (!(use_dma && internal_dmac))
+ pci_epc_unmap_addr(epc, epf->func_no, epf->vfunc_no, phys_addr);

err_addr:
- pci_epc_mem_free_addr(epc, phys_addr, dst_addr, reg->size);
+ if (!(use_dma && internal_dmac))
+ pci_epc_mem_free_addr(epc, phys_addr, dst_addr, reg->size);

err:
return ret;
@@ -838,6 +927,7 @@ static int pci_epf_test_bind(struct pci_epf *epf)
struct pci_epc *epc = epf->epc;
bool linkup_notifier = false;
bool core_init_notifier = false;
+ struct device *dev = &epf->dev;

if (WARN_ON_ONCE(!epc))
return -EINVAL;
@@ -857,6 +947,12 @@ static int pci_epf_test_bind(struct pci_epf *epf)

epf_test->test_reg_bar = test_reg_bar;
epf_test->epc_features = epc_features;
+ epf_test->internal_dmac = epc_features->internal_dmac;
+ if (epf_test->internal_dmac && epc_features->internal_dmac_mask) {
+ ret = dma_set_coherent_mask(dev, epc_features->internal_dmac_mask);
+ if (ret)
+ return ret;
+ }

ret = pci_epf_test_alloc_space(epf);
if (ret)
@@ -868,11 +964,13 @@ static int pci_epf_test_bind(struct pci_epf *epf)
return ret;
}

- epf_test->dma_supported = true;
+ epf_test->dma_supported = false;

- ret = pci_epf_test_init_dma_chan(epf_test);
- if (ret)
- epf_test->dma_supported = false;
+ if (!epf_test->internal_dmac) {
+ ret = pci_epf_test_init_dma_chan(epf_test);
+ if (!ret)
+ epf_test->dma_supported = true;
+ }

if (linkup_notifier) {
epf->nb.notifier_call = pci_epf_test_notifier;
--
2.25.1
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