Re: [PATCH 4/7] swiotlb: Allow arch override of address_needs_mapping
From: Kumar Gala
Date: Thu Apr 09 2009 - 16:26:56 EST
Here's the WIP patch for the PPC changes to give some sense of what we
need out of swiotlb for PPC.
- k
---
arch/powerpc/include/asm/dma-mapping.h | 18 ++++
arch/powerpc/include/asm/scatterlist.h | 6 +-
arch/powerpc/include/asm/swiotlb.h | 15 +++
arch/powerpc/kernel/Makefile | 1 +
arch/powerpc/kernel/dma-swiotlb.c | 154 ++++++++++++++++++++++++++++
arch/powerpc/kernel/dma.c | 2 +-
arch/powerpc/kernel/pci-common.c | 2 +
arch/powerpc/kernel/setup_32.c | 4 +
10 files changed, 211 insertions(+), 7 deletions(-)
create mode 100644 arch/powerpc/include/asm/swiotlb.h
create mode 100644 arch/powerpc/kernel/dma-swiotlb.c
diff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h
index c69f2b5..db6edfe 100644
--- a/arch/powerpc/include/asm/dma-mapping.h
+++ b/arch/powerpc/include/asm/dma-mapping.h
@@ -16,8 +16,18 @@
#include <linux/dma-attrs.h>
#include <asm/io.h>
+#ifdef CONFIG_SWIOTLB
+#include <asm/swiotlb.h>
+#endif
+
#define DMA_ERROR_CODE (~(dma_addr_t)0x0)
+/* Some dma direct funcs must be visible for use in other dma_ops */
+extern void *dma_direct_alloc_coherent(struct device *dev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag);
+extern void dma_direct_free_coherent(struct device *dev, size_t size,
+ void *vaddr, dma_addr_t dma_handle);
+
#ifdef CONFIG_NOT_COHERENT_CACHE
/*
* DMA-consistent mapping functions for PowerPCs that don't support
@@ -112,11 +122,19 @@ static inline struct dma_mapping_ops *get_dma_ops(struct device *dev)
if (unlikely(dev == NULL))
return NULL;
+ /* BGILL - temp code to look for problems */
+ if(dev->archdata.dma_ops == NULL)
+ printk(KERN_EMERG "dev %s has null dma_ops\n", dev->bus->name);
+
return dev->archdata.dma_ops;
}
static inline void set_dma_ops(struct device *dev, struct dma_mapping_ops *ops)
{
+ printk(KERN_EMERG "Setting dma_ops to %s\n",
+ (ops == &dma_direct_ops) ? "dma_direct_ops" :
+ ((ops == &swiotlb_dma_ops) ? "swiotlb_dma_ops" : "unknown"));
+
dev->archdata.dma_ops = ops;
}
diff --git a/arch/powerpc/include/asm/scatterlist.h b/arch/powerpc/include/asm/scatterlist.h
index fcf7d55..912bf59 100644
--- a/arch/powerpc/include/asm/scatterlist.h
+++ b/arch/powerpc/include/asm/scatterlist.h
@@ -21,7 +21,7 @@ struct scatterlist {
unsigned int offset;
unsigned int length;
- /* For TCE support */
+ /* For TCE or SWIOTLB support */
dma_addr_t dma_address;
u32 dma_length;
};
@@ -34,11 +34,7 @@ struct scatterlist {
* is 0.
