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 ... */
  25 static size_t pool_max[HCD_BUFFER_POOLS] = {
  26         32, 128, 512, 2048,
  27 };
  28
  29 void __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  */
  60 int hcd_buffer_create(struct usb_hcd *hcd)
  61 {
  62         char            name[16];
  63         int             i, size;
  64
  65         if (!hcd->self.controller->dma_mask &&
  66             !(hcd->driver->flags & HCD_LOCAL_MEM))
  67                 return 0;
  68
  69         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
  70                 size = pool_max[i];
  71                 if (!size)
  72                         continue;
  73                 snprintf(name, sizeof(name), "buffer-%d", size);
  74                 hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
  75                                 size, size, 0);
  76                 if (!hcd->pool[i]) {
  77                         hcd_buffer_destroy(hcd);
  78                         return -ENOMEM;
  79                 }
  80         }
  81         return 0;
  82 }
  83
  84
  85 /**
  86  * hcd_buffer_destroy - deallocate buffer pools
  87  * @hcd: the bus whose buffer pools are to be destroyed
  88  * Context: !in_interrupt()
  89  *
  90  * This frees the buffer pools created by hcd_buffer_create().
  91  */
  92 void hcd_buffer_destroy(struct usb_hcd *hcd)
  93 {
  94         int i;
  95
  96         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
  97                 struct dma_pool *pool = hcd->pool[i];
  98
  99                 if (pool) {
 100                         dma_pool_destroy(pool);
 101                         hcd->pool[i] = NULL;
 102                 }
 103         }
 104 }
 105
 106
 107 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
 108  * better sharing and to leverage mm/slab.c intelligence.
 109  */
 110
 111 void *hcd_buffer_alloc(
 112         struct usb_bus          *bus,
 113         size_t                  size,
 114         gfp_t                   mem_flags,
 115         dma_addr_t              *dma
 116 )
 117 {
 118         struct usb_hcd          *hcd = bus_to_hcd(bus);
 119         int                     i;
 120
 121         /* some USB hosts just use PIO */
 122         if (!bus->controller->dma_mask &&
 123             !(hcd->driver->flags & HCD_LOCAL_MEM)) {
 124                 *dma = ~(dma_addr_t) 0;
 125                 return kmalloc(size, mem_flags);
 126         }
 127
 128         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 129                 if (size <= pool_max[i])
 130                         return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
 131         }
 132         return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
 133 }
 134
 135 void hcd_buffer_free(
 136         struct usb_bus          *bus,
 137         size_t                  size,
 138         void                    *addr,
 139         dma_addr_t              dma
 140 )
 141 {
 142         struct usb_hcd          *hcd = bus_to_hcd(bus);
 143         int                     i;
 144
 145         if (!addr)
 146                 return;
 147
 148         if (!bus->controller->dma_mask &&
 149             !(hcd->driver->flags & HCD_LOCAL_MEM)) {
 150                 kfree(addr);
 151                 return;
 152         }
 153
 154         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 155                 if (size <= pool_max[i]) {
 156                         dma_pool_free(hcd->pool[i], addr, dma);
 157                         return;
 158                 }
 159         }
 160         dma_free_coherent(hcd->self.controller, size, addr, dma);
 161 }