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, regardless 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 <linux/dma-mapping.h>
15 #include <linux/dmapool.h>
16 #include <linux/usb.h>
17 #include <linux/usb/hcd.h>
21 * DMA-Coherent Buffers
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...
33 /* bigger --> allocate pages */
37 /* SETUP primitives */
40 * hcd_buffer_create - initialize buffer pools
41 * @hcd: the bus whose buffer pools are to be initialized
42 * Context: !in_interrupt()
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.
48 * Call hcd_buffer_destroy() to clean up after using those pools.
50 * Return: 0 if successful. A negative errno value otherwise.
52 int hcd_buffer_create(struct usb_hcd *hcd)
57 if (!hcd->self.controller->dma_mask &&
58 !(hcd->driver->flags & HCD_LOCAL_MEM))
61 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
65 snprintf(name, sizeof name, "buffer-%d", size);
66 hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
69 hcd_buffer_destroy(hcd);
78 * hcd_buffer_destroy - deallocate buffer pools
79 * @hcd: the bus whose buffer pools are to be destroyed
80 * Context: !in_interrupt()
82 * This frees the buffer pools created by hcd_buffer_create().
84 void hcd_buffer_destroy(struct usb_hcd *hcd)
88 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
89 struct dma_pool *pool = hcd->pool[i];
91 dma_pool_destroy(pool);
98 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
99 * better sharing and to leverage mm/slab.c intelligence.
102 void *hcd_buffer_alloc(
109 struct usb_hcd *hcd = bus_to_hcd(bus);
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);
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);
123 return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
126 void hcd_buffer_free(
133 struct usb_hcd *hcd = bus_to_hcd(bus);
139 if (!bus->controller->dma_mask &&
140 !(hcd->driver->flags & HCD_LOCAL_MEM)) {
145 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
146 if (size <= pool_max[i]) {
147 dma_pool_free(hcd->pool[i], addr, dma);
151 dma_free_coherent(hcd->self.controller, size, addr, dma);