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 (!IS_ENABLED(CONFIG_HAS_DMA) ||
66 (!hcd->self.controller->dma_mask &&
67 !(hcd->driver->flags & HCD_LOCAL_MEM)))
70 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
74 snprintf(name, sizeof(name), "buffer-%d", size);
75 hcd->pool[i] = dma_pool_create(name, hcd->self.controller,
78 hcd_buffer_destroy(hcd);
87 * hcd_buffer_destroy - deallocate buffer pools
88 * @hcd: the bus whose buffer pools are to be destroyed
89 * Context: !in_interrupt()
91 * This frees the buffer pools created by hcd_buffer_create().
93 void hcd_buffer_destroy(struct usb_hcd *hcd)
97 if (!IS_ENABLED(CONFIG_HAS_DMA))
100 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
101 struct dma_pool *pool = hcd->pool[i];
104 dma_pool_destroy(pool);
111 /* sometimes alloc/free could use kmalloc with GFP_DMA, for
112 * better sharing and to leverage mm/slab.c intelligence.
115 void *hcd_buffer_alloc(
122 struct usb_hcd *hcd = bus_to_hcd(bus);
125 /* some USB hosts just use PIO */
126 if (!IS_ENABLED(CONFIG_HAS_DMA) ||
127 (!bus->controller->dma_mask &&
128 !(hcd->driver->flags & HCD_LOCAL_MEM))) {
129 *dma = ~(dma_addr_t) 0;
130 return kmalloc(size, mem_flags);
133 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
134 if (size <= pool_max[i])
135 return dma_pool_alloc(hcd->pool[i], mem_flags, dma);
137 return dma_alloc_coherent(hcd->self.controller, size, dma, mem_flags);
140 void hcd_buffer_free(
147 struct usb_hcd *hcd = bus_to_hcd(bus);
153 if (!IS_ENABLED(CONFIG_HAS_DMA) ||
154 (!bus->controller->dma_mask &&
155 !(hcd->driver->flags & HCD_LOCAL_MEM))) {
160 for (i = 0; i < HCD_BUFFER_POOLS; i++) {
161 if (size <= pool_max[i]) {
162 dma_pool_free(hcd->pool[i], addr, dma);
166 dma_free_coherent(hcd->self.controller, size, addr, dma);