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| author | Niklas Cassel <cassel@kernel.org> | 2025-01-31 19:29:50 +0100 |
|---|---|---|
| committer | Krzysztof Wilczyński <kwilczynski@kernel.org> | 2025-03-08 14:43:02 +0000 |
| commit | 52132f3a63b33fd38ceef07392ed176db84d579f (patch) | |
| tree | 0a86c828d3f75d005bcf36aef9fbf04ad270b8db /drivers/pci | |
| parent | PCI: endpoint: pci-epf-test: Handle endianness properly (diff) | |
| download | linux-52132f3a63b33fd38ceef07392ed176db84d579f.tar.gz linux-52132f3a63b33fd38ceef07392ed176db84d579f.zip | |
PCI: endpoint: Allow EPF drivers to configure the size of Resizable BARs
A resizable BAR is different from a normal BAR in a few ways:
- The minimum size of a resizable BAR is 1 MB.
- Each BAR that is resizable has a Capability and Control register in
the Resizable BAR Capability structure.
These registers contain the supported sizes and the currently selected
size of a resizable BAR.
The supported sizes is a bitmap of the supported sizes. The selected size
is a single value that is equal to one of the supported sizes.
A resizable BAR thus has to be configured differently than a
BAR_PROGRAMMABLE BAR, which usually sets the BAR size/mask in a vendor
specific way.
The PCI endpoint framework currently does not support resizable BARs.
Add a BAR type BAR_RESIZABLE, so that an EPC driver can support resizable
BARs properly.
Note that the pci_epc_set_bar() API takes a struct pci_epf_bar which tells
the EPC driver how it wants to configure the BAR.
struct pci_epf_bar only has a single size struct member.
This means that an EPC driver will only be able to set a single supported
size. This is perfectly fine, as we do not need the complexity of allowing
a host to change the size of the BAR. If someone ever wants to support
resizing a resizable BAR, the pci_epc_set_bar() API can be extended in the
future.
With these changes, we allow an EPF driver to configure the size of
Resizable BARs, rather than forcing them to a 1 MB size.
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20250131182949.465530-10-cassel@kernel.org
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Diffstat (limited to 'drivers/pci')
| -rw-r--r-- | drivers/pci/endpoint/pci-epc-core.c | 4 | ||||
| -rw-r--r-- | drivers/pci/endpoint/pci-epf-core.c | 4 |
2 files changed, 8 insertions, 0 deletions
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c index 9e9ca5f8e8f8..10dfc716328e 100644 --- a/drivers/pci/endpoint/pci-epc-core.c +++ b/drivers/pci/endpoint/pci-epc-core.c @@ -609,6 +609,10 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, if (!epc_features) return -EINVAL; + if (epc_features->bar[bar].type == BAR_RESIZABLE && + (epf_bar->size < SZ_1M || (u64)epf_bar->size > (SZ_128G * 1024))) + return -EINVAL; + if (epc_features->bar[bar].type == BAR_FIXED && (epc_features->bar[bar].fixed_size != epf_bar->size)) return -EINVAL; diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c index 50bc2892a36c..394395c7f8de 100644 --- a/drivers/pci/endpoint/pci-epf-core.c +++ b/drivers/pci/endpoint/pci-epf-core.c @@ -274,6 +274,10 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar, if (size < 128) size = 128; + /* According to PCIe base spec, min size for a resizable BAR is 1 MB. */ + if (epc_features->bar[bar].type == BAR_RESIZABLE && size < SZ_1M) + size = SZ_1M; + if (epc_features->bar[bar].type == BAR_FIXED && bar_fixed_size) { if (size > bar_fixed_size) { dev_err(&epf->dev, |