[PATCH 04/18] PCI: endpoint: pci-epc-mem: Add support for configurable page size

Kishon Vijay Abraham I
2017-08-18T14:57:56Z

pci-epc-mem uses a page size equal to *PAGE_SIZE* (usually 4KB) to
manage the address space. However certain platforms like TI's K2G
has a restriction that this address space should be either divided
into 1MB/2MB/4MB or 8MB sizes (Ref: 11.14.4.9.1 Outbound Address
Translation in K2G TRM SPRUHY8F January 2016 – Revised May 2017).
Add support to handle different page sizes here.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
---
drivers/pci/endpoint/pci-epc-mem.c | 59 ++++++++++++++++++++++++++++++++------
include/linux/pci-epc.h | 8 +++++-
2 files changed, 57 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
index 3a94cc1caf22..83b7d5d3fc3e 100644
--- a/drivers/pci/endpoint/pci-epc-mem.c
+++ b/drivers/pci/endpoint/pci-epc-mem.c
@@ -24,21 +24,54 @@
#include <linux/pci-epc.h>

/**
- * pci_epc_mem_init() - initialize the pci_epc_mem structure
+ * pci_epc_mem_get_order() - determine the allocation order of a memory size
+ * @mem: address space of the endpoint controller
+ * @size: the size for which to get the order
+ *
+ * Reimplement get_order() for mem->page_size since the generic get_order
+ * always gets order with a constant PAGE_SIZE.
+ */
+static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
+{
+ int order;
+ unsigned int page_shift = ilog2(mem->page_size);
+
+ size--;
+ size >>= page_shift;
+#if BITS_PER_LONG == 32
+ order = fls(size);
+#else
+ order = fls64(size);
+#endif
+ return order;
+}
+
+/**
+ * __pci_epc_mem_init() - initialize the pci_epc_mem structure
* @epc: the EPC device that invoked pci_epc_mem_init
* @phys_base: the physical address of the base
* @size: the size of the address space
+ * @page_size: size of each page
*
* Invoke to initialize the pci_epc_mem structure used by the
* endpoint functions to allocate mapped PCI address.
*/
-int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size)
+int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
+ size_t page_size)
{
int ret;
struct pci_epc_mem *mem;
unsigned long *bitmap;
- int pages = size >> PAGE_SHIFT;
- int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
+ unsigned int page_shift;
+ int pages;
+ int bitmap_size;
+
+ if (page_size < PAGE_SIZE)
+ page_size = PAGE_SIZE;
+
+ page_shift = ilog2(page_size);
+ pages = size >> page_shift;
+ bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);

mem = kzalloc(sizeof(*mem), GFP_KERNEL);
if (!mem) {
@@ -54,6 +87,7 @@ int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size)

mem->bitmap = bitmap;
mem->phys_base = phys_base;
+ mem->page_size = page_size;
mem->pages = pages;
mem->size = size;

@@ -67,7 +101,7 @@ int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size)
err:
return ret;
}
-EXPORT_SYMBOL_GPL(pci_epc_mem_init);
+EXPORT_SYMBOL_GPL(__pci_epc_mem_init);

/**
* pci_epc_mem_exit() - cleanup the pci_epc_mem structure
@@ -101,13 +135,17 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
int pageno;
void __iomem *virt_addr;
struct pci_epc_mem *mem = epc->mem;
- int order = get_order(size);
+ unsigned int page_shift = ilog2(mem->page_size);
+ int order;
+
+ size = ALIGN(size, mem->page_size);
+ order = pci_epc_mem_get_order(mem, size);

pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
if (pageno < 0)
return NULL;

- *phys_addr = mem->phys_base + (pageno << PAGE_SHIFT);
+ *phys_addr = mem->phys_base + (pageno << page_shift);
virt_addr = ioremap(*phys_addr, size);
if (!virt_addr)
bitmap_release_region(mem->bitmap, pageno, order);
@@ -129,11 +167,14 @@ void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
void __iomem *virt_addr, size_t size)
{
int pageno;
- int order = get_order(size);
struct pci_epc_mem *mem = epc->mem;
+ unsigned int page_shift = ilog2(mem->page_size);
+ int order;

iounmap(virt_addr);
- pageno = (phys_addr - mem->phys_base) >> PAGE_SHIFT;
+ pageno = (phys_addr - mem->phys_base) >> page_shift;
+ size = ALIGN(size, mem->page_size);
+ order = pci_epc_mem_get_order(mem, size);
bitmap_release_region(mem->bitmap, pageno, order);
}
EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index af5edbf3eea3..f7a04e1af112 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -62,11 +62,13 @@ struct pci_epc_ops {
* @size: the size of the PCI address space
* @bitmap: bitmap to manage the PCI address space
* @pages: number of bits representing the address region
+ * @page_size: size of each page
*/
struct pci_epc_mem {
phys_addr_t phys_base;
size_t size;
unsigned long *bitmap;
+ size_t page_size;
int pages;
};

@@ -98,6 +100,9 @@ struct pci_epc {
#define devm_pci_epc_create(dev, ops) \
__devm_pci_epc_create((dev), (ops), THIS_MODULE)

+#define pci_epc_mem_init(epc, phys_addr, size) \
+ __pci_epc_mem_init((epc), (phys_addr), (size), PAGE_SIZE)
+
static inline void epc_set_drvdata(struct pci_epc *epc, void *data)
{
dev_set_drvdata(&epc->dev, data);
@@ -135,7 +140,8 @@ void pci_epc_stop(struct pci_epc *epc);
struct pci_epc *pci_epc_get(const char *epc_name);
void pci_epc_put(struct pci_epc *epc);

-int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_addr, size_t size);
+int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_addr, size_t size,
+ size_t page_size);
void pci_epc_mem_exit(struct pci_epc *epc);
void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
phys_addr_t *phys_addr, size_t size);
--
2.11.0