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                 dma_pool_destroy(hcd->pool[i]);
 105                 hcd->pool[i] = NULL;
 106         }
 107 }
 108
 109
 110 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
 111  * better sharing and to leverage mm/slab.c intelligence.
 112  */
 113
 114 void *hcd_buffer_alloc(
 115         struct usb_bus          *bus,
 116         size_t                  size,
 117         gfp_t                   mem_flags,
 118         dma_addr_t              *dma
 119 )
 120 {
 121         struct usb_hcd          *hcd = bus_to_hcd(bus);
 122         int                     i;
 123
 124         if (size == 0)
 125                 return NULL;
 126
 127         /* some USB hosts just use PIO */
 128         if (!IS_ENABLED(CONFIG_HAS_DMA) ||
 129             (!is_device_dma_capable(bus->sysdev) &&
 130              !(hcd->driver->flags & HCD_LOCAL_MEM))) {
 131                 *dma = ~(dma_addr_t) 0;
 132                 return kmalloc(size, mem_flags);
 133         }
 134
 135         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 136                 if (size <= pool_max[i])
 137                         return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
 138         }
 139         return dma_alloc_coherent(hcd->self.sysdev, size, dma, mem_flags);
 140 }
 141
 142 void hcd_buffer_free(
 143         struct usb_bus          *bus,
 144         size_t                  size,
 145         void                    *addr,
 146         dma_addr_t              dma
 147 )
 148 {
 149         struct usb_hcd          *hcd = bus_to_hcd(bus);
 150         int                     i;
 151
 152         if (!addr)
 153                 return;
 154
 155         if (!IS_ENABLED(CONFIG_HAS_DMA) ||
 156             (!is_device_dma_capable(bus->sysdev) &&
 157              !(hcd->driver->flags & HCD_LOCAL_MEM))) {
 158                 kfree(addr);
 159                 return;
 160         }
 161
 162         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 163                 if (size <= pool_max[i]) {
 164                         dma_pool_free(hcd->pool[i], addr, dma);
 165                         return;
 166                 }
 167         }
 168         dma_free_coherent(hcd->self.sysdev, size, addr, dma);
 169 }