2 * DMA memory management for framework level HCD code (hc_driver)
4 * This implementation plugs in through generic "usb_bus" level methods,
5 * and should work with all USB controllers, regardles of bus type.
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/slab.h>
11 #include <linux/device.h>
14 #include <asm/scatterlist.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/dmapool.h>
17 #include <linux/usb.h>
22 * DMA-Coherent Buffers
25 /* FIXME tune these based on pool statistics ... */
26 static const size_t pool_max [HCD_BUFFER_POOLS] = {
27 /* platforms without dma-friendly caches might need to
28 * prevent cacheline sharing...
34 /* bigger --> allocate pages */
38 /* SETUP primitives */
41 * hcd_buffer_create - initialize buffer pools
42 * @hcd: the bus whose buffer pools are to be initialized
43 * Context: !in_interrupt()
45 * Call this as part of initializing a host controller that uses the dma
46 * memory allocators. It initializes some pools of dma-coherent memory that
47 * will be shared by all drivers using that controller, or returns a negative
48 * errno value on error.
50 * Call hcd_buffer_destroy() to clean up after using those pools.
52 int hcd_buffer_create(struct usb_hcd *hcd)
57 if (!hcd->self.controller->dma_mask)
60 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
61 if (!(size = pool_max [i]))
63 snprintf(name, sizeof name, "buffer-%d", size);
64 hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
67 hcd_buffer_destroy(hcd);
76 * hcd_buffer_destroy - deallocate buffer pools
77 * @hcd: the bus whose buffer pools are to be destroyed
78 * Context: !in_interrupt()
80 * This frees the buffer pools created by hcd_buffer_create().
82 void hcd_buffer_destroy(struct usb_hcd *hcd)
86 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
87 struct dma_pool *pool = hcd->pool[i];
89 dma_pool_destroy(pool);
96 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
97 * better sharing and to leverage mm/slab.c intelligence.
100 void *hcd_buffer_alloc(
107 struct usb_hcd *hcd = bus_to_hcd(bus);
110 /* some USB hosts just use PIO */
111 if (!bus->controller->dma_mask) {
112 *dma = ~(dma_addr_t) 0;
113 return kmalloc(size, mem_flags);
116 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
117 if (size <= pool_max [i])
118 return dma_pool_alloc(hcd->pool [i], mem_flags, dma);
120 return dma_alloc_coherent(hcd->self.controller, size, dma, 0);
123 void hcd_buffer_free(
130 struct usb_hcd *hcd = bus_to_hcd(bus);
136 if (!bus->controller->dma_mask) {
141 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
142 if (size <= pool_max [i]) {
143 dma_pool_free(hcd->pool [i], addr, dma);
147 dma_free_coherent(hcd->self.controller, size, addr, dma);