When trying to allocate space for an endpoint function on a BAR with a
fixed size, the size saved in the 'struct pci_epf_bar' should be the fixed
size. This is expected by pci_epc_set_bar().
However, if the fixed_size is smaller that the alignment, the size saved
in the 'struct pci_epf_bar' matches the alignment and it is a problem for
pci_epc_set_bar().
To solve this, continue to allocate space that match the iATU alignment
requirement, saving it as .aligned_size, then save the size that matches
what is present in the BAR.
Fixes: 2a9a801620ef ("PCI: endpoint: Add support to specify alignment for buffers allocated to BARs")
Reviewed-by: Niklas Cassel <cassel@xxxxxxxxxx>
Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
---
drivers/pci/endpoint/pci-epf-core.c | 21 ++++++++++++++-------
include/linux/pci-epf.h | 3 +++
2 files changed, 17 insertions(+), 7 deletions(-)
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index 394395c7f8decfa2010469655a4bd58a002993fd..982db6c1fbe77653f6a74a31df5c4e997507d2d8 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -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 +286,17 @@ 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 +307,7 @@ 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 +316,7 @@ 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;
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index 879d19cebd4fc6d8df9d724e3a52fa7fbd61e535..749cee0bcf2cc0600ad3be1582b0c497c5a21bed 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -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;
};
--
2.47.2
