drivers/usb/core/buffer.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * DMA memory management for framework level HCD code (hc_driver)
   4  *
   5  * This implementation plugs in through generic "usb_bus" level methods,
   6  * and should work with all USB controllers, regardless of bus type.
   7  *
   8  * Released under the GPLv2 only.
   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 ... */
  28 static size_t pool_max[HCD_BUFFER_POOLS] = {
  29         32, 128, 512, 2048,
  30 };
  31
  32 void __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  */
  63 int 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  */
  96 void 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
 118 void *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
 146 void 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 }