| Message ID | 20220810183536.1630940-2-willmcvicker@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | PCI: dwc: Add support for 64-bit MSI target addresses | expand |
On Wed, Aug 10, 2022 at 06:35:34PM +0000, Will McVicker wrote: > Re-work the msi_msg DMA allocation logic to use dma_alloc_coherent() > which uses the coherent DMA mask to try and return an allocation within > the DMA mask limits. This allows kernel configurations that disable > ZONE_DMA32 to continue supporting a 32-bit DMA mask. Without this patch, > the PCIe host device will fail to probe when ZONE_DMA32 is disabled. > > Fixes: 35797e672ff0 ("PCI: dwc: Fix MSI msi_msg DMA mapping") > Reported-by: Isaac J. Manjarres <isaacmanjarres@google.com> > Signed-off-by: Will McVicker <willmcvicker@google.com> > --- > .../pci/controller/dwc/pcie-designware-host.c | 23 ++++++++----------- > 1 file changed, 9 insertions(+), 14 deletions(-) > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > index 7746f94a715f..8f2222f51671 100644 > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > @@ -272,9 +272,9 @@ static void dw_pcie_free_msi(struct dw_pcie_rp *pp) > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > struct device *dev = pci->dev; > > - dma_unmap_page(dev, pp->msi_data, PAGE_SIZE, DMA_FROM_DEVICE); > - if (pp->msi_page) > - __free_page(pp->msi_page); > + dma_free_coherent(dev, PAGE_SIZE, pp->msi_page, pp->msi_data); > + pp->msi_data = 0; > + pp->msi_page = NULL; > } > } > > @@ -375,22 +375,17 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp) > dw_chained_msi_isr, pp); > } > > - ret = dma_set_mask(dev, DMA_BIT_MASK(32)); > + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); > if (ret) > dev_warn(dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n"); > > - pp->msi_page = alloc_page(GFP_DMA32); > - pp->msi_data = dma_map_page(dev, pp->msi_page, 0, > - PAGE_SIZE, DMA_FROM_DEVICE); > - ret = dma_mapping_error(dev, pp->msi_data); > - if (ret) { > - dev_err(pci->dev, "Failed to map MSI data\n"); > - __free_page(pp->msi_page); > - pp->msi_page = NULL; > + pp->msi_page = dma_alloc_coherent(dev, PAGE_SIZE, &pp->msi_data, > + GFP_KERNEL); You can use the managed version, dmam_alloc_coherent(), and avoid the freeing yourself. Also with that, I think you don't need 'msi_page'? Also, no need to alloc a whole page. A u32 or u64? should be fine. The write never makes it to memory, so doesn't really matter. > + if (!pp->msi_page) { > + dev_err(dev, "Failed to alloc and map MSI data\n"); > pp->msi_data = 0; > dw_pcie_free_msi(pp); > - > - return ret; > + return -ENOMEM; > } > > return 0; > -- > 2.37.1.559.g78731f0fdb-goog >
On 08/10/2022, Rob Herring wrote: > On Wed, Aug 10, 2022 at 06:35:34PM +0000, Will McVicker wrote: > > Re-work the msi_msg DMA allocation logic to use dma_alloc_coherent() > > which uses the coherent DMA mask to try and return an allocation within > > the DMA mask limits. This allows kernel configurations that disable > > ZONE_DMA32 to continue supporting a 32-bit DMA mask. Without this patch, > > the PCIe host device will fail to probe when ZONE_DMA32 is disabled. > > > > Fixes: 35797e672ff0 ("PCI: dwc: Fix MSI msi_msg DMA mapping") > > Reported-by: Isaac J. Manjarres <isaacmanjarres@google.com> > > Signed-off-by: Will McVicker <willmcvicker@google.com> > > --- > > .../pci/controller/dwc/pcie-designware-host.c | 23 ++++++++----------- > > 1 file changed, 9 insertions(+), 14 deletions(-) > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > > index 7746f94a715f..8f2222f51671 100644 > > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > > @@ -272,9 +272,9 @@ static void dw_pcie_free_msi(struct dw_pcie_rp *pp) > > struct dw_pcie *pci = to_dw_pcie_from_pp(pp); > > struct