1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/usb/core/buffer.c b/drivers/usb/core/buffer.c
new file mode 100644
index 00000000..b0585e62
--- /dev/null
+++ b/drivers/usb/core/buffer.c
@@ -0,0 +1,151 @@
+/*
+ * 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/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/usb.h>
+#include <linux/usb/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;
+
+	if (!hcd->self.controller->dma_mask &&
+	    !(hcd->driver->flags & HCD_LOCAL_MEM))
+		return 0;
+
+	for (i = 0; i < HCD_BUFFER_POOLS; i++) {
+		size = pool_max[i];
+		if (!size)
+			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 GFP_DMA, for
+ * better sharing and to leverage mm/slab.c intelligence.
+ */
+
+void *hcd_buffer_alloc(
+	struct usb_bus		*bus,
+	size_t			size,
+	gfp_t			mem_flags,
+	dma_addr_t		*dma
+)
+{
+	struct usb_hcd		*hcd = bus_to_hcd(bus);
+	int			i;
+
+	/* some USB hosts just use PIO */
+	if (!bus->controller->dma_mask &&
+	    !(hcd->driver->flags & HCD_LOCAL_MEM)) {
+		*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, mem_flags);
+}
+
+void hcd_buffer_free(
+	struct usb_bus		*bus,
+	size_t			size,
+	void			*addr,
+	dma_addr_t		dma
+)
+{
+	struct usb_hcd		*hcd = bus_to_hcd(bus);
+	int			i;
+
+	if (!addr)
+		return;
+
+	if (!bus->controller->dma_mask &&
+	    !(hcd->driver->flags & HCD_LOCAL_MEM)) {
+		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);
+}