| Message ID | 20250113102730.1700963-13-cassel@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Krzysztof Wilczyński |
| Headers | show |
| Series | PCI: endpoint: Add support for resizable BARs | expand |
On Mon, Jan 13, 2025 at 11:27:36AM +0100, Niklas Cassel wrote: > The support for a specific iATU alignment was added in > commit 2a9a801620ef ("PCI: endpoint: Add support to specify alignment for > buffers allocated to BARs"). > > This commit specifically mentions both that the alignment by each DWC > based EP driver should match CX_ATU_MIN_REGION_SIZE, and that AM65x > specifically has a 64 KB alignment. > > This also matches the CX_ATU_MIN_REGION_SIZE value specified by > "12.2.2.4.7 PCIe Subsystem Address Translation" in the AM65x TRM: > https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf > > This higher value, 1 MB, was obviously an ugly hack used to be able to > handle Resizable BARs which have a minimum size of 1 MB. > > Now when we actually have support for Resizable BARs, let's configure the > iATU alignment requirement to the actual requirement. > (BARs described as Resizable will still get aligned to 1 MB.) > > Signed-off-by: Niklas Cassel <cassel@kernel.org> This warrants a Fixes tag. But also add stable+noautosel@kernel.org to not backport this change without dependency. Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> - Mani > --- > drivers/pci/controller/dwc/pci-keystone.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c > index fdc610ec7e5e..76a37368ae4f 100644 > --- a/drivers/pci/controller/dwc/pci-keystone.c > +++ b/drivers/pci/controller/dwc/pci-keystone.c > @@ -970,7 +970,7 @@ static const struct pci_epc_features ks_pcie_am654_epc_features = { > .bar[BAR_3] = { .type = BAR_FIXED, .fixed_size = SZ_64K, }, > .bar[BAR_4] = { .type = BAR_FIXED, .fixed_size = 256, }, > .bar[BAR_5] = { .type = BAR_RESIZABLE, }, > - .align = SZ_1M, > + .align = SZ_64K, > }; > > static const struct pci_epc_features* > -- > 2.47.1 >
diff --git a/drivers/pci/controller/dwc/pci-keystone.c b/drivers/pci/controller/dwc/pci-keystone.c index fdc610ec7e5e..76a37368ae4f 100644 --- a/drivers/pci/controller/dwc/pci-keystone.c +++ b/drivers/pci/controller/dwc/pci-keystone.c @@ -970,7 +970,7 @@ static const struct pci_epc_features ks_pcie_am654_epc_features = { .bar[BAR_3] = { .type = BAR_FIXED, .fixed_size = SZ_64K, }, .bar[BAR_4] = { .type = BAR_FIXED, .fixed_size = 256, }, .bar[BAR_5] = { .type = BAR_RESIZABLE, }, - .align = SZ_1M, + .align = SZ_64K, }; static const struct pci_epc_features*
The support for a specific iATU alignment was added in commit 2a9a801620ef ("PCI: endpoint: Add support to specify alignment for buffers allocated to BARs"). This commit specifically mentions both that the alignment by each DWC based EP driver should match CX_ATU_MIN_REGION_SIZE, and that AM65x specifically has a 64 KB alignment. This also matches the CX_ATU_MIN_REGION_SIZE value specified by "12.2.2.4.7 PCIe Subsystem Address Translation" in the AM65x TRM: https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf This higher value, 1 MB, was obviously an ugly hack used to be able to handle Resizable BARs which have a minimum size of 1 MB. Now when we actually have support for Resizable BARs, let's configure the iATU alignment requirement to the actual requirement. (BARs described as Resizable will still get aligned to 1 MB.) Signed-off-by: Niklas Cassel <cassel@kernel.org> --- drivers/pci/controller/dwc/pci-keystone.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)