1 /* 2 * DMA memory management for framework level HCD code (hc_driver) 3 * 4 * This implementation plugs in through generic "usb_bus" level methods, 5 * and should work with all USB controllers, regardless of bus type. 6 */ 7 8 #include <linux/module.h> 9 #include <linux/kernel.h> 10 #include <linux/slab.h> 11 #include <linux/device.h> 12 #include <linux/mm.h> 13 #include <linux/io.h> 14 #include <linux/dma-mapping.h> 15 #include <linux/dmapool.h> 16 #include <linux/usb.h> 17 #include <linux/usb/hcd.h> 18 19 20 /* 21 * DMA-Coherent Buffers 22 */ 23 24 /* FIXME tune these based on pool statistics ... */ 25 static const size_t pool_max[HCD_BUFFER_POOLS] = { 26 /* platforms without dma-friendly caches might need to 27 * prevent cacheline sharing... 28 */ 29 32, 30 128, 31 512, 32 PAGE_SIZE / 2 33 /* bigger --> allocate pages */ 34 }; 35 36 37 /* SETUP primitives */ 38 39 /** 40 * hcd_buffer_create - initialize buffer pools 41 * @hcd: the bus whose buffer pools are to be initialized 42 * Context: !in_interrupt() 43 * 44 * Call this as part of initializing a host controller that uses the dma 45 * memory allocators. It initializes some pools of dma-coherent memory that 46 * will be shared by all drivers using that controller. 47 * 48 * Call hcd_buffer_destroy() to clean up after using those pools. 49 * 50 * Return: 0 if successful. A negative errno value otherwise. 51 */ 52 int hcd_buffer_create(struct usb_hcd *hcd) 53 { 54 char name[16]; 55 int i, size; 56 57 if (!hcd->self.controller->dma_mask && 58 !(hcd->driver->flags & HCD_LOCAL_MEM)) 59 return 0; 60 61 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 62 size = pool_max[i]; 63 if (!size) 64 continue; 65 snprintf(name, sizeof name, "buffer-%d", size); 66 hcd->pool[i] = dma_pool_create(name, hcd->self.controller, 67 size, size, 0); 68 if (!hcd->pool[i]) { 69 hcd_buffer_destroy(hcd); 70 return -ENOMEM; 71 } 72 } 73 return 0; 74 } 75 76 77 /** 78 * hcd_buffer_destroy - deallocate buffer pools 79 * @hcd: the bus whose buffer pools are to be destroyed 80 * Context: !in_interrupt() 81 * 82 * This frees the buffer pools created by hcd_buffer_create(). 83 */ 84 void hcd_buffer_destroy(struct usb_hcd *hcd) 85 { 86 int i; 87 88 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 89 struct dma_pool *pool = hcd->pool[i]; 90 if (pool) { 91 dma_pool_destroy(pool); 92 hcd->pool[i] = NULL; 93 } 94 } 95 } 96 97 98 /* sometimes alloc/free could use kmalloc with GFP_DMA, for 99 * better sharing and to leverage mm/slab.c intelligence. 100 */ 101 102 void *hcd_buffer_alloc( 103 struct usb_bus *bus, 104 size_t size, 105 gfp_t mem_flags, 106 dma_addr_t *dma 107 ) 108 { 109 struct usb_hcd *hcd = bus_to_hcd(bus); 110 int i; 111 112 /* some USB hosts just use PIO */ 113 if (!bus->controller->dma_mask && 114 !(hcd->driver->flags & HCD_LOCAL_MEM)) { 115 *dma = ~(dma_addr_t) 0; 116 return kmalloc(size, mem_flags); 117 } 118 119 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 120 if (size <= pool_max[i]) 121 return dma_pool_alloc(hcd->pool[i], mem_flags, dma); 122 } 123 return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags); 124 } 125 126 void hcd_buffer_free( 127 struct usb_bus *bus, 128 size_t size, 129 void *addr, 130 dma_addr_t dma 131 ) 132 { 133 struct usb_hcd *hcd = bus_to_hcd(bus); 134 int i; 135 136 if (!addr) 137 return; 138 139 if (!bus->controller->dma_mask && 140 !(hcd->driver->flags & HCD_LOCAL_MEM)) { 141 kfree(addr); 142 return; 143 } 144 145 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 146 if (size <= pool_max[i]) { 147 dma_pool_free(hcd->pool[i], addr, dma); 148 return; 149 } 150 } 151 dma_free_coherent(hcd->self.controller, size, addr, dma); 152 } 153