| Message ID | 20220517151915.2212838-9-Frank.Li@nxp.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Enable designware PCI EP EDMA locally | expand |
On Tue, May 17, 2022 at 10:19:15AM -0500, Frank Li wrote: > Some PCI Endpoints controllers integrate an eDMA (embedded DMA). > eDMA only sends once a bus read/write command to complete once > data transfer. eDMA can bypass the outbound memory address translation > unit to access all RC memory space. s/Endpoints/Endpoint/ I'm not sure what "only sends once a command to complete once transfer" means or why it is revelant here. I guess it just means "the eDMA controller issues a single bus command per data transfer"? > Add DMA support for pci-epf-test. It looks like pci-epf-test.c already *has* DMA support, but you're adding support for separate RX and TX DMA channels. > EPF test can use, depending on HW availability, eDMA or general system > DMA controllers to perform DMA. The test probes the EPF DMA channel > capabilities. > > Separate dma_chan to dma_chan_tx and dma_chan_rx. eDMA channels have > higher priority than general DMA channels. I think the "priority" you refer to is merely that the *test* uses eDMA channels if present, not that there's any actual hardware priority involved here, right? > If general memory to memory > DMA hannels are used, dma_chan_rx = dma_chan_tx. s/hannels/channels/ > Add dma_addr_t dma_remote in function pci_epf_test_data_transfer() > because eDMA using remote RC physical address directly s/function pci_epf_test_data_transfer()/pci_epf_test_data_transfer()/ s/eDMA using/eDMA uses/ s/directly/directly./ (No need to specify "function" since the parens make it obvious that pci_epf_test_data_transfer() is a function. Same thing below.) > Add enum dma_transfer_direction dir in function pci_epf_test_data_transfer() > because eDMA chooses the correct RX/TX channel by dir. > > The overall steps are > > 1. Execute dma_request_channel() and filter function to find correct eDMA > RX and TX Channel. If a channel does not exist, fallback to try to allocate > general memory to memory DMA channel. s/exist, /exist, / remove extra space s/memory DMA /memory DMA / remove extra space again > 2. Execute dmaengine_slave_config() to configure remote side physical address. Rewrap to fit in 75 columns. > 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. > 4. Execute tx_submit(). > 5. Execute dma_async_issue_pending() > > Signed-off-by: Frank Li <Frank.Li@nxp.com> > Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > --- > Change from v10 to v11: > - rewrite commit message > Change from v9 to v10: > - rewrite commit message > Change from v4 to v9: > - none > Change from v3 to v4: > - reverse Xmas tree order > - local -> dma_local > - change error message > - IS_ERR -> IS_ERR_OR_NULL > - check return value of dmaengine_slave_config() > Change from v1 to v2: > - none > > drivers/pci/endpoint/functions/pci-epf-test.c | 108 ++++++++++++++++-- > 1 file changed, 98 insertions(+), 10 deletions(-) > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > index 90d84d3bc868f..f26afd02f3a86 100644 > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > @@ -52,9 +52,11 @@ struct pci_epf_test { > enum pci_barno test_reg_bar; > size_t msix_table_offset; > struct delayed_work cmd_handler; > - struct dma_chan *dma_chan; > + struct dma_chan *dma_chan_tx; > + struct dma_chan *dma_chan_rx; > struct completion transfer_complete; > bool dma_supported; > + bool dma_private; > const struct pci_epc_features *epc_features; > }; > > @@ -105,12 +107,15 @@ static void pci_epf_test_dma_callback(void *param) > */ > 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) > + size_t len, dma_addr_t dma_remote, > + enum dma_transfer_direction dir) Please update the kernel-doc for these two new parameters. You can use: $ make W=1 drivers/pci/endpoint/functions/ to find errors like this. > { > + struct dma_chan *chan = (dir == DMA_DEV_TO_MEM) ? epf_test->dma_chan_tx : epf_test->dma_chan_rx; > + dma_addr_t dma_local = (dir == DMA_MEM_TO_DEV) ? dma_src : dma_dst; > 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 dma_slave_config sconf = {}; > struct device *dev = &epf->dev; > dma_cookie_t cookie; > int ret; > @@ -120,7 +125,22 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > return -EINVAL; > } > > - tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags); > + if (epf_test->dma_private) { > + sconf.direction = dir; > + if (dir == DMA_MEM_TO_DEV) > + sconf.dst_addr = dma_remote; > + else > + sconf.src_addr = dma_remote; > + > + if (dmaengine_slave_config(chan, &sconf)) { > + dev_err(dev, "DMA slave config fail\n"); > + return -EIO; > + } > + tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags); > + } else { > + 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; > @@ -148,6 +168,23 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > return 0; > } > > +struct epf_dma_filter { > + struct device *dev; > + u32 dma_mask; > +}; > + > +static bool epf_dma_filter_fn(struct dma_chan *chan, void *node) > +{ > + struct epf_dma_filter *filter = node; > + struct dma_slave_caps caps; > + > + memset(&caps, 0, sizeof(caps)); > + dma_get_slave_caps(chan, &caps); > + > + return chan->device->dev == filter->dev > + && (filter->dma_mask & caps.directions); > +} > + > /** > * pci_epf_test_init_dma_chan() - Function to initialize EPF test DMA channel > * @epf_test: the EPF test device that performs data transfer operation > @@ -158,10 +195,44 @@ 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 epf_dma_filter filter; > struct dma_chan *dma_chan; > dma_cap_mask_t mask; > int ret; > > + filter.dev = epf->epc->dev.parent; > + filter.dma_mask = BIT(DMA_DEV_TO_MEM); > + > + dma_cap_zero(mask); > + dma_cap_set(DMA_SLAVE, mask); > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > + if (IS_ERR_OR_NULL(dma_chan)) { > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); > + goto fail_back_tx; > + } > + > + epf_test->dma_chan_rx = dma_chan; > + > + filter.dma_mask = BIT(DMA_MEM_TO_DEV); > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > + > + if (IS_ERR(dma_chan)) { > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); These messages should indicate whether the failure was for the DEV_TO_MEM channel or the MEM_TO_DEV channel. Otherwise the failure looks the same to the user. > + goto fail_back_rx; > + } > + > + epf_test->dma_chan_tx = dma_chan; > + epf_test->dma_private = true; > + > + init_completion(&epf_test->transfer_complete); > + > + return 0; > + > +fail_back_rx: > + dma_release_channel(epf_test->dma_chan_rx); > + epf_test->dma_chan_tx = NULL; > + > +fail_back_tx: > dma_cap_zero(mask); > dma_cap_set(DMA_MEMCPY, mask); > > @@ -174,7 +245,7 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test) > } > init_completion(&epf_test->transfer_complete); > > - epf_test->dma_chan = dma_chan; > + epf_test->dma_chan_tx = epf_test->dma_chan_rx = dma_chan; > > return 0; > } > @@ -190,8 +261,17 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test) > if (!epf_test->dma_supported) > return; > > - dma_release_channel(epf_test->dma_chan); > - epf_test->dma_chan = NULL; > + dma_release_channel(epf_test->dma_chan_tx); > + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { > + epf_test->dma_chan_tx = NULL; > + epf_test->dma_chan_rx = NULL; > + return; > + } > + > + dma_release_channel(epf_test->dma_chan_rx); > + epf_test->dma_chan_rx = NULL; > + > + return; > } > > static void pci_epf_test_print_rate(const char *ops, u64 size, > @@ -280,8 +360,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test) > goto err_map_addr; > } > > + if (epf_test->dma_private) { > + 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); > + src_phys_addr, reg->size, 0, DMA_MEM_TO_MEM); > if (ret) > dev_err(dev, "Data transfer failed\n"); > } else { > @@ -363,7 +449,8 @@ 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); > + phys_addr, reg->size, > + reg->src_addr, DMA_DEV_TO_MEM); > if (ret) > dev_err(dev, "Data transfer failed\n"); > ktime_get_ts64(&end); > @@ -453,8 +540,9 @@ 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); > + src_phys_addr, reg->size, reg->dst_addr, DMA_MEM_TO_DEV); Wrap to fit in 80 columns, like the rest of the file. There are a couple other cases above (the dev_info() cases are fine since we don't want to split info/error message strings). > if (ret) > dev_err(dev, "Data transfer failed\n"); > ktime_get_ts64(&end); > -- > 2.35.1 >