device *dev = pci->dev; > > > > - dma_unmap_page(dev, pp->msi_data, PAGE_SIZE, DMA_FROM_DEVICE); > > - if (pp->msi_page) > > - __free_page(pp->msi_page); > > + dma_free_coherent(dev, PAGE_SIZE, pp->msi_page, pp->msi_data); > > + pp->msi_data = 0; > > + pp->msi_page = NULL; > > } > > } > > > > @@ -375,22 +375,17 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp) > > dw_chained_msi_isr, pp); > > } > > > > - ret = dma_set_mask(dev, DMA_BIT_MASK(32)); > > + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); > > if (ret) > > dev_warn(dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n"); > > > > - pp->msi_page = alloc_page(GFP_DMA32); > > - pp->msi_data = dma_map_page(dev, pp->msi_page, 0, > > - PAGE_SIZE, DMA_FROM_DEVICE); > > - ret = dma_mapping_error(dev, pp->msi_data); > > - if (ret) { > > - dev_err(pci->dev, "Failed to map MSI data\n"); > > - __free_page(pp->msi_page); > > - pp->msi_page = NULL; > > + pp->msi_page = dma_alloc_coherent(dev, PAGE_SIZE, &pp->msi_data, > > + GFP_KERNEL); > > You can use the managed version, dmam_alloc_coherent(), and avoid the > freeing yourself. Also with that, I think you don't need 'msi_page'? > > Also, no need to alloc a whole page. A u32 or u64? should be fine. The > write never makes it to memory, so doesn't really matter. > > > + if (!pp->msi_page) { > > + dev_err(dev, "Failed to alloc and map MSI data\n"); > > pp->msi_data = 0; > > dw_pcie_free_msi(pp); > > - > > - return ret; > > + return -ENOMEM; > > } > > > > return 0; > > -- > > 2.37.1.559.g78731f0fdb-goog > > Thanks for the review Rob! I've updated the series to address your concerns. Regards, Will
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c index 7746f94a715f..8f2222f51671 100644 --- a/drivers/pci/controller/dwc/pcie-designware-host.c +++ b/drivers/pci/controller/dwc/pcie-designware-host.c @@ -272,9 +272,9 @@ static void dw_pcie_free_msi(struct dw_pcie_rp *pp) struct dw_pcie *pci = to_dw_pcie_from_pp(pp); struct device *dev = pci->dev; - dma_unmap_page(dev, pp->msi_data, PAGE_SIZE, DMA_FROM_DEVICE); - if (pp->msi_page) - __free_page(pp->msi_page); + dma_free_coherent(dev, PAGE_SIZE, pp->msi_page, pp->msi_data); + pp->msi_data = 0; + pp->msi_page = NULL; } } @@ -375,22 +375,17 @@ static int dw_pcie_msi_host_init(struct dw_pcie_rp *pp) dw_chained_msi_isr, pp); } - ret = dma_set_mask(dev, DMA_BIT_MASK(32)); + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); if (ret) dev_warn(dev, "Failed to set DMA mask to 32-bit. Devices with only 32-bit MSI support may not work properly\n"); - pp->msi_page = alloc_page(GFP_DMA32); - pp->msi_data = dma_map_page(dev, pp->msi_page, 0, - PAGE_SIZE, DMA_FROM_DEVICE); - ret = dma_mapping_error(dev, pp->msi_data); - if (ret) { - dev_err(pci->dev, "Failed to map MSI data\n"); - __free_page(pp->msi_page); - pp->msi_page = NULL; + pp->msi_page = dma_alloc_coherent(dev, PAGE_SIZE, &pp->msi_data, + GFP_KERNEL); + if (!pp->msi_page) { + dev_err(dev, "Failed to alloc and map MSI data\n"); pp->msi_data = 0; dw_pcie_free_msi(pp); - - return ret; + return -ENOMEM; } return 0;
Re-work the msi_msg DMA allocation logic to use dma_alloc_coherent() which uses the coherent DMA mask to try and return an allocation within the DMA mask limits. This allows kernel configurations that disable ZONE_DMA32 to continue supporting a 32-bit DMA mask. Without this patch, the PCIe host device will fail to probe when ZONE_DMA32 is disabled. Fixes: 35797e672ff0 ("PCI: dwc: Fix MSI msi_msg DMA mapping") Reported-by: Isaac J. Manjarres <isaacmanjarres@google.com> Signed-off-by: Will McVicker <willmcvicker@google.com> --- .../pci/controller/dwc/pcie-designware-host.c | 23 ++++++++----------- 1 file changed, 9 insertions(+), 14 deletions(-)