powerpc: Add support for swiotlb on 32-bit
[pandora-kernel.git] / arch / powerpc / kernel / dma-swiotlb.c
diff --git a/arch/powerpc/kernel/dma-swiotlb.c b/arch/powerpc/kernel/dma-swiotlb.c
new file mode 100644 (file)
index 0000000..68ccf11
--- /dev/null
@@ -0,0 +1,163 @@
+/*
+ * Contains routines needed to support swiotlb for ppc.
+ *
+ * Copyright (C) 2009 Becky Bruce, Freescale Semiconductor
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/pfn.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/pci.h>
+
+#include <asm/machdep.h>
+#include <asm/swiotlb.h>
+#include <asm/dma.h>
+#include <asm/abs_addr.h>
+
+int swiotlb __read_mostly;
+unsigned int ppc_swiotlb_enable;
+
+void *swiotlb_bus_to_virt(struct device *hwdev, dma_addr_t addr)
+{
+       unsigned long pfn = PFN_DOWN(swiotlb_bus_to_phys(hwdev, addr));
+       void *pageaddr = page_address(pfn_to_page(pfn));
+
+       if (pageaddr != NULL)
+               return pageaddr + (addr % PAGE_SIZE);
+       return NULL;
+}
+
+dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
+{
+       return paddr + get_dma_direct_offset(hwdev);
+}
+
+phys_addr_t swiotlb_bus_to_phys(struct device *hwdev, dma_addr_t baddr)
+
+{
+       return baddr - get_dma_direct_offset(hwdev);
+}
+
+/*
+ * Determine if an address needs bounce buffering via swiotlb.
+ * Going forward I expect the swiotlb code to generalize on using
+ * a dma_ops->addr_needs_map, and this function will move from here to the
+ * generic swiotlb code.
+ */
+int
+swiotlb_arch_address_needs_mapping(struct device *hwdev, dma_addr_t addr,
+                                  size_t size)
+{
+       struct dma_mapping_ops *dma_ops = get_dma_ops(hwdev);
+
+       BUG_ON(!dma_ops);
+       return dma_ops->addr_needs_map(hwdev, addr, size);
+}
+
+/*
+ * Determine if an address is reachable by a pci device, or if we must bounce.
+ */
+static int
+swiotlb_pci_addr_needs_map(struct device *hwdev, dma_addr_t addr, size_t size)
+{
+       u64 mask = dma_get_mask(hwdev);
+       dma_addr_t max;
+       struct pci_controller *hose;
+       struct pci_dev *pdev = to_pci_dev(hwdev);
+
+       hose = pci_bus_to_host(pdev->bus);
+       max = hose->dma_window_base_cur + hose->dma_window_size;
+
+       /* check that we're within mapped pci window space */
+       if ((addr + size > max) | (addr < hose->dma_window_base_cur))
+               return 1;
+
+       return !is_buffer_dma_capable(mask, addr, size);
+}
+
+static int
+swiotlb_addr_needs_map(struct device *hwdev, dma_addr_t addr, size_t size)
+{
+       return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
+}
+
+
+/*
+ * At the moment, all platforms that use this code only require
+ * swiotlb to be used if we're operating on HIGHMEM.  Since
+ * we don't ever call anything other than map_sg, unmap_sg,
+ * map_page, and unmap_page on highmem, use normal dma_ops
+ * for everything else.
+ */
+struct dma_mapping_ops swiotlb_dma_ops = {
+       .alloc_coherent = dma_direct_alloc_coherent,
+       .free_coherent = dma_direct_free_coherent,
+       .map_sg = swiotlb_map_sg_attrs,
+       .unmap_sg = swiotlb_unmap_sg_attrs,
+       .dma_supported = swiotlb_dma_supported,
+       .map_page = swiotlb_map_page,
+       .unmap_page = swiotlb_unmap_page,
+       .addr_needs_map = swiotlb_addr_needs_map,
+       .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
+       .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
+       .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
+       .sync_sg_for_device = swiotlb_sync_sg_for_device
+};
+
+struct dma_mapping_ops swiotlb_pci_dma_ops = {
+       .alloc_coherent = dma_direct_alloc_coherent,
+       .free_coherent = dma_direct_free_coherent,
+       .map_sg = swiotlb_map_sg_attrs,
+       .unmap_sg = swiotlb_unmap_sg_attrs,
+       .dma_supported = swiotlb_dma_supported,
+       .map_page = swiotlb_map_page,
+       .unmap_page = swiotlb_unmap_page,
+       .addr_needs_map = swiotlb_pci_addr_needs_map,
+       .sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
+       .sync_single_range_for_device = swiotlb_sync_single_range_for_device,
+       .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
+       .sync_sg_for_device = swiotlb_sync_sg_for_device
+};
+
+static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
+                                 unsigned long action, void *data)
+{
+       struct device *dev = data;
+
+       /* We are only intereted in device addition */
+       if (action != BUS_NOTIFY_ADD_DEVICE)
+               return 0;
+
+       /* May need to bounce if the device can't address all of DRAM */
+       if (dma_get_mask(dev) < lmb_end_of_DRAM())
+               set_dma_ops(dev, &swiotlb_dma_ops);
+
+       return NOTIFY_DONE;
+}
+
+static struct notifier_block ppc_swiotlb_plat_bus_notifier = {
+       .notifier_call = ppc_swiotlb_bus_notify,
+       .priority = 0,
+};
+
+static struct notifier_block ppc_swiotlb_of_bus_notifier = {
+       .notifier_call = ppc_swiotlb_bus_notify,
+       .priority = 0,
+};
+
+int __init swiotlb_setup_bus_notifier(void)
+{
+       bus_register_notifier(&platform_bus_type,
+                             &ppc_swiotlb_plat_bus_notifier);
+       bus_register_notifier(&of_platform_bus_type,
+                             &ppc_swiotlb_of_bus_notifier);
+
+       return 0;
+}