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PCI: endpoint: Retain fixed-size BAR size as well as aligned size

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When allocating space for an endpoint function on a BAR with a fixed size,
the size saved in 'struct pci_epf_bar.size' should be the fixed size as
expected by pci_epc_set_bar().

However, if pci_epf_alloc_space() increased the allocation size to
accommodate iATU alignment requirements, it previously saved the larger
aligned size in .size, which broke pci_epc_set_bar().

To solve this, keep the fixed BAR size in .size and save the aligned size
in a new .aligned_size for use when deallocating it.

Fixes: 2a9a801620 ("PCI: endpoint: Add support to specify alignment for buffers allocated to BARs")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
[mani: commit message fixup]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[bhelgaas: more specific subject, commit log, wrap comment to match file]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Niklas Cassel <cassel@kernel.org>
Link: https://patch.msgid.link/20250424-pci-ep-size-alignment-v5-1-2d4ec2af23f5@baylibre.com
This commit is contained in:
Jerome Brunet
2025-04-24 10:34:04 +02:00
committed by Bjorn Helgaas
parent 0af2f6be1b
commit 793908d60b
2 changed files with 18 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/pci/endpoint/pci-epf-core.c
View File

@@ -236,12 +236,13 @@ void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar,
}
dev = epc->dev.parent;
dma_free_coherent(dev, epf_bar[bar].size, addr,
dma_free_coherent(dev, epf_bar[bar].aligned_size, addr,
epf_bar[bar].phys_addr);
epf_bar[bar].phys_addr = 0;
epf_bar[bar].addr = NULL;
epf_bar[bar].size = 0;
epf_bar[bar].aligned_size = 0;
epf_bar[bar].barno = 0;
epf_bar[bar].flags = 0;
}
@@ -264,7 +265,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
enum pci_epc_interface_type type)
{
u64 bar_fixed_size = epc_features->bar[bar].fixed_size;
size_t align = epc_features->align;
size_t aligned_size, align = epc_features->align;
struct pci_epf_bar *epf_bar;
dma_addr_t phys_addr;
struct pci_epc *epc;
@@ -285,12 +286,18 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
return NULL;
}
size = bar_fixed_size;
} else {
/* BAR size must be power of two */
size = roundup_pow_of_two(size);
}
if (align)
size = ALIGN(size, align);
else
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.
*/
aligned_size = align ? ALIGN(size, align) : size;
if (type == PRIMARY_INTERFACE) {
epc = epf->epc;
@@ -301,7 +308,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
}
dev = epc->dev.parent;
space = dma_alloc_coherent(dev, size, &phys_addr, GFP_KERNEL);
space = dma_alloc_coherent(dev, aligned_size, &phys_addr, GFP_KERNEL);
if (!space) {
dev_err(dev, "failed to allocate mem space\n");
return NULL;
@@ -310,6 +317,7 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
epf_bar[bar].phys_addr = phys_addr;
epf_bar[bar].addr = space;
epf_bar[bar].size = size;
epf_bar[bar].aligned_size = aligned_size;
epf_bar[bar].barno = bar;
if (upper_32_bits(size) || epc_features->bar[bar].only_64bit)
epf_bar[bar].flags |= PCI_BASE_ADDRESS_MEM_TYPE_64;

3
include/linux/pci-epf.h
View File

@@ -114,6 +114,8 @@ struct pci_epf_driver {
* @phys_addr: physical address that should be mapped to the BAR
* @addr: virtual address corresponding to the @phys_addr
* @size: the size of the address space present in BAR
* @aligned_size: the size actually allocated to accommodate the iATU alignment
* requirement
* @barno: BAR number
* @flags: flags that are set for the BAR
*/
@@ -121,6 +123,7 @@ struct pci_epf_bar {
dma_addr_t phys_addr;
void *addr;
size_t size;
size_t aligned_size;
enum pci_barno barno;
int flags;
};