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PCI: endpoint: Add pci_epf_get_required_bar_size() helper

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Introduce pci_epf_get_required_bar_size() helper to get the required BAR
size and backing memory size. This helper will be used to set a fixed MMIO
address as the backing memory for a BAR.

Since this helper returns both BAR size and the aligned memory size, use
two parameters, 'bar_size' and 'aligned_mem_size' to avoid confusion.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
[mani: renamed helper to pci_epf_get_required_bar_size(), reworded description]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Link: https://patch.msgid.link/20251015-vntb_msi_doorbell-v6-2-9230298b1910@nxp.com
This commit is contained in:
Frank Li
2025-10-15 11:27:29 -04:00
committed by Manivannan Sadhasivam
parent 483768846d
commit f71e2b67b5
1 changed files with 46 additions and 28 deletions
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74
drivers/pci/endpoint/pci-epf-core.c
View File

@@ -208,6 +208,48 @@ void pci_epf_remove_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf)
}
EXPORT_SYMBOL_GPL(pci_epf_remove_vepf);
static int pci_epf_get_required_bar_size(struct pci_epf *epf, size_t *bar_size,
size_t *aligned_mem_size,
enum pci_barno bar,
const struct pci_epc_features *epc_features,
enum pci_epc_interface_type type)
{
u64 bar_fixed_size = epc_features->bar[bar].fixed_size;
size_t align = epc_features->align;
size_t size = *bar_size;
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,
"requested BAR size is larger than fixed size\n");
return -ENOMEM;
}
size = bar_fixed_size;
} else {
/* BAR size must be power of two */
size = roundup_pow_of_two(size);
}
*bar_size = size;
/*
* The EPC's BAR start address must meet alignment requirements. In most
* cases, the alignment will match the BAR size. However, differences
* can occur—for example, when the fixed BAR size (e.g., 128 bytes) is
* smaller than the required alignment (e.g., 4 KB).
*/
*aligned_mem_size = align ? ALIGN(size, align) : size;
return 0;
}
/**
* pci_epf_free_space() - free the allocated PCI EPF register space
* @epf: the EPF device from whom to free the memory
@@ -264,40 +306,16 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
const struct pci_epc_features *epc_features,
enum pci_epc_interface_type type)
{
u64 bar_fixed_size = epc_features->bar[bar].fixed_size;
size_t mem_size, align = epc_features->align;
struct pci_epf_bar *epf_bar;
dma_addr_t phys_addr;
struct pci_epc *epc;
struct device *dev;
size_t mem_size;
void *space;
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,
"requested BAR size is larger than fixed size\n");
return NULL;
}
size = bar_fixed_size;
} else {
/* BAR size must be power of two */
size = roundup_pow_of_two(size);
}
/*
* Allocate enough memory to accommodate the iATU alignment
* requirement. In most cases, this will be the same as .size but
* it might be different if, for example, the fixed size of a BAR
* is smaller than align.
*/
mem_size = align ? ALIGN(size, align) : size;
if (pci_epf_get_required_bar_size(epf, &size, &mem_size, bar,
epc_features, type))
return NULL;
if (type == PRIMARY_INTERFACE) {
epc = epf->epc;