On Mon, May 23, 2022 at 1:22 PM Bjorn Helgaas <helgaas@kernel.org> wrote: > > On Tue, May 17, 2022 at 10:19:15AM -0500, Frank Li wrote: > > Some PCI Endpoints controllers integrate an eDMA (embedded DMA). > > eDMA only sends once a bus read/write command to complete once > > data transfer. eDMA can bypass the outbound memory address translation > > unit to access all RC memory space. > > s/Endpoints/Endpoint/ > > I'm not sure what "only sends once a command to complete once > transfer" means or why it is revelant here. I guess it just means > "the eDMA controller issues a single bus command per data transfer"? > > > Add DMA support for pci-epf-test. > > It looks like pci-epf-test.c already *has* DMA support, but you're > adding support for separate RX and TX DMA channels. pci-epf-test already has memory to memory DMA support. I added eDMA support. > > > EPF test can use, depending on HW availability, eDMA or general system > > DMA controllers to perform DMA. The test probes the EPF DMA channel > > capabilities. > > > > Separate dma_chan to dma_chan_tx and dma_chan_rx. eDMA channels have > > higher priority than general DMA channels. > > I think the "priority" you refer to is merely that the *test* uses > eDMA channels if present, not that there's any actual hardware > priority involved here, right? Yes, choose EDMA channel first if it exists, then choose memory to memory dma channel. > > > If general memory to memory > > DMA hannels are used, dma_chan_rx = dma_chan_tx. > > s/hannels/channels/ > > > Add dma_addr_t dma_remote in function pci_epf_test_data_transfer() > > because eDMA using remote RC physical address directly > > s/function pci_epf_test_data_transfer()/pci_epf_test_data_transfer()/ > s/eDMA using/eDMA uses/ > s/directly/directly./ > > (No need to specify "function" since the parens make it obvious that > pci_epf_test_data_transfer() is a function. Same thing below.) > > > Add enum dma_transfer_direction dir in function pci_epf_test_data_transfer() > > because eDMA chooses the correct RX/TX channel by dir. > > > > The overall steps are > > > > 1. Execute dma_request_channel() and filter function to find correct eDMA > > RX and TX Channel. If a channel does not exist, fallback to try to allocate > > general memory to memory DMA channel. > > s/exist, /exist, / remove extra space > s/memory DMA /memory DMA / remove extra space again > > > 2. Execute dmaengine_slave_config() to configure remote side physical address. > > Rewrap to fit in 75 columns. > > > 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. > > 4. Execute tx_submit(). > > 5. Execute dma_async_issue_pending() > > > > Signed-off-by: Frank Li <Frank.Li@nxp.com> > > Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> > > --- Bjorn: Are you satisfied with the below message? I will fix the other code in the next version. Some PCI Endpoint controllers integrate an eDMA (embedded DMA). The eDMA controller issues a single bus command per data transfer. eDMA can bypass the outbound memory address translation unit to access all RC memory space. Add eDMA support for pci-epf-test. EPF test can use, depending on HW availability, eDMA or general system DMA controllers to perform DMA. The test probes the EPF DMA channel capabilities. Separate dma_chan to dma_chan_tx and dma_chan_rx. Search eDMA channel firstly, then search memory to memory DMA channel if eDMA does not exist. If general memory to memory channels are used, dma_chan_rx = dma_chan_tx. Add dma_addr_t dma_remote in pci_epf_test_data_transfer() because eDMA uses remote RC physical address directly. Add enum dma_transfer_direction dir in pci_epf_test_data_transfer() because eDMA chooses the correct RX/TX channel by dir. The overall steps are 1. Execute dma_request_channel() and filter function to find correct eDMA RX and TX Channel. If a channel does not exist, fallback to try to allocate general memory to memory DMA channel. 2. Execute dmaengine_slave_config() to configure remote side physical address. 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. 4. Execute tx_submit(). 