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 size_t pool_max[HCD_BUFFER_POOLS] = {
29 void __init usb_init_pool_max(void)
32 * The pool_max values must never be smaller than
33 * ARCH_KMALLOC_MINALIGN.
35 if (ARCH_KMALLOC_MINALIGN <= 32)
36 ; /* Original value is okay */
37 else if (ARCH_KMALLOC_MINALIGN <= 64)
39 else if (ARCH_KMALLOC_MINALIGN <= 128)
40 pool_max[0] = 0; /* Don't use this pool */
42 BUILD_BUG(); /* We don't allow this */
45 /* SETUP primitives */
48 * hcd_buffer_create - initialize buffer pools
49 * @hcd: the bus whose buffer pools are to be initialized
50 * Context: !in_interrupt()
52 * Call this as part of initializing a host controller that uses the dma
53 * memory allocators. It initializes some pools of dma-coherent memory that
54 * will be shared by all drivers using that controller.
56 * Call hcd_buffer_destroy() to clean up after using those pools.
58 * Return: 0 if successful. A negative errno value otherwise.
60 int hcd_buffer_create(struct usb_hcd *hcd)
65 if (!hcd->self.controller->dma_mask &&
66 !(hcd->driver->flags & HCD_LOCAL_MEM))
69 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
73 snprintf(name, sizeof(name), "buffer-%d", size);
74 hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
77 hcd_buffer_destroy(hcd);
86 * hcd_buffer_destroy - deallocate buffer pools
87 * @hcd: the bus whose buffer pools are to be destroyed
88 * Context: !in_interrupt()
90 * This frees the buffer pools created by hcd_buffer_create().
92 void hcd_buffer_destroy(struct usb_hcd *hcd)
96 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
97 struct dma_pool *pool = hcd->pool[i];
100 dma_pool_destroy(pool);
107 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
108 * better sharing and to leverage mm/slab.c intelligence.
111 void *hcd_buffer_alloc(
118 struct usb_hcd *hcd = bus_to_hcd(bus);
121 /* some USB hosts just use PIO */
122 if (!bus->controller->dma_mask &&
123 !(hcd->driver->flags & HCD_LOCAL_MEM)) {
124 *dma = ~(dma_addr_t) 0;
125 return kmalloc(size, mem_flags);
128 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
129 if (size <= pool_max[i])
130 return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
132 return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
135 void hcd_buffer_free(
142 struct usb_hcd *hcd = bus_to_hcd(bus);
148 if (!bus->controller->dma_mask &&
149 !(hcd->driver->flags & HCD_LOCAL_MEM)) {
154 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
155 if (size <= pool_max[i]) {
156 dma_pool_free(hcd->pool[i], addr, dma);
160 dma_free_coherent(hcd->self.controller, size, addr, dma);