Use dmaengine API and add support for transferring data using DMA.
Signed-off-by: Kishon Vijay Abraham I <kishon@xxxxxx>
Tested-by: Alan Mikhak <alan.mikhak@xxxxxxxxxx>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 205 +++++++++++++++++-
1 file changed, 202 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index bddff15052cc..c9d9d1780e66 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -8,6 +8,7 @@
#include <linux/crc32.h>
#include <linux/delay.h>
+#include <linux/dmaengine.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/slab.h>
@@ -39,6 +40,8 @@
#define STATUS_SRC_ADDR_INVALID BIT(7)
#define STATUS_DST_ADDR_INVALID BIT(8)
+#define FLAG_USE_DMA BIT(0)
+
#define TIMER_RESOLUTION 1
static struct workqueue_struct *kpcitest_workqueue;
@@ -48,6 +51,9 @@ struct pci_epf_test {
struct pci_epf *epf;
enum pci_barno test_reg_bar;
struct delayed_work cmd_handler;
+ struct dma_chan *dma_chan;
+ struct completion transfer_complete;
+ bool dma_supported;
const struct pci_epc_features *epc_features;
};
@@ -61,6 +67,7 @@ struct pci_epf_test_reg {
u32 checksum;
u32 irq_type;
u32 irq_number;
+ u32 flags;
} __packed;
static struct pci_epf_header test_header = {
@@ -72,9 +79,121 @@ static struct pci_epf_header test_header = {
static size_t bar_size[] = { 512, 512, 1024, 16384, 131072, 1048576 };
+static void pci_epf_test_dma_callback(void *param)
+{
+ struct pci_epf_test *epf_test = param;
+
+ complete(&epf_test->transfer_complete);
+}
+
+/**
+ * pci_epf_test_data_transfer() - Function that uses dmaengine API 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
+ *
+ * Function that uses dmaengine API to transfer data between PCIe EP and remote
+ * PCIe RC. The source and destination address can be a physical address given
+ * by pci_epc_mem_alloc_addr or the one obtained using DMA mapping APIs.
+ *
+ * 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)
+{
+ 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_async_tx_descriptor *tx;
+ struct device *dev = &epf->dev;
+ dma_cookie_t cookie;
+ int ret;
+
+ if (IS_ERR_OR_NULL(chan)) {
+ dev_err(dev, "Invalid DMA memcpy channel\n");
+ return -EINVAL;
+ }
+
+ tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags);
+ if (!tx) {
+ dev_err(dev, "Failed to prepare DMA memcpy\n");
+ return -EIO;
+ }
+
+ tx->callback = pci_epf_test_dma_callback;
+ tx->callback_param = epf_test;
+ cookie = tx->tx_submit(tx);
+ reinit_completion(&epf_test->transfer_complete);
+
+ ret = dma_submit_error(cookie);
+ if (ret) {
+ dev_err(dev, "Failed to do DMA tx_submit %d\n", cookie);
+ return -EIO;
+ }
+
+ dma_async_issue_pending(chan);
+ ret = wait_for_completion_interruptible(&epf_test->transfer_complete);
+ if (ret < 0) {
+ dmaengine_terminate_sync(chan);
+ dev_err(dev, "DMA wait_for_completion_timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ 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
+ *
+ * Function to initialize EPF test DMA channel.
+ */
+static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test)
+{
+ struct pci_epf *epf = epf_test->epf;
+ struct device *dev = &epf->dev;
+ struct dma_chan *dma_chan;
+ dma_cap_mask_t mask;
+ int ret;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_MEMCPY, mask);
+
+ dma_chan = dma_request_chan_by_mask(&mask);
+ if (IS_ERR(dma_chan)) {
+ ret = PTR_ERR(dma_chan);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "Failed to get DMA channel\n");
+ return ret;
+ }
+ init_completion(&epf_test->transfer_complete);
+
+ epf_test->dma_chan = dma_chan;
+
+ return 0;
+}
+
+/**
+ * pci_epf_test_clean_dma_chan() - Function to cleanup EPF test DMA channel
+ * @epf: the EPF test device that performs data transfer operation
+ *
+ * Helper to cleanup EPF test DMA channel.
