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/*
* DMA memory management for framework level HCD code (hc_driver)
*
* This implementation plugs in through generic "usb_bus" level methods,
* and should work with all USB controllers, regardless of bus type.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/mm.h>
#include <linux/io.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
/*
* DMA-Coherent Buffers
*/
/* FIXME tune these based on pool statistics ... */
static const size_t pool_max[HCD_BUFFER_POOLS] = {
/* platforms without dma-friendly caches might need to
* prevent cacheline sharing...
*/
32,
128,
512,
PAGE_SIZE / 2
/* bigger --> allocate pages */
};
/* SETUP primitives */
/**
* hcd_buffer_create - initialize buffer pools
* @hcd: the bus whose buffer pools are to be initialized
* Context: !in_interrupt()
*
* Call this as part of initializing a host controller that uses the dma
* memory allocators. It initializes some pools of dma-coherent memory that
* will be shared by all drivers using that controller.
*
* Call hcd_buffer_destroy() to clean up after using those pools.
*
* Return: 0 if successful. A negative errno value otherwise.
*/
int hcd_buffer_create(struct usb_hcd *hcd)
{
char name[16];
int i, size;
if (!hcd->self.controller->dma_mask &&
!(hcd->driver->flags & HCD_LOCAL_MEM))
return 0;
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
size = pool_max[i];
if (!size)
continue;
snprintf(name, sizeof name, "buffer-%d", size);
hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
size, size, 0);
if (!hcd->pool[i]) {
hcd_buffer_destroy(hcd);
return -ENOMEM;
}
}
return 0;
}
/**
* hcd_buffer_destroy - deallocate buffer pools
* @hcd: the bus whose buffer pools are to be destroyed
* Context: !in_interrupt()
*
* This frees the buffer pools created by hcd_buffer_create().
*/
void hcd_buffer_destroy(struct usb_hcd *hcd)
{
int i;
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
struct dma_pool *pool = hcd->pool[i];
if (pool) {
dma_pool_destroy(pool);
hcd->pool[i] = NULL;
}
}
}
/* sometimes alloc/free could use kmalloc with GFP_DMA, for
* better sharing and to leverage mm/slab.c intelligence.
*/
void *hcd_buffer_alloc(
struct usb_bus *bus,
size_t size,
gfp_t mem_flags,
dma_addr_t *dma
)
{
struct usb_hcd *hcd = bus_to_hcd(bus);
int i;
/* some USB hosts just use PIO */
if (!bus->controller->dma_mask &&
!(hcd->driver->flags & HCD_LOCAL_MEM)) {
*dma = ~(dma_addr_t) 0;
return kmalloc(size, mem_flags);
}
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
if (size <= pool_max[i])
return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
}
return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
}
void hcd_buffer_free(
struct usb_bus *bus,
size_t size,
void *addr,
dma_addr_t dma
)
{
struct usb_hcd *hcd = bus_to_hcd(bus);
int i;
if (!addr)
return;
if (!bus->controller->dma_mask &&
!(hcd->driver->flags & HCD_LOCAL_MEM)) {
kfree(addr);
return;
}
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
if (size <= pool_max[i]) {
dma_pool_free(hcd->pool[i], addr, dma);
return;
}
}
dma_free_coherent(hcd->self.controller, size, addr, dma);
}
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