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_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 */ 64 int 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 */ 95 void 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 */ 112 113 void *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 } 141 142 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 (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