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