LXR linux/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 ... */
  29static size_t pool_max[HCD_BUFFER_POOLS] = {
  30        32, 128, 512, 2048,
  31};
  32
  33void __init usb_init_pool_max(void)
  34{
  35        /*
  36         * The pool_max values must never be smaller than
  37         * ARCH_KMALLOC_MINALIGN.
  38         */
  39        if (ARCH_KMALLOC_MINALIGN <= 32)
  40                ;                       /* Original value is okay */
  41        else if (ARCH_KMALLOC_MINALIGN <= 64)
  42                pool_max[0] = 64;
  43        else if (ARCH_KMALLOC_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 * Context: !in_interrupt()
  55 *
  56 * Call this as part of initializing a host controller that uses the dma
  57 * memory allocators.  It initializes some pools of dma-coherent memory that
  58 * will be shared by all drivers using that controller.
  59 *
  60 * Call hcd_buffer_destroy() to clean up after using those pools.
  61 *
  62 * Return: 0 if successful. A negative errno value otherwise.
  63 */
  64int hcd_buffer_create(struct usb_hcd *hcd)
  65{
  66        char            name[16];
  67        int             i, size;
  68
  69        if (hcd->localmem_pool || !hcd_uses_dma(hcd))
  70                return 0;
  71
  72        for (i = 0; i < HCD_BUFFER_POOLS; i++) {
  73                size = pool_max[i];
  74                if (!size)
  75                        continue;
  76                snprintf(name, sizeof(name), "buffer-%d", size);
  77                hcd->pool[i] = dma_pool_create(name, hcd->self.sysdev,
  78                                size, size, 0);
  79                if (!hcd->pool[i]) {
  80                        hcd_buffer_destroy(hcd);
  81                        return -ENOMEM;
  82                }
  83        }
  84        return 0;
  85}
  86
  87
  88/**
  89 * hcd_buffer_destroy - deallocate buffer pools
  90 * @hcd: the bus whose buffer pools are to be destroyed
  91 * Context: !in_interrupt()
  92 *
  93 * This frees the buffer pools created by hcd_buffer_create().
  94 */
  95void hcd_buffer_destroy(struct usb_hcd *hcd)
  96{
  97        int i;
  98
  99        if (!IS_ENABLED(CONFIG_HAS_DMA))
 100                return;
 101
 102        for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 103                dma_pool_destroy(hcd->pool[i]);
 104                hcd->pool[i] = NULL;
 105        }
 106}
 107
 108
 109/* sometimes alloc/free could use kmalloc with GFP_DMA, for
 110 * better sharing and to leverage mm/slab.c intelligence.
 111 */
 112
 113void *hcd_buffer_alloc(
 114        struct usb_bus          *bus,
 115        size_t                  size,
 116        gfp_t                   mem_flags,
 117        dma_addr_t              *dma
 118)
 119{
 120        struct usb_hcd          *hcd = bus_to_hcd(bus);
 121        int                     i;
 122
 123        if (size == 0)
 124                return NULL;
 125
 126        if (hcd->localmem_pool)
 127                return gen_pool_dma_alloc(hcd->localmem_pool, size, dma);
 128
 129        /* some USB hosts just use PIO */
 130        if (!hcd_uses_dma(hcd)) {
 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
 142void 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 (hcd->localmem_pool) {
 156                gen_pool_free(hcd->localmem_pool, (unsigned long)addr, size);
 157                return;
 158        }
 159
 160        if (!hcd_uses_dma(hcd)) {
 161                kfree(addr);
 162                return;
 163        }
 164
 165        for (i = 0; i < HCD_BUFFER_POOLS; i++) {
 166                if (size <= pool_max[i]) {
 167                        dma_pool_free(hcd->pool[i], addr, dma);
 168                        return;
 169                }
 170        }
 171        dma_free_coherent(hcd->self.sysdev, size, addr, dma);
 172}
 173