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/genalloc.h>
  20 #include <linux/usb.h>
  21 #include <linux/usb/hcd.h>
  22
  23
  24 /*
  25  * DMA-Coherent Buffers
  26  */
  27
  28 /* FIXME tune these based on pool statistics ... */
  29 static size_t pool_max[HCD_BUFFER_POOLS] = {
  30         32, 128, 512, 2048,
  31 };
  32
  33 void __init usb_init_pool_max(void)
  34 {
  35         /*
  36          * The pool_max values must never be smaller than
  37          * ARCH_DMA_MINALIGN.
  38          */
  39         if (ARCH_DMA_MINALIGN <= 32)
  40                 ;                       /* Original value is okay */
  41         else if (ARCH_DMA_MINALIGN <= 64)
  42                 pool_max[0] = 64;
  43         else if (ARCH_DMA_MINALIGN <= 128)
  44                 pool_max[0] = 0;        /* Don't use this pool */
  45         else
  46                 BUILD_BUG();            /* We don't allow this */
  47 }
  48
  49 /* SETUP primitives */
  50
  51 /**
  52  * hcd_buffer_create - initialize buffer pools
  53  * @hcd: the bus whose buffer pools are to be initialized
  54  *
  55  * Context: task context, might sleep
  56  *
  57  * Call this as part of initializing a host controller that uses the dma
  58  * memory allocators.  It initializes some pools of dma-coherent memory that
  59  * will be shared by all drivers using that controller.
  60  *
  61  * Call hcd_buffer_destroy() to clean up after using those pools.
  62  *
  63  * Return: 0 if successful. A negative errno value otherwise.
  64  */
  65 int hcd_buffer_create(struct usb_hcd *hcd)
  66 {
  67         char            name[16];
  68         int             i, size;
  69
  70         if (hcd->localmem_pool || !hcd_uses_dma(hcd))
  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  *
  93  * Context: task context, might sleep
  94  *
  95  * This frees the buffer pools created by hcd_buffer_create().
  96  */
  97 void hcd_buffer_destroy(struct usb_hcd *hcd)
  98 {
  99         int i;
 100
 101         if (!IS_ENABLED(CONFIG_HAS_DMA))
 102                 return;
 103
 104         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 105                 dma_pool_destroy(hcd->pool[i]);
 106                 hcd->pool[i] = NULL;
 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
 115 void *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         if (size == 0)
 126                 return NULL;
 127
 128         if (hcd->localmem_pool)
 129                 return gen_pool_dma_alloc(hcd->localmem_pool, size, dma);
 130
 131         /* some USB hosts just use PIO */
 132         if (!hcd_uses_dma(hcd)) {
 133                 *dma = ~(dma_addr_t) 0;
 134                 return kmalloc(size, mem_flags);
 135         }
 136
 137         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 138                 if (size <= pool_max[i])
 139                         return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
 140         }
 141         return dma_alloc_coherent(hcd->self.sysdev, size, dma, mem_flags);
 142 }
 143
 144 void hcd_buffer_free(
 145         struct usb_bus          *bus,
 146         size_t                  size,
 147         void                    *addr,
 148         dma_addr_t              dma
 149 )
 150 {
 151         struct usb_hcd          *hcd = bus_to_hcd(bus);
 152         int                     i;
 153
 154         if (!addr)
 155                 return;
 156
 157         if (hcd->localmem_pool) {
 158                 gen_pool_free(hcd->localmem_pool, (unsigned long)addr, size);
 159                 return;
 160         }
 161
 162         if (!hcd_uses_dma(hcd)) {
 163                 kfree(addr);
 164                 return;
 165         }
 166
 167         for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 168                 if (size <= pool_max[i]) {
 169                         dma_pool_free(hcd->pool[i], addr, dma);
 170                         return;
 171                 }
 172         }
 173         dma_free_coherent(hcd->self.sysdev, size, addr, dma);
 174 }
 175
 176 void *hcd_buffer_alloc_pages(struct usb_hcd *hcd,
 177                 size_t size, gfp_t mem_flags, dma_addr_t *dma)
 178 {
 179         if (size == 0)
 180                 return NULL;
 181
 182         if (hcd->localmem_pool)
 183                 return gen_pool_dma_alloc_align(hcd->localmem_pool,
 184                                 size, dma, PAGE_SIZE);
 185
 186         /* some USB hosts just use PIO */
 187         if (!hcd_uses_dma(hcd)) {
 188                 *dma = DMA_MAPPING_ERROR;
 189                 return (void *)__get_free_pages(mem_flags,
 190                                 get_order(size));
 191         }
 192
 193         return dma_alloc_coherent(hcd->self.sysdev,
 194                         size, dma, mem_flags);
 195 }
 196
 197 void hcd_buffer_free_pages(struct usb_hcd *hcd,
 198                 size_t size, void *addr, dma_addr_t dma)
 199 {
 200         if (!addr)
 201                 return;
 202
 203         if (hcd->localmem_pool) {
 204                 gen_pool_free(hcd->localmem_pool,
 205                                 (unsigned long)addr, size);
 206                 return;
 207         }
 208
 209         if (!hcd_uses_dma(hcd)) {
 210                 free_pages((unsigned long)addr, get_order(size));
 211                 return;
 212         }
 213
 214         dma_free_coherent(hcd->self.sysdev, size, addr, dma);
 215 }