powerpc: Add support for swiotlb on 32-bit
This patch includes the basic infrastructure to use swiotlb
bounce buffering on 32-bit powerpc. It is not yet enabled on
any platforms. Probably the most interesting bit is the
addition of addr_needs_map to dma_ops - we need this as
a dma_op because the decision of whether or not an addr
can be mapped by a device is device-specific.
Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index cbc359f..65cf365 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -82,6 +82,7 @@
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
+obj-$(CONFIG_SWIOTLB) += dma-swiotlb.o
pci64-$(CONFIG_PPC64) += pci_dn.o isa-bridge.o
obj-$(CONFIG_PCI) += pci_$(CONFIG_WORD_SIZE).o $(pci64-y) \
diff --git a/arch/powerpc/kernel/dma-swiotlb.c b/arch/powerpc/kernel/dma-swiotlb.c
new file mode 100644
index 0000000..68ccf11
--- /dev/null
+++ b/arch/powerpc/kernel/dma-swiotlb.c
@@ -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;
+}
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index 6b02793..20a60d6 100644
--- a/arch/powerpc/kernel/dma.c
+++ b/arch/powerpc/kernel/dma.c
@@ -19,7 +19,7 @@
* default the offset is PCI_DRAM_OFFSET.
*/
-static unsigned long get_dma_direct_offset(struct device *dev)
+unsigned long get_dma_direct_offset(struct device *dev)
{
if (dev)
return (unsigned long)dev->archdata.dma_data;
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 9e1ca74..1d15424 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -39,6 +39,7 @@
#include <asm/serial.h>
#include <asm/udbg.h>
#include <asm/mmu_context.h>
+#include <asm/swiotlb.h>
#include "setup.h"
@@ -332,6 +333,11 @@
ppc_md.setup_arch();
if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
+#ifdef CONFIG_SWIOTLB
+ if (ppc_swiotlb_enable)
+ swiotlb_init();
+#endif
+
paging_init();
/* Initialize the MMU context management stuff */
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 4222105..f46548e 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -61,6 +61,7 @@
#include <asm/xmon.h>
#include <asm/udbg.h>
#include <asm/kexec.h>
+#include <asm/swiotlb.h>
#include "setup.h"
@@ -527,6 +528,11 @@
if (ppc_md.setup_arch)
ppc_md.setup_arch();
+#ifdef CONFIG_SWIOTLB
+ if (ppc_swiotlb_enable)
+ swiotlb_init();
+#endif
+
paging_init();
ppc64_boot_msg(0x15, "Setup Done");
}