diff options
| author | Niklas Cassel <cassel@kernel.org> | 2025-01-31 19:29:51 +0100 |
|---|---|---|
| committer | Krzysztof Wilczyński <kwilczynski@kernel.org> | 2025-03-08 14:43:05 +0000 |
| commit | 4eb208424c9c49dc3298a45e8db7cf43fdf15600 (patch) | |
| tree | 0ddc2da36e2d94442ea01f57066181033197b6dc | |
| parent | 52132f3a63b33fd38ceef07392ed176db84d579f (diff) | |
PCI: endpoint: Add pci_epc_bar_size_to_rebar_cap()
Add a helper function to convert a size to the representation used by the
Resizable BAR Capability Register.
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20250131182949.465530-11-cassel@kernel.org
[mani: squashed the change that added PCIe spec reference to comments
from https://lore.kernel.org/linux-pci/20250219171454.2903059-2-cassel@kernel.org]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
| -rw-r--r-- | drivers/pci/endpoint/pci-epc-core.c | 27 | ||||
| -rw-r--r-- | include/linux/pci-epc.h | 1 |
2 files changed, 28 insertions, 0 deletions
diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c index 10dfc716328e..88cb426d3aec 100644 --- a/drivers/pci/endpoint/pci-epc-core.c +++ b/drivers/pci/endpoint/pci-epc-core.c @@ -639,6 +639,33 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, EXPORT_SYMBOL_GPL(pci_epc_set_bar); /** + * pci_epc_bar_size_to_rebar_cap() - convert a size to the representation used + * by the Resizable BAR Capability Register + * @size: the size to convert + * @cap: where to store the result + * + * Returns 0 on success and a negative error code in case of error. + */ +int pci_epc_bar_size_to_rebar_cap(size_t size, u32 *cap) +{ + /* + * As per PCIe r6.0, sec 7.8.6.2, min size for a resizable BAR is 1 MB, + * thus disallow a requested BAR size smaller than 1 MB. + * Disallow a requested BAR size larger than 128 TB. + */ + if (size < SZ_1M || (u64)size > (SZ_128G * 1024)) + return -EINVAL; + + *cap = ilog2(size) - ilog2(SZ_1M); + + /* Sizes in REBAR_CAP start at BIT(4). */ + *cap = BIT(*cap + 4); + + return 0; +} +EXPORT_SYMBOL_GPL(pci_epc_bar_size_to_rebar_cap); + +/** * pci_epc_write_header() - write standard configuration header * @epc: the EPC device to which the configuration header should be written * @func_no: the physical endpoint function number in the EPC device diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index 91ce39dc0fd4..713348322dea 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -275,6 +275,7 @@ void pci_epc_remove_epf(struct pci_epc *epc, struct pci_epf *epf, enum pci_epc_interface_type type); int pci_epc_write_header(struct pci_epc *epc, u8 func_no, u8 vfunc_no, struct pci_epf_header *hdr); +int pci_epc_bar_size_to_rebar_cap(size_t size, u32 *cap); int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, struct pci_epf_bar *epf_bar); void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, |