linux/drivers/usb/core/buffer.c
Alan Stern 1720058343 usbcore: trim down usb_bus structure
As part of the ongoing program to flatten out the HCD bus-glue layer,
this patch (as771b) eliminates the hcpriv, release, and kref fields
from struct usb_bus.  hcpriv and release were not being used for
anything worthwhile, and kref has been moved into the enclosing
usb_hcd structure.

Along with those changes, the patch gets rid of usb_bus_get and
usb_bus_put, replacing them with usb_get_hcd and usb_put_hcd.

The one interesting aspect is that the dev_set_drvdata call was
removed from usb_put_hcd, where it clearly doesn't belong.  This means
the driver private data won't get reset to NULL.  It shouldn't cause
any problems, since the private data is undefined when no driver is
bound.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-09-27 11:58:56 -07:00

149 lines
3.1 KiB
C

/*
* 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, regardles of bus type.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <asm/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/usb.h>
#include "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, or returns a negative
* errno value on error.
*
* Call hcd_buffer_destroy() to clean up after using those pools.
*/
int hcd_buffer_create (struct usb_hcd *hcd)
{
char name [16];
int i, size;
if (!hcd->self.controller->dma_mask)
return 0;
for (i = 0; i < HCD_BUFFER_POOLS; i++) {
if (!(size = pool_max [i]))
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 SLAB_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) {
*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, 0);
}
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) {
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);
}