[PATCH v3 18/26] PCI: endpoint: Add support to allocate aligned buffers to be mapped in BARs

Kishon Vijay Abraham I
2019-03-25T09:43:46Z

Modify pci_epf_alloc_space API to take alignment size as argument in
order to argument in order to allocate aligned buffers to be mapped to
BARs.

Add 'align' parameter to epc_features which can be used by platform
drivers to specifiy the BAR allocation alignment requirements and use
this while invoking pci_epf_alloc_space.

This is mainly required for Synopsys Designware PCIe core which masks
the lower bits based on the BAR size (See "I/O and MEM Match Modes"
section in DesignWare Cores PCI Express Controller Databook version
4.90a).

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
drivers/pci/endpoint/functions/pci-epf-test.c | 5 +++--
drivers/pci/endpoint/pci-epf-core.c | 10 ++++++++--
include/linux/pci-epc.h | 2 ++
include/linux/pci-epf.h | 3 ++-
4 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index d0b91da49bf4..c0786ca74312 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -438,7 +438,7 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
epc_features = epf_test->epc_features;

base = pci_epf_alloc_space(epf, sizeof(struct pci_epf_test_reg),
- test_reg_bar);
+ test_reg_bar, epc_features->align);
if (!base) {
dev_err(dev, "Failed to allocated register space\n");
return -ENOMEM;
@@ -453,7 +453,8 @@ static int pci_epf_test_alloc_space(struct pci_epf *epf)
if (!!(epc_features->reserved_bar & (1 << bar)))
continue;

- base = pci_epf_alloc_space(epf, bar_size[bar], bar);
+ base = pci_epf_alloc_space(epf, bar_size[bar], bar,
+ epc_features->align);
if (!base)
dev_err(dev, "Failed to allocate space for BAR%d\n",
bar);
diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
index 8bfdcd291196..fb1306de8f40 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -109,10 +109,12 @@ EXPORT_SYMBOL_GPL(pci_epf_free_space);
* pci_epf_alloc_space() - allocate memory for the PCI EPF register space
* @size: the size of the memory that has to be allocated
* @bar: the BAR number corresponding to the allocated register space
+ * @align: alignment size for the allocation region
*
* Invoke to allocate memory for the PCI EPF register space.
*/
-void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar)
+void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
+ size_t align)
{
void *space;
struct device *dev = epf->epc->dev.parent;
@@ -120,7 +122,11 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar)

if (size < 128)
size = 128;
- size = roundup_pow_of_two(size);
+
+ if (align)
+ size = ALIGN(size, align);
+ else
+ size = roundup_pow_of_two(size);

space = dma_alloc_coherent(dev, size, &phys_addr, GFP_KERNEL);
if (!space) {
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index c3ffa3917f88..f641badc2c61 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -109,6 +109,7 @@ struct pci_epc {
* @reserved_bar: bitmap to indicate reserved BAR unavailable to function driver
* @bar_fixed_64bit: bitmap to indicate fixed 64bit BARs
* @bar_fixed_size: Array specifying the size supported by each BAR
+ * @align: alignment size required for BAR buffer allocation
*/
struct pci_epc_features {
unsigned int linkup_notifier : 1;
@@ -117,6 +118,7 @@ struct pci_epc_features {
u8 reserved_bar;
u8 bar_fixed_64bit;
u64 bar_fixed_size[BAR_5 + 1];
+ size_t align;
};

#define to_pci_epc(device) container_of((device), struct pci_epc, dev)
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index ec02f58758c8..2d6f07556682 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -149,7 +149,8 @@ void pci_epf_destroy(struct pci_epf *epf);
int __pci_epf_register_driver(struct pci_epf_driver *driver,
struct module *owner);
void pci_epf_unregister_driver(struct pci_epf_driver *driver);
-void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar);
+void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
+ size_t align);
void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar);
int pci_epf_bind(struct pci_epf *epf);
void pci_epf_unbind(struct pci_epf *epf);
--
2.17.1