linux/drivers/usb/core/buffer.c
Christoph Hellwig edfbcb321f usb: add a hcd_uses_dma helper
The USB buffer allocation code is the only place in the usb core (and in
fact the whole kernel) that uses is_device_dma_capable, while the URB
mapping code uses the uses_dma flag in struct usb_bus.  Switch the buffer
allocation to use the uses_dma flag used by the rest of the USB code,
and create a helper in hcd.h that checks this flag as well as the
CONFIG_HAS_DMA to simplify the caller a bit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20190811080520.21712-3-hch@lst.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-15 15:18:05 +02:00

173 lines
3.6 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/genalloc.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 (hcd->localmem_pool || !hcd_uses_dma(hcd))
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++) {
dma_pool_destroy(hcd->pool[i]);
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;
if (hcd->localmem_pool)
return gen_pool_dma_alloc(hcd->localmem_pool, size, dma);
/* some USB hosts just use PIO */
if (!hcd_uses_dma(hcd)) {
*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 (hcd->localmem_pool) {
gen_pool_free(hcd->localmem_pool, (unsigned long)addr, size);
return;
}
if (!hcd_uses_dma(hcd)) {
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);
}