linux/drivers/usb/core/buffer.c
Greg Kroah-Hartman aa1f3bb567 USB: core: move existing SPDX tags to top of the file
To match the rest of the kernel, the SPDX tags for the drivers/usb/core/
files are moved to the first line of the file.  This makes it more
obvious the tag is present as well as making it match the other 12k
files in the tree with this location.

It also uses // to match the "expected style" as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-03 10:12:26 +01:00

174 lines
3.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* 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.
*
* Released under the GPLv2 only.
*/
#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 size_t pool_max[HCD_BUFFER_POOLS] = {
32, 128, 512, 2048,
};
void __init usb_init_pool_max(void)
{
/*
* The pool_max values must never be smaller than
* ARCH_KMALLOC_MINALIGN.
*/
if (ARCH_KMALLOC_MINALIGN <= 32)
; /* Original value is okay */
else if (ARCH_KMALLOC_MINALIGN <= 64)
pool_max[0] = 64;
else if (ARCH_KMALLOC_MINALIGN <= 128)
pool_max[0] = 0; /* Don't use this pool */
else
BUILD_BUG(); /* We don't allow this */
}
/* 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 (!IS_ENABLED(CONFIG_HAS_DMA) ||
(!is_device_dma_capable(hcd->self.sysdev) &&
!(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.sysdev,
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;
if (!IS_ENABLED(CONFIG_HAS_DMA))
return;
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;
if (size == 0)
return NULL;
/* some USB hosts just use PIO */
if (!IS_ENABLED(CONFIG_HAS_DMA) ||
(!is_device_dma_capable(bus->sysdev) &&
!(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.sysdev, 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 (!IS_ENABLED(CONFIG_HAS_DMA) ||
(!is_device_dma_capable(bus->sysdev) &&
!(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.sysdev, size, addr, dma);
}