diff options
Diffstat (limited to 'drivers/usb/core/buffer.c')
| -rw-r--r-- | drivers/usb/core/buffer.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c new file mode 100644 index 000000000..268ccbec8 --- /dev/null +++ b/drivers/usb/core/buffer.c @@ -0,0 +1,215 @@ +// 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: task context, might sleep + * + * 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: task context, might sleep + * + * 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); +} + +void *hcd_buffer_alloc_pages(struct usb_hcd *hcd, + size_t size, gfp_t mem_flags, dma_addr_t *dma) +{ + if (size == 0) + return NULL; + + if (hcd->localmem_pool) + return gen_pool_dma_alloc_align(hcd->localmem_pool, + size, dma, PAGE_SIZE); + + /* some USB hosts just use PIO */ + if (!hcd_uses_dma(hcd)) { + *dma = DMA_MAPPING_ERROR; + return (void *)__get_free_pages(mem_flags, + get_order(size)); + } + + return dma_alloc_coherent(hcd->self.sysdev, + size, dma, mem_flags); +} + +void hcd_buffer_free_pages(struct usb_hcd *hcd, + size_t size, void *addr, dma_addr_t dma) +{ + if (!addr) + return; + + if (hcd->localmem_pool) { + gen_pool_free(hcd->localmem_pool, + (unsigned long)addr, size); + return; + } + + if (!hcd_uses_dma(hcd)) { + free_pages((unsigned long)addr, get_order(size)); + return; + } + + dma_free_coherent(hcd->self.sysdev, size, addr, dma); +} |