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, regardles 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, or returns a negative 47 * errno value on error. 48 * 49 * Call hcd_buffer_destroy() to clean up after using those pools. 50 */ 51 int hcd_buffer_create(struct usb_hcd *hcd) 52 { 53 char name[16]; 54 int i, size; 55 56 if (!hcd->self.controller->dma_mask && 57 !(hcd->driver->flags & HCD_LOCAL_MEM)) 58 return 0; 59 60 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 61 size = pool_max[i]; 62 if (!size) 63 continue; 64 snprintf(name, sizeof name, "buffer-%d", size); 65 hcd->pool[i] = dma_pool_create(name, hcd->self.controller, 66 size, size, 0); 67 if (!hcd->pool[i]) { 68 hcd_buffer_destroy(hcd); 69 return -ENOMEM; 70 } 71 } 72 return 0; 73 } 74 75 76 /** 77 * hcd_buffer_destroy - deallocate buffer pools 78 * @hcd: the bus whose buffer pools are to be destroyed 79 * Context: !in_interrupt() 80 * 81 * This frees the buffer pools created by hcd_buffer_create(). 82 */ 83 void hcd_buffer_destroy(struct usb_hcd *hcd) 84 { 85 int i; 86 87 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 88 struct dma_pool *pool = hcd->pool[i]; 89 if (pool) { 90 dma_pool_destroy(pool); 91 hcd->pool[i] = NULL; 92 } 93 } 94 } 95 96 97 /* sometimes alloc/free could use kmalloc with GFP_DMA, for 98 * better sharing and to leverage mm/slab.c intelligence. 99 */ 100 101 void *hcd_buffer_alloc( 102 struct usb_bus *bus, 103 size_t size, 104 gfp_t mem_flags, 105 dma_addr_t *dma 106 ) 107 { 108 struct usb_hcd *hcd = bus_to_hcd(bus); 109 int i; 110 111 /* some USB hosts just use PIO */ 112 if (!bus->controller->dma_mask && 113 !(hcd->driver->flags & HCD_LOCAL_MEM)) { 114 *dma = ~(dma_addr_t) 0; 115 return kmalloc(size, mem_flags); 116 } 117 118 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 119 if (size <= pool_max[i]) 120 return dma_pool_alloc(hcd->pool[i], mem_flags, dma); 121 } 122 return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags); 123 } 124 125 void hcd_buffer_free( 126 struct usb_bus *bus, 127 size_t size, 128 void *addr, 129 dma_addr_t dma 130 ) 131 { 132 struct usb_hcd *hcd = bus_to_hcd(bus); 133 int i; 134 135 if (!addr) 136 return; 137 138 if (!bus->controller->dma_mask && 139 !(hcd->driver->flags & HCD_LOCAL_MEM)) { 140 kfree(addr); 141 return; 142 } 143 144 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 145 if (size <= pool_max[i]) { 146 dma_pool_free(hcd->pool[i], addr, dma); 147 return; 148 } 149 } 150 dma_free_coherent(hcd->self.controller, size, addr, dma); 151 } 152