LXR linux/drivers/usb/core/buffer.c

   1/*
   2 * DMA memory management for framework level HCD code (hc_driver)
   3 *
   4 * This implementation plugs in through generic "usb_bus" level methods,
   5 * and should work with all USB controllers, regardless of bus type.
   6 *
   7 * Released under the GPLv2 only.
   8 * SPDX-License-Identifier: GPL-2.0
   9 */
  10
  11#include <linux/module.h>
  12#include <linux/kernel.h>
  13#include <linux/slab.h>
  14#include <linux/device.h>
  15#include <linux/mm.h>
  16#include <linux/io.h>
  17#include <linux/dma-mapping.h>
  18#include <linux/dmapool.h>
  19#include <linux/usb.h>
  20#include <linux/usb/hcd.h>
  21
  22
  23/*
  24 * DMA-Coherent Buffers
  25 */
  26
  27/* FIXME tune these based on pool statistics ... */
  28static size_t pool_max[HCD_BUFFER_POOLS] = {
  29        32, 128, 512, 2048,
  30};
  31
  32void __init usb_init_pool_max(void)
  33{
  34        /*
  35         * The pool_max values must never be smaller than
  36         * ARCH_KMALLOC_MINALIGN.
  37         */
  38        if (ARCH_KMALLOC_MINALIGN <= 32)
  39                ;                       /* Original value is okay */
  40        else if (ARCH_KMALLOC_MINALIGN <= 64)
  41                pool_max[0] = 64;
  42        else if (ARCH_KMALLOC_MINALIGN <= 128)
  43                pool_max[0] = 0;        /* Don't use this pool */
  44        else
  45                BUILD_BUG();            /* We don't allow this */
  46}
  47
  48/* SETUP primitives */
  49
  50/**
  51 * hcd_buffer_create - initialize buffer pools
  52 * @hcd: the bus whose buffer pools are to be initialized
  53 * Context: !in_interrupt()
  54 *
  55 * Call this as part of initializing a host controller that uses the dma
  56 * memory allocators.  It initializes some pools of dma-coherent memory that
  57 * will be shared by all drivers using that controller.
  58 *
  59 * Call hcd_buffer_destroy() to clean up after using those pools.
  60 *
  61 * Return: 0 if successful. A negative errno value otherwise.
  62 */
  63int hcd_buffer_create(struct usb_hcd *hcd)
  64{
  65        char            name[16];
  66        int             i, size;
  67
  68        if (!IS_ENABLED(CONFIG_HAS_DMA) ||
  69            (!is_device_dma_capable(hcd->self.sysdev) &&
  70             !(hcd->driver->flags & HCD_LOCAL_MEM)))
  71                return 0;
  72
  73        for (i = 0; i < HCD_BUFFER_POOLS; i++) {
  74                size = pool_max[i];
  75                if (!size)
  76                        continue;
  77                snprintf(name, sizeof(name), "buffer-%d", size);
  78                hcd->pool[i] = dma_pool_create(name, hcd->self.sysdev,
  79                                size, size, 0);
  80                if (!hcd->pool[i]) {
  81                        hcd_buffer_destroy(hcd);
  82                        return -ENOMEM;
  83                }
  84        }
  85        return 0;
  86}
  87
  88
  89/**
  90 * hcd_buffer_destroy - deallocate buffer pools
  91 * @hcd: the bus whose buffer pools are to be destroyed
  92 * Context: !in_interrupt()
  93 *
  94 * This frees the buffer pools created by hcd_buffer_create().
  95 */
  96void hcd_buffer_destroy(struct usb_hcd *hcd)
  97{
  98        int i;
  99
 100        if (!IS_ENABLED(CONFIG_HAS_DMA))
 101                return;
 102
 103        for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 104                struct dma_pool *pool = hcd->pool[i];
 105
 106                if (pool) {
 107                        dma_pool_destroy(pool);
 108                        hcd->pool[i] = NULL;
 109                }
 110        }
 111}
 112
 113
 114/* sometimes alloc/free could use kmalloc with GFP_DMA, for
 115 * better sharing and to leverage mm/slab.c intelligence.
 116 */
 117
 118void *hcd_buffer_alloc(
 119        struct usb_bus          *bus,
 120        size_t                  size,
 121        gfp_t                   mem_flags,
 122        dma_addr_t              *dma
 123)
 124{
 125        struct usb_hcd          *hcd = bus_to_hcd(bus);
 126        int                     i;
 127
 128        if (size == 0)
 129                return NULL;
 130
 131        /* some USB hosts just use PIO */
 132        if (!IS_ENABLED(CONFIG_HAS_DMA) ||
 133            (!is_device_dma_capable(bus->sysdev) &&
 134             !(hcd->driver->flags & HCD_LOCAL_MEM))) {
 135                *dma = ~(dma_addr_t) 0;
 136                return kmalloc(size, mem_flags);
 137        }
 138
 139        for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 140                if (size <= pool_max[i])
 141                        return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
 142        }
 143        return dma_alloc_coherent(hcd->self.sysdev, size, dma, mem_flags);
 144}
 145
 146void hcd_buffer_free(
 147        struct usb_bus          *bus,
 148        size_t                  size,
 149        void                    *addr,
 150        dma_addr_t              dma
 151)
 152{
 153        struct usb_hcd          *hcd = bus_to_hcd(bus);
 154        int                     i;
 155
 156        if (!addr)
 157                return;
 158
 159        if (!IS_ENABLED(CONFIG_HAS_DMA) ||
 160            (!is_device_dma_capable(bus->sysdev) &&
 161             !(hcd->driver->flags & HCD_LOCAL_MEM))) {
 162                kfree(addr);
 163                return;
 164        }
 165
 166        for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 167                if (size <= pool_max[i]) {
 168                        dma_pool_free(hcd->pool[i], addr, dma);
 169                        return;
 170                }
 171        }
 172        dma_free_coherent(hcd->self.sysdev, size, addr, dma);
 173}
 174