5. Execute dma_async_issue_pending() > > Change from v10 to v11: > > - rewrite commit message > > Change from v9 to v10: > > - rewrite commit message > > Change from v4 to v9: > > - none > > Change from v3 to v4: > > - reverse Xmas tree order > > - local -> dma_local > > - change error message > > - IS_ERR -> IS_ERR_OR_NULL > > - check return value of dmaengine_slave_config() > > Change from v1 to v2: > > - none > > > > drivers/pci/endpoint/functions/pci-epf-test.c | 108 ++++++++++++++++-- > > 1 file changed, 98 insertions(+), 10 deletions(-) > > > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > > index 90d84d3bc868f..f26afd02f3a86 100644 > > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > > @@ -52,9 +52,11 @@ struct pci_epf_test { > > enum pci_barno test_reg_bar; > > size_t msix_table_offset; > > struct delayed_work cmd_handler; > > - struct dma_chan *dma_chan; > > + struct dma_chan *dma_chan_tx; > > + struct dma_chan *dma_chan_rx; > > struct completion transfer_complete; > > bool dma_supported; > > + bool dma_private; > > const struct pci_epc_features *epc_features; > > }; > > > > @@ -105,12 +107,15 @@ static void pci_epf_test_dma_callback(void *param) > > */ > > 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) > > + size_t len, dma_addr_t dma_remote, > > + enum dma_transfer_direction dir) > > Please update the kernel-doc for these two new parameters. You can > use: > > $ make W=1 drivers/pci/endpoint/functions/ > > to find errors like this. > > > { > > + struct dma_chan *chan = (dir == DMA_DEV_TO_MEM) ? epf_test->dma_chan_tx : epf_test->dma_chan_rx; > > + dma_addr_t dma_local = (dir == DMA_MEM_TO_DEV) ? dma_src : dma_dst; > > 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 dma_slave_config sconf = {}; > > struct device *dev = &epf->dev; > > dma_cookie_t cookie; > > int ret; > > @@ -120,7 +125,22 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > > return -EINVAL; > > } > > > > - tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags); > > + if (epf_test->dma_private) { > > + sconf.direction = dir; > > + if (dir == DMA_MEM_TO_DEV) > > + sconf.dst_addr = dma_remote; > > + else > > + sconf.src_addr = dma_remote; > > + > > + if (dmaengine_slave_config(chan, &sconf)) { > > + dev_err(dev, "DMA slave config fail\n"); > > + return -EIO; > > + } > > + tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags); > > + } else { > > + 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; > > @@ -148,6 +168,23 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > > return 0; > > } > > > > +struct epf_dma_filter { > > + struct device *dev; > > + u32 dma_mask; > > +}; > > + > > +static bool epf_dma_filter_fn(struct dma_chan *chan, void *node) > > +{ > > + struct epf_dma_filter *filter = node; > > + struct dma_slave_caps caps; > > + > > + memset(&caps, 0, sizeof(caps)); > > + dma_get_slave_caps(chan, &caps); > > + > > + return chan->device->dev == filter->dev > > + && (filter->dma_mask & caps.directions); > > +} > > + > > /** > > * pci_epf_test_init_dma_chan() - Function to initialize EPF test DMA channel > > * @epf_test: the EPF test device that performs data transfer operation > > @@ -158,10 +195,44 @@ 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 epf_dma_filter filter; > > struct dma_chan *dma_chan; > > dma_cap_mask_t mask; > > int ret; > > > > + filter.dev = epf->epc->dev.parent; > > + filter.dma_mask = BIT(DMA_DEV_TO_MEM); > > + > > + dma_cap_zero(mask); > > + dma_cap_set(DMA_SLAVE, mask); > > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > > + if (IS_ERR_OR_NULL(dma_chan)) { > > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); > > + goto fail_back_tx; > > + } > > + > > + epf_test->dma_chan_rx = dma_chan; > > + > > + filter.dma_mask = BIT(DMA_MEM_TO_DEV); > > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > > + > > + if (IS_ERR(dma_chan)) { > > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); > > These messages should indicate whether the failure was for the > DEV_TO_MEM channel or the MEM_TO_DEV channel. Otherwise the failure > looks the same to the user. > > > + goto fail_back_rx; > > + } > > + > > + epf_test->dma_chan_tx = dma_chan; > > + epf_test->dma_private = true; > > + > > + init_completion(&epf_test->transfer_complete); > > + > > + return 0; > > + > > +fail_back_rx: > > + dma_release_channel(epf_test->dma_chan_rx); > > + epf_test->dma_chan_tx = NULL; > > + > > +fail_back_tx: > > dma_cap_zero(mask); > > dma_cap_set(DMA_MEMCPY, mask); > > > > @@ -174,7 +245,7 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test) > > } > > init_completion(&epf_test->transfer_complete); > > > > - epf_test->dma_chan = dma_chan; > > + epf_test->dma_chan_tx = epf_test->dma_chan_rx = dma_chan; > > > > return 0; > > } > > @@ -190,8 +261,17 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test) > > if (!epf_test->dma_supported) > > return; > > > > - dma_release_channel(epf_test->dma_chan); > > - epf_test->dma_chan = NULL; > > + dma_release_channel(epf_test->dma_chan_tx); > > + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { > > + epf_test->dma_chan_tx = NULL; > > + epf_test->dma_chan_rx = NULL; > > + return; > > + } > > + > > + dma_release_channel(epf_test->dma_chan_rx); > > + epf_test->dma_chan_rx = NULL; > > + > > + return; > > } > > > > static void pci_epf_test_print_rate(const char *ops, u64 size, > > @@ -280,8 +360,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test) > > goto err_map_addr; > > } > > > > + if (epf_test->dma_private) { > > + 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); > > + src_phys_addr, reg->size, 0, DMA_MEM_TO_MEM); > > if (ret) > > dev_err(dev, "Data transfer failed\n"); > > } else { > > @@ -363,7 +449,8 @@ 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); > > + phys_addr, reg->size, > > + reg->src_addr, DMA_DEV_TO_MEM); > > if (ret) > > dev_err(dev, "Data transfer failed\n"); > > ktime_get_ts64(&end); > > @@ -453,8 +540,9 @@ 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); > > + src_phys_addr, reg->size, reg->dst_addr, DMA_MEM_TO_DEV); > > Wrap to fit in 80 columns, like the rest of the file. There are a > couple other cases above (the dev_info() cases are fine since we don't > want to split info/error message strings). > > > if (ret) > > dev_err(dev, "Data transfer failed\n"); > > ktime_get_ts64(&end); > > -- > > 2.35.1 > >
On Mon, May 23, 2022 at 02:19:34PM -0500, Zhi Li wrote: > Bjorn: Are you satisfied with the below message? I will fix the > other code in the next version. Looks good, minor questions and tweaks below: > Some PCI Endpoint controllers integrate an eDMA (embedded DMA). > The eDMA controller issues a single bus command per data transfer. Still not sure why this sentence is here. Is it something the patch relies on? Why does it matter how many bus commands there are? > eDMA can bypass the outbound memory address translation unit to > access all RC memory space. > > Add eDMA support for pci-epf-test. > > EPF test can use, depending on HW availability, eDMA or general system > DMA controllers to perform DMA. The test probes the EPF DMA channel > capabilities. Depending on HW availability, the EPF test can use either eDMA or general system DMA controllers to perform DMA. The test tries to use eDMA first and falls back to general system DMA controllers if there's no eDMA. > Separate dma_chan to dma_chan_tx and dma_chan_rx. Search eDMA channel > firstly, then search memory to memory DMA channel if eDMA does not exist. > If general memory to memory channels are used, dma_chan_rx = dma_chan_tx. Search for an eDMA channel first, then search for a memory-to-memory DMA channel ... > Add dma_addr_t dma_remote in pci_epf_test_data_transfer() > because eDMA uses remote RC physical address directly. > > Add enum dma_transfer_direction dir in pci_epf_test_data_transfer() > because eDMA chooses the correct RX/TX channel by dir. > > The overall steps are > > 1. Execute dma_request_channel() and filter function to find correct > eDMA RX and TX Channel. If a channel does not exist, fallback to try to > allocate general memory to memory DMA channel. > 2. Execute dmaengine_slave_config() to configure remote side physical > address. > 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. > 4. Execute tx_submit(). > 5. Execute dma_async_issue_pending()
On Mon, May 23, 2022 at 5:18 PM Bjorn Helgaas <helgaas@kernel.org> wrote: > > On Mon, May 23, 2022 at 02:19:34PM -0500, Zhi Li wrote: > > > Bjorn: Are you satisfied with the below message? I will fix the > > other code in the next version. > > Looks good, minor questions and tweaks below: > > > Some PCI Endpoint controllers integrate an eDMA (embedded DMA). > > The eDMA controller issues a single bus command per data transfer. > > Still not sure why this sentence is here. Is it something the patch > relies on? Why does it matter how many bus commands there are? Okay, let me remove this line in the next version. > > > eDMA can bypass the outbound memory address translation unit to > > access all RC memory space. > > > > Add eDMA support for pci-epf-test. > > > > EPF test can use, depending on HW availability, eDMA or general system > > DMA controllers