*/
#define sg_dma_address(sg) ((sg)->dma_address)
-#ifdef __powerpc64__
#define sg_dma_len(sg) ((sg)->dma_length)
-#else
-#define sg_dma_len(sg) ((sg)->length)
-#endif
#ifdef __powerpc64__
#define ISA_DMA_THRESHOLD (~0UL)
diff --git a/arch/powerpc/include/asm/swiotlb.h b/arch/powerpc/include/asm/swiotlb.h
new file mode 100644
index 0000000..cbfce6c
--- /dev/null
+++ b/arch/powerpc/include/asm/swiotlb.h
@@ -0,0 +1,15 @@
+#ifndef __ASM_SWIOTLB_H
+#define __ASM_SWIOTLB_H
+
+#include <linux/swiotlb.h>
+
+extern int swiotlb_force;
+extern int swiotlb;
+extern struct dma_mapping_ops swiotlb_dma_ops;
+
+int swiotlb_arch_address_needs_mapping(struct device *, dma_addr_t,
+ size_t size);
+
+static inline void dma_mark_clean(void *addr, size_t size) {}
+
+#endif /* __ASM_SWIOTLB_H */
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 71901fb..34c0a95 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -82,6 +82,7 @@ obj-$(CONFIG_SMP) += smp.o
obj-$(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..639f3bc
--- /dev/null
+++ b/arch/powerpc/kernel/dma-swiotlb.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2009 Becky Bruce, Freescale Semiconductor
+ *
+ * swiotlb dma ops and functions required by the swiotlb code.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/pfn.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include <asm/machdep.h>
+#include <asm/swiotlb.h>
+#include <asm/dma.h>
+#include <asm/abs_addr.h>
+
+int swiotlb __read_mostly;
+
+unsigned long get_dma_direct_offset(struct device *dev);
+
+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;
+}
+
+#if 0 /* BGILL - don't need */
+/* This can only be called on pages with a kernel mapping */
+dma_addr_t swiotlb_virt_to_bus(struct device *hwdev, void *addr)
+{
+ return swiotlb_phys_to_bus(hwdev, virt_to_abs((unsigned long)addr));
+}
+#endif
+
+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));
+}
+
+/*
+ * Eventually, we should really be looking at some per-device
+ * quantity stored in archdata, and not a global value, since this is
+ * only needed for devices like PCI that use part of their 32 bit address
+ * space for something other than mapping memory.
+ *
+ * For now, require swiotlb mapping above MAX_32B_DIRECT_DMA_ADDR for devs
+ * that are not 64-bit capable. This should be determined using the PCI mem
+ * allocations in the devtree. -beckyb
+ */
+#define MAX_32B_DIRECT_DMA_ADDR 0x80000000
+
+/* determine if an address needs bounce buffering via swiotlb. */
+int
+swiotlb_arch_address_needs_mapping(struct device *hwdev, dma_addr_t addr,
+ size_t size)
+{
+ dma_addr_t mask = DMA_BIT_MASK(32);
+
+ /* Max dma_address we can access without bounce buffering */
+ dma_addr_t max = swiotlb_phys_to_bus(hwdev, MAX_32B_DIRECT_DMA_ADDR);
+
+ /* BGILL - can we get rid of this? */
+ if (hwdev && hwdev->dma_mask)
+ mask = *hwdev->dma_mask;
+
+ if ((mask <= DMA_BIT_MASK(36)) && (addr + size > max))
+ return 1;
+
+ return !is_buffer_dma_capable(mask, 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 = {
+#if 0
+ .alloc_coherent = dma_direct_alloc_coherent,
+ .free_coherent = dma_direct_free_coherent,
+#else
+ .alloc_coherent = swiotlb_alloc_coherent,
+ .free_coherent = swiotlb_free_coherent,
+#endif
+ .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,
+ .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;
+
+#if 0 /* BGILL - should look like this; use other form for debug */
+ if(dma_get_mask(dev) < DMA_BIT_MASK(36))
+ set_dma_ops(dev, &swiotlb_dma_ops);
+#else
+ if(!dev->dma_mask) {
+ printk(KERN_EMERG "ERROR: no dma_mask set for dev\n");
+ set_dma_ops(dev, &swiotlb_dma_ops);
+ }
+ else if(*dev->dma_mask < DMA_BIT_MASK(36)) {
+ set_dma_ops(dev, &swiotlb_dma_ops);
+ }
+ else
+ printk(KERN_EMERG "ERROR; fall thru with direct_ops\n");
+#endif
+
+ 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,
+};
+
+static int __init 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;
+}
+
+machine_arch_initcall(mpc86xx_hpcn, setup_bus_notifier);
+
diff --git a/arch/powerpc/kernel/dma.c b/arch/powerpc/kernel/dma.c
index 53c7788..62d80c4 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..f038b13 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -332,6 +332,10 @@ void __init setup_arch(char **cmdline_p)
ppc_md.setup_arch();
if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
+ /* Allow iotlb to do it's setup */
+#ifdef CONFIG_SWIOTLB
+ swiotlb_init();
+#endif
paging_init();
/* Initialize the MMU context management stuff */
--
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