/* * 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. * SPDX-License-Identifier: GPL-2.0 */ #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) || (!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; 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) || (!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 (!IS_ENABLED(CONFIG_HAS_DMA) || (!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); }