+ */
+static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test)
+{
+ dma_release_channel(epf_test->dma_chan);
+ epf_test->dma_chan = NULL;
+}
+
static int pci_epf_test_copy(struct pci_epf_test *epf_test)
{
int ret;
+ bool use_dma;
void __iomem *src_addr;
void __iomem *dst_addr;
phys_addr_t src_phys_addr;
@@ -117,8 +236,23 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
goto err_dst_addr;
}
- memcpy(dst_addr, src_addr, reg->size);
+ use_dma = !!(reg->flags & FLAG_USE_DMA);
+ if (use_dma) {
+ if (!epf_test->dma_supported) {
+ dev_err(dev, "Cannot transfer data using DMA\n");
+ ret = -EINVAL;
+ goto err_map_addr;
+ }
+ ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
+ src_phys_addr, reg->size);
+ if (ret)
+ dev_err(dev, "Data transfer failed\n");
+ } else {
+ memcpy(dst_addr, src_addr, reg->size);
+ }
+
+err_map_addr:
pci_epc_unmap_addr(epc, epf->func_no, dst_phys_addr);
err_dst_addr:
@@ -140,10 +274,13 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
void __iomem *src_addr;
void *buf;
u32 crc32;
+ bool use_dma;
phys_addr_t phys_addr;
+ phys_addr_t dst_phys_addr;
struct pci_epf *epf = epf_test->epf;
struct device *dev = &epf->dev;
struct pci_epc *epc = epf->epc;
+ 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];
@@ -169,12 +306,38 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
goto err_map_addr;
}
- memcpy_fromio(buf, src_addr, reg->size);
+ use_dma = !!(reg->flags & FLAG_USE_DMA);
+ if (use_dma) {
+ if (!epf_test->dma_supported) {
+ dev_err(dev, "Cannot transfer data using DMA\n");
+ ret = -EINVAL;
+ goto err_map_addr;
+ }
+
+ dst_phys_addr = dma_map_single(dma_dev, buf, reg->size,
+ DMA_FROM_DEVICE);
+ if (dma_mapping_error(dma_dev, dst_phys_addr)) {
+ dev_err(dev, "Failed to map destination buffer addr\n");
+ ret = -ENOMEM;
+ goto err_dma_map;
+ }
+
+ ret = pci_epf_test_data_transfer(epf_test, dst_phys_addr,
+ phys_addr, reg->size);
+ if (ret)
+ dev_err(dev, "Data transfer failed\n");
+
+ dma_unmap_single(dma_dev, dst_phys_addr, reg->size,
+ DMA_FROM_DEVICE);
+ } else {
+ memcpy_fromio(buf, src_addr, reg->size);
+ }
crc32 = crc32_le(~0, buf, reg->size);
if (crc32 != reg->checksum)
ret = -EIO;
+err_dma_map:
kfree(buf);
err_map_addr:
@@ -192,10 +355,13 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
int ret;
void __iomem *dst_addr;
void *buf;
+ bool use_dma;
phys_addr_t phys_addr;
+ phys_addr_t src_phys_addr;
struct pci_epf *epf = epf_test->epf;
struct device *dev = &epf->dev;
struct pci_epc *epc = epf->epc;
+ 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];
@@ -224,7 +390,32 @@ 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);
- memcpy_toio(dst_addr, buf, reg->size);
+ use_dma = !!(reg->flags & FLAG_USE_DMA);
+ if (use_dma) {
+ if (!epf_test->dma_supported) {
+ dev_err(dev, "Cannot transfer data using DMA\n");
+ ret = -EINVAL;
+ goto err_map_addr;
+ }
+
+ src_phys_addr = dma_map_single(dma_dev, buf, reg->size,
+ DMA_TO_DEVICE);
+ if (dma_mapping_error(dma_dev, src_phys_addr)) {
+ dev_err(dev, "Failed to map source buffer addr\n");
+ ret = -ENOMEM;
+ goto err_dma_map;
+ }
+
+ ret = pci_epf_test_data_transfer(epf_test, phys_addr,
+ src_phys_addr, reg->size);
+ if (ret)
+ dev_err(dev, "Data transfer failed\n");
+
+ dma_unmap_single(dma_dev, src_phys_addr, reg->size,
+ DMA_TO_DEVICE);
+ } else {
+ memcpy_toio(dst_addr, buf, reg->size);
+ }
/*
* wait 1ms inorder for the write to complete. Without this delay L3
@@ -232,6 +423,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
*/
usleep_range(1000, 2000);
+err_dma_map:
kfree(buf);
err_map_addr:
@@ -380,6 +572,7 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
int bar;
cancel_delayed_work(&epf_test->cmd_handler);
+ pci_epf_test_clean_dma_chan(epf_test);
pci_epc_stop(epc);
for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
epf_bar = &epf->bar[bar];
@@ -550,6 +743,12 @@ static int pci_epf_test_bind(struct pci_epf *epf)
}
}
+ epf_test->dma_supported = true;
+
+ ret = pci_epf_test_init_dma_chan(epf_test);
+ if (ret)
+ epf_test->dma_supported = false;
+
if (linkup_notifier) {
epf->nb.notifier_call = pci_epf_test_notifier;
pci_epc_register_notifier(epc, &epf->nb);
--
2.17.1