to perform DMA. The test probes the EPF DMA channel > > capabilities. > > Depending on HW availability, the EPF test can use either eDMA or > general system DMA controllers to perform DMA. The test tries to use > eDMA first and falls back to general system DMA controllers if > there's no eDMA. > > > Separate dma_chan to dma_chan_tx and dma_chan_rx. Search eDMA channel > > firstly, then search memory to memory DMA channel if eDMA does not exist. > > If general memory to memory channels are used, dma_chan_rx = dma_chan_tx. > > Search for an eDMA channel first, then search for a memory-to-memory > DMA channel ... > > > Add dma_addr_t dma_remote in pci_epf_test_data_transfer() > > because eDMA uses remote RC physical address directly. > > > > Add enum dma_transfer_direction dir in pci_epf_test_data_transfer() > > because eDMA chooses the correct RX/TX channel by dir. > > > > The overall steps are > > > > 1. Execute dma_request_channel() and filter function to find correct > > eDMA RX and TX Channel. If a channel does not exist, fallback to try to > > allocate general memory to memory DMA channel. > > 2. Execute dmaengine_slave_config() to configure remote side physical > > address. > > 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. > > 4. Execute tx_submit(). > > 5. Execute dma_async_issue_pending()
On 17/05/22 20:49, Frank Li wrote: > Some PCI Endpoints controllers integrate an eDMA (embedded DMA). > eDMA only sends once a bus read/write command to complete once > data transfer. eDMA can bypass the outbound memory address translation > unit to access all RC memory space. > > Add DMA support for pci-epf-test. > > EPF test can use, depending on HW availability, eDMA or general system > DMA controllers to perform DMA. The test probes the EPF DMA channel > capabilities. > > Separate dma_chan to dma_chan_tx and dma_chan_rx. eDMA channels have > higher priority than general DMA channels. If general memory to memory > DMA hannels are used, dma_chan_rx = dma_chan_tx. > > Add dma_addr_t dma_remote in function pci_epf_test_data_transfer() > because eDMA using remote RC physical address directly > > Add enum dma_transfer_direction dir in function pci_epf_test_data_transfer() > because eDMA chooses the correct RX/TX channel by dir. > > The overall steps are > > 1. Execute dma_request_channel() and filter function to find correct eDMA > RX and TX Channel. If a channel does not exist, fallback to try to allocate > general memory to memory DMA channel. > 2. Execute dmaengine_slave_config() to configure remote side physical address. > 3. Execute dmaengine_prep_slave_single() to create transfer descriptor. > 4. Execute tx_submit(). > 5. Execute dma_async_issue_pending() > > Signed-off-by: Frank Li <Frank.Li@nxp.com> > Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> Acked-by: Kishon Vijay Abraham I <kishon@ti.com> > --- > Change from v10 to v11: > - rewrite commit message > Change from v9 to v10: > - rewrite commit message > Change from v4 to v9: > - none > Change from v3 to v4: > - reverse Xmas tree order > - local -> dma_local > - change error message > - IS_ERR -> IS_ERR_OR_NULL > - check return value of dmaengine_slave_config() > Change from v1 to v2: > - none > > drivers/pci/endpoint/functions/pci-epf-test.c | 108 ++++++++++++++++-- > 1 file changed, 98 insertions(+), 10 deletions(-) > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > index 90d84d3bc868f..f26afd02f3a86 100644 > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > @@ -52,9 +52,11 @@ struct pci_epf_test { > enum pci_barno test_reg_bar; > size_t msix_table_offset; > struct delayed_work cmd_handler; > - struct dma_chan *dma_chan; > + struct dma_chan *dma_chan_tx; > + struct dma_chan *dma_chan_rx; > struct completion transfer_complete; > bool dma_supported; > + bool dma_private; > const struct pci_epc_features *epc_features; > }; > > @@ -105,12 +107,15 @@ static void pci_epf_test_dma_callback(void *param) > */ > 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) > + size_t len, dma_addr_t dma_remote, > + enum dma_transfer_direction dir) > { > + struct dma_chan *chan = (dir == DMA_DEV_TO_MEM) ? epf_test->dma_chan_tx : epf_test->dma_chan_rx; > + dma_addr_t dma_local = (dir == DMA_MEM_TO_DEV) ? dma_src : dma_dst; > 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 dma_slave_config sconf = {}; > struct device *dev = &epf->dev; > dma_cookie_t cookie; > int ret; > @@ -120,7 +125,22 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > return -EINVAL; > } > > - tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags); > + if (epf_test->dma_private) { > + sconf.direction = dir; > + if (dir == DMA_MEM_TO_DEV) > + sconf.dst_addr = dma_remote; > + else > + sconf.src_addr = dma_remote; > + > + if (dmaengine_slave_config(chan, &sconf)) { > + dev_err(dev, "DMA slave config fail\n"); > + return -EIO; > + } > + tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags); > + } else { > + 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; > @@ -148,6 +168,23 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, > return 0; > } > > +struct epf_dma_filter { > + struct device *dev; > + u32 dma_mask; > +}; > + > +static bool epf_dma_filter_fn(struct dma_chan *chan, void *node) > +{ > + struct epf_dma_filter *filter = node; > + struct dma_slave_caps caps; > + > + memset(&caps, 0, sizeof(caps)); > + dma_get_slave_caps(chan, &caps); > + > + return chan->device->dev == filter->dev > + && (filter->dma_mask & caps.directions); > +} > + > /** > * pci_epf_test_init_dma_chan() - Function to initialize EPF test DMA channel > * @epf_test: the EPF test device that performs data transfer operation > @@ -158,10 +195,44 @@ 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 epf_dma_filter filter; > struct dma_chan *dma_chan; > dma_cap_mask_t mask; > int ret; > > + filter.dev = epf->epc->dev.parent; > + filter.dma_mask = BIT(DMA_DEV_TO_MEM); > + > + dma_cap_zero(mask); > + dma_cap_set(DMA_SLAVE, mask); > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > + if (IS_ERR_OR_NULL(dma_chan)) { > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); > + goto fail_back_tx; > + } > + > + epf_test->dma_chan_rx = dma_chan; > + > + filter.dma_mask = BIT(DMA_MEM_TO_DEV); > + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); > + > + if (IS_ERR(dma_chan)) { > + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); > + goto fail_back_rx; > + } > + > + epf_test->dma_chan_tx = dma_chan; > + epf_test->dma_private = true; > + > + init_completion(&epf_test->transfer_complete); > + > + return 0; > + > +fail_back_rx: > + dma_release_channel(epf_test->dma_chan_rx); > + epf_test->dma_chan_tx = NULL; > + > +fail_back_tx: > dma_cap_zero(mask); > dma_cap_set(DMA_MEMCPY, mask); > > @@ -174,7 +245,7 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test) > } > init_completion(&epf_test->transfer_complete); > > - epf_test->dma_chan = dma_chan; > + epf_test->dma_chan_tx = epf_test->dma_chan_rx = dma_chan; > > return 0; > } > @@ -190,8 +261,17 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test) > if (!epf_test->dma_supported) > return; > > - dma_release_channel(epf_test->dma_chan); > - epf_test->dma_chan = NULL; > + dma_release_channel(epf_test->dma_chan_tx); > + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { > + epf_test->dma_chan_tx = NULL; > + epf_test->dma_chan_rx = NULL; > + return; > + } > + > + dma_release_channel(epf_test->dma_chan_rx); > + epf_test->dma_chan_rx = NULL; > + > + return; > } > > static void pci_epf_test_print_rate(const char *ops, u64 size, > @@ -280,8 +360,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test) > goto err_map_addr; > } > > + if (epf_test->dma_private) { > + 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); > + src_phys_addr, reg->size, 0, DMA_MEM_TO_MEM); > if (ret) > dev_err(dev, "Data transfer failed\n"); > } else { > @@ -363,7 +449,8 @@ 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); > + phys_addr, reg->size, > + reg->src_addr, DMA_DEV_TO_MEM); > if (ret) > dev_err(dev, "Data transfer failed\n"); > ktime_get_ts64(&end); > @@ -453,8 +540,9 @@ 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); > + src_phys_addr, reg->size, reg->dst_addr, DMA_MEM_TO_DEV); > if (ret) > dev_err(dev, "Data transfer failed\n"); > ktime_get_ts64(&end);
diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c index 90d84d3bc868f..f26afd02f3a86 100644 --- a/drivers/pci/endpoint/functions/pci-epf-test.c +++ b/drivers/pci/endpoint/functions/pci-epf-test.c @@ -52,9 +52,11 @@ struct pci_epf_test { enum pci_barno test_reg_bar; size_t msix_table_offset; struct delayed_work cmd_handler; - struct dma_chan *dma_chan; + struct dma_chan *dma_chan_tx; + struct dma_chan *dma_chan_rx; struct completion transfer_complete; bool dma_supported; + bool dma_private; const struct pci_epc_features *epc_features; }; @@ -105,12 +107,15 @@ static void pci_epf_test_dma_callback(void *param) */ 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) + size_t len, dma_addr_t dma_remote, + enum dma_transfer_direction dir) { + struct dma_chan *chan = (dir == DMA_DEV_TO_MEM) ? epf_test->dma_chan_tx : epf_test->dma_chan_rx; + dma_addr_t dma_local = (dir == DMA_MEM_TO_DEV) ? dma_src : dma_dst; 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 dma_slave_config sconf = {}; struct device *dev = &epf->dev; dma_cookie_t cookie; int ret; @@ -120,7 +125,22 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, return -EINVAL; } - tx = dmaengine_prep_dma_memcpy(chan, dma_dst, dma_src, len, flags); + if (epf_test->dma_private) { + sconf.direction = dir; + if (dir == DMA_MEM_TO_DEV) + sconf.dst_addr = dma_remote; + else + sconf.src_addr = dma_remote; + + if (dmaengine_slave_config(chan, &sconf)) { + dev_err(dev, "DMA slave config fail\n"); + return -EIO; + } + tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags); + } else { + 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; @@ -148,6 +168,23 @@ static int pci_epf_test_data_transfer(struct pci_epf_test *epf_test, return 0; } +struct epf_dma_filter { + struct device *dev; + u32 dma_mask; +}; + +static bool epf_dma_filter_fn(struct dma_chan *chan, void *node) +{ + struct epf_dma_filter *filter = node; + struct dma_slave_caps caps; + + memset(&caps, 0, sizeof(caps)); + dma_get_slave_caps(chan, &caps); + + return chan->device->dev == filter->dev + && (filter->dma_mask & caps.directions); +} + /** * pci_epf_test_init_dma_chan() - Function to initialize EPF test DMA channel * @epf_test: the EPF test device that performs data transfer operation @@ -158,10 +195,44 @@ 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 epf_dma_filter filter; struct dma_chan *dma_chan; dma_cap_mask_t mask; int ret; + filter.dev = epf->epc->dev.parent; + filter.dma_mask = BIT(DMA_DEV_TO_MEM); + + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); + if (IS_ERR_OR_NULL(dma_chan)) { + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); + goto fail_back_tx; + } + + epf_test->dma_chan_rx = dma_chan; + + filter.dma_mask = BIT(DMA_MEM_TO_DEV); + dma_chan = dma_request_channel(mask, epf_dma_filter_fn, &filter); + + if (IS_ERR(dma_chan)) { + dev_info(dev, "Failed to get private DMA channel. Falling back to generic one\n"); + goto fail_back_rx; + } + + epf_test->dma_chan_tx = dma_chan; + epf_test->dma_private = true; + + init_completion(&epf_test->transfer_complete); + + return 0; + +fail_back_rx: + dma_release_channel(epf_test->dma_chan_rx); + epf_test->dma_chan_tx = NULL; + +fail_back_tx: dma_cap_zero(mask); dma_cap_set(DMA_MEMCPY, mask); @@ -174,7 +245,7 @@ static int pci_epf_test_init_dma_chan(struct pci_epf_test *epf_test) } init_completion(&epf_test->transfer_complete); - epf_test->dma_chan = dma_chan; + epf_test->dma_chan_tx = epf_test->dma_chan_rx = dma_chan; return 0; } @@ -190,8 +261,17 @@ static void pci_epf_test_clean_dma_chan(struct pci_epf_test *epf_test) if (!epf_test->dma_supported) return; - dma_release_channel(epf_test->dma_chan); - epf_test->dma_chan = NULL; + dma_release_channel(epf_test->dma_chan_tx); + if (epf_test->dma_chan_tx == epf_test->dma_chan_rx) { + epf_test->dma_chan_tx = NULL; + epf_test->dma_chan_rx = NULL; + return; + } + + dma_release_channel(epf_test->dma_chan_rx); + epf_test->dma_chan_rx = NULL; + + return; } static void pci_epf_test_print_rate(const char *ops, u64 size, @@ -280,8 +360,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test) goto err_map_addr; } + if (epf_test->dma_private) { + 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); + src_phys_addr, reg->size, 0, DMA_MEM_TO_MEM); if (ret) dev_err(dev, "Data transfer failed\n"); } else { @@ -363,7 +449,8 @@ 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); + phys_addr, reg->size, + reg->src_addr, DMA_DEV_TO_MEM); if (ret) dev_err(dev, "Data transfer failed\n"); ktime_get_ts64(&end); @@ -453,8 +540,9 @@ 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); + src_phys_addr, reg->size, reg->dst_addr, DMA_MEM_TO_DEV); if (ret) dev_err(dev, "Data transfer failed\n"); ktime_get_ts64(&end);