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path: root/drivers/usb/core/buffer.c
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Diffstat (limited to 'drivers/usb/core/buffer.c')
-rw-r--r--drivers/usb/core/buffer.c154
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
new file mode 100644
index 00000000000..b7827df21f4
--- /dev/null
+++ b/drivers/usb/core/buffer.c
@@ -0,0 +1,154 @@
+/*
+ * DMA memory management for framework level HCD code (hc_driver)
+ *
+ * This implementation plugs in through generic "usb_bus" level methods,
+ * and should work with all USB controllers, regardles of bus type.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <asm/io.h>
+#include <asm/scatterlist.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+
+
+#ifdef CONFIG_USB_DEBUG
+ #define DEBUG
+#else
+ #undef DEBUG
+#endif
+
+#include <linux/usb.h>
+#include "hcd.h"
+
+
+/*
+ * DMA-Coherent Buffers
+ */
+
+/* FIXME tune these based on pool statistics ... */
+static const size_t pool_max [HCD_BUFFER_POOLS] = {
+ /* platforms without dma-friendly caches might need to
+ * prevent cacheline sharing...
+ */
+ 32,
+ 128,
+ 512,
+ PAGE_SIZE / 2
+ /* bigger --> allocate pages */
+};
+
+
+/* SETUP primitives */
+
+/**
+ * hcd_buffer_create - initialize buffer pools
+ * @hcd: the bus whose buffer pools are to be initialized
+ * Context: !in_interrupt()
+ *
+ * Call this as part of initializing a host controller that uses the dma
+ * memory allocators. It initializes some pools of dma-coherent memory that
+ * will be shared by all drivers using that controller, or returns a negative
+ * errno value on error.
+ *
+ * Call hcd_buffer_destroy() to clean up after using those pools.
+ */
+int hcd_buffer_create (struct usb_hcd *hcd)
+{
+ char name [16];
+ int i, size;
+
+ for (i = 0; i < HCD_BUFFER_POOLS; i++) {
+ if (!(size = pool_max [i]))
+ continue;
+ snprintf (name, sizeof name, "buffer-%d", size);
+ hcd->pool [i] = dma_pool_create (name, hcd->self.controller,
+ size, size, 0);
+ if (!hcd->pool [i]) {
+ hcd_buffer_destroy (hcd);
+ return -ENOMEM;
+ }
+ }
+ return 0;
+}
+
+
+/**
+ * hcd_buffer_destroy - deallocate buffer pools
+ * @hcd: the bus whose buffer pools are to be destroyed
+ * Context: !in_interrupt()
+ *
+ * This frees the buffer pools created by hcd_buffer_create().
+ */
+void hcd_buffer_destroy (struct usb_hcd *hcd)
+{
+ int i;
+
+ for (i = 0; i < HCD_BUFFER_POOLS; i++) {
+ struct dma_pool *pool = hcd->pool [i];
+ if (pool) {
+ dma_pool_destroy (pool);
+ hcd->pool[i] = NULL;
+ }
+ }
+}
+
+
+/* sometimes alloc/free could use kmalloc with SLAB_DMA, for
+ * better sharing and to leverage mm/slab.c intelligence.
+ */
+
+void *hcd_buffer_alloc (
+ struct usb_bus *bus,
+ size_t size,
+ int mem_flags,
+ dma_addr_t *dma
+)
+{
+ struct usb_hcd *hcd = bus->hcpriv;
+ int i;
+
+ /* some USB hosts just use PIO */
+ if (!bus->controller->dma_mask) {
+ *dma = ~(dma_addr_t) 0;
+ return kmalloc (size, mem_flags);
+ }
+
+ for (i = 0; i < HCD_BUFFER_POOLS; i++) {
+ if (size <= pool_max [i])
+ return dma_pool_alloc (hcd->pool [i], mem_flags, dma);
+ }
+ return dma_alloc_coherent (hcd->self.controller, size, dma, 0);
+}
+
+void hcd_buffer_free (
+ struct usb_bus *bus,
+ size_t size,
+ void *addr,
+ dma_addr_t dma
+)
+{
+ struct usb_hcd *hcd = bus->hcpriv;
+ int i;
+
+ if (!addr)
+ return;
+
+ if (!bus->controller->dma_mask) {
+ kfree (addr);
+ return;
+ }
+
+ for (i = 0; i < HCD_BUFFER_POOLS; i++) {
+ if (size <= pool_max [i]) {
+ dma_pool_free (hcd->pool [i], addr, dma);
+ return;
+ }
+ }
+ dma_free_coherent (hcd->self.controller, size, addr, dma);
+}