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/config.h> 9 #include <linux/module.h> 10 #include <linux/kernel.h> 11 #include <linux/slab.h> 12 #include <linux/device.h> 13 #include <linux/mm.h> 14 #include <asm/io.h> 15 #include <asm/scatterlist.h> 16 #include <linux/dma-mapping.h> 17 #include <linux/dmapool.h> 18 #include <linux/usb.h> 19 #include "hcd.h" 20 21 22 /* 23 * DMA-Coherent Buffers 24 */ 25 26 /* FIXME tune these based on pool statistics ... */ 27 static const size_t pool_max [HCD_BUFFER_POOLS] = { 28 /* platforms without dma-friendly caches might need to 29 * prevent cacheline sharing... 30 */ 31 32, 32 128, 33 512, 34 PAGE_SIZE / 2 35 /* bigger --> allocate pages */ 36 }; 37 38 39 /* SETUP primitives */ 40 41 /** 42 * hcd_buffer_create - initialize buffer pools 43 * @hcd: the bus whose buffer pools are to be initialized 44 * Context: !in_interrupt() 45 * 46 * Call this as part of initializing a host controller that uses the dma 47 * memory allocators. It initializes some pools of dma-coherent memory that 48 * will be shared by all drivers using that controller, or returns a negative 49 * errno value on error. 50 * 51 * Call hcd_buffer_destroy() to clean up after using those pools. 52 */ 53 int hcd_buffer_create (struct usb_hcd *hcd) 54 { 55 char name [16]; 56 int i, size; 57 58 if (!hcd->self.controller->dma_mask) 59 return 0; 60 61 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 62 if (!(size = pool_max [i])) 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 SLAB_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->hcpriv; 109 int i; 110 111 /* some USB hosts just use PIO */ 112 if (!bus->controller->dma_mask) { 113 *dma = ~(dma_addr_t) 0; 114 return kmalloc (size, mem_flags); 115 } 116 117 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 118 if (size <= pool_max [i]) 119 return dma_pool_alloc (hcd->pool [i], mem_flags, dma); 120 } 121 return dma_alloc_coherent (hcd->self.controller, size, dma, 0); 122 } 123 124 void hcd_buffer_free ( 125 struct usb_bus *bus, 126 size_t size, 127 void *addr, 128 dma_addr_t dma 129 ) 130 { 131 struct usb_hcd *hcd = bus->hcpriv; 132 int i; 133 134 if (!addr) 135 return; 136 137 if (!bus->controller->dma_mask) { 138 kfree (addr); 139 return; 140 } 141 142 for (i = 0; i < HCD_BUFFER_POOLS; i++) { 143 if (size <= pool_max [i]) { 144 dma_pool_free (hcd->pool [i], addr, dma); 145 return; 146 } 147 } 148 dma_free_coherent (hcd->self.controller, size, addr, dma); 149 } 150