Merge Qualcom Hexagon architecture

This is the fifth version of the patchset (with one tiny whitespace fix)
to the Linux kernel to support the Qualcomm Hexagon architecture.

Between now and the next pull requests, Richard Kuo should have his key
signed, etc., and should be back on kernel.org.  In the meantime, this
got merged as a emailed patch-series.

* Hexagon: (36 commits)
  Add extra arch overrides to asm-generic/checksum.h
  Hexagon: Add self to MAINTAINERS
  Hexagon: Add basic stacktrace functionality for Hexagon architecture.
  Hexagon: Add configuration and makefiles for the Hexagon architecture.
  Hexagon: Comet platform support
  Hexagon: kgdb support files
  Hexagon: Add page-fault support.
  Hexagon: Add page table header files & etc.
  Hexagon: Add ioremap support
  Hexagon: Provide DMA implementation
  Hexagon: Implement basic TLB management routines for Hexagon.
  Hexagon: Implement basic cache-flush support
  Hexagon: Provide basic implementation and/or stubs for I/O routines.
  Hexagon: Add user access functions
  Hexagon: Add locking types and functions
  Hexagon: Add SMP support
  Hexagon: Provide basic debugging and system trap support.
  Hexagon: Add ptrace support
  Hexagon: Add time and timer functions
  Hexagon: Add interrupts
  ...

1 files changed, 220 insertions, 0 deletions

diff --git a/arch/hexagon/kernel/dma.c b/arch/hexagon/kernel/dma.c
new file mode 100644
index 0000000..e711ace
--- /dev/null
+++ b/arch/hexagon/kernel/dma.c
@@ -0,0 +1,220 @@
+/*
+ * DMA implementation for Hexagon
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/bootmem.h>
+#include <linux/genalloc.h>
+#include <asm/dma-mapping.h>
+
+struct dma_map_ops *dma_ops;
+EXPORT_SYMBOL(dma_ops);
+
+int bad_dma_address;  /*  globals are automatically initialized to zero  */
+
+int dma_supported(struct device *dev, u64 mask)
+{
+	if (mask == DMA_BIT_MASK(32))
+		return 1;
+	else
+		return 0;
+}
+EXPORT_SYMBOL(dma_supported);
+
+int dma_set_mask(struct device *dev, u64 mask)
+{
+	if (!dev->dma_mask || !dma_supported(dev, mask))
+		return -EIO;
+
+	*dev->dma_mask = mask;
+
+	return 0;
+}
+EXPORT_SYMBOL(dma_set_mask);
+
+static struct gen_pool *coherent_pool;
+
+
+/* Allocates from a pool of uncached memory that was reserved at boot time */
+
+void *hexagon_dma_alloc_coherent(struct device *dev, size_t size,
+				 dma_addr_t *dma_addr, gfp_t flag)
+{
+	void *ret;
+
+	if (coherent_pool == NULL) {
+		coherent_pool = gen_pool_create(PAGE_SHIFT, -1);
+
+		if (coherent_pool == NULL)
+			panic("Can't create %s() memory pool!", __func__);
+		else
+			gen_pool_add(coherent_pool,
+				(PAGE_OFFSET + (max_low_pfn << PAGE_SHIFT)),
+				hexagon_coherent_pool_size, -1);
+	}
+
+	ret = (void *) gen_pool_alloc(coherent_pool, size);
+
+	if (ret) {
+		memset(ret, 0, size);
+		*dma_addr = (dma_addr_t) (ret - PAGE_OFFSET);
+	} else
+		*dma_addr = ~0;
+
+	return ret;
+}
+
+static void hexagon_free_coherent(struct device *dev, size_t size, void *vaddr,
+				  dma_addr_t dma_addr)
+{
+	gen_pool_free(coherent_pool, (unsigned long) vaddr, size);
+}
+
+static int check_addr(const char *name, struct device *hwdev,
+		      dma_addr_t bus, size_t size)
+{
+	if (hwdev && hwdev->dma_mask && !dma_capable(hwdev, bus, size)) {
+		if (*hwdev->dma_mask >= DMA_BIT_MASK(32))
+			printk(KERN_ERR
+				"%s: overflow %Lx+%zu of device mask %Lx\n",
+				name, (long long)bus, size,
+				(long long)*hwdev->dma_mask);
+		return 0;
+	}
+	return 1;
+}
+
+static int hexagon_map_sg(struct device *hwdev, struct scatterlist *sg,
+			  int nents, enum dma_data_direction dir,
+			  struct dma_attrs *attrs)
+{
+	struct scatterlist *s;
+	int i;
+
+	WARN_ON(nents == 0 || sg[0].length == 0);
+
+	for_each_sg(sg, s, nents, i) {
+		s->dma_address = sg_phys(s);
+		if (!check_addr("map_sg", hwdev, s->dma_address, s->length))
+			return 0;
+
+		s->dma_length = s->length;
+
+		flush_dcache_range(PAGE_OFFSET + s->dma_address,
+				   PAGE_OFFSET + s->dma_address + s->length);
+	}
+
+	return nents;
+}
+
+/*
+ * address is virtual
+ */
+static inline void dma_sync(void *addr, size_t size,
+			    enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_TO_DEVICE:
+		hexagon_clean_dcache_range((unsigned long) addr,
+		(unsigned long) addr + size);
+		break;
+	case DMA_FROM_DEVICE:
+		hexagon_inv_dcache_range((unsigned long) addr,
+		(unsigned long) addr + size);
+		break;
+	case DMA_BIDIRECTIONAL:
+		flush_dcache_range((unsigned long) addr,
+		(unsigned long) addr + size);
+		break;
+	default:
+		BUG();
+	}
+}
+
+static inline void *dma_addr_to_virt(dma_addr_t dma_addr)
+{
+	return phys_to_virt((unsigned long) dma_addr);
+}
+
+/**
+ * hexagon_map_page() - maps an address for device DMA
+ * @dev:	pointer to DMA device
+ * @page:	pointer to page struct of DMA memory
+ * @offset:	offset within page
+ * @size:	size of memory to map
+ * @dir:	transfer direction
+ * @attrs:	pointer to DMA attrs (not used)
+ *
+ * Called to map a memory address to a DMA address prior
+ * to accesses to/from device.
+ *
+ * We don't particularly have many hoops to jump through
+ * so far.  Straight translation between phys and virtual.
+ *
+ * DMA is not cache coherent so sync is necessary; this
+ * seems to be a convenient place to do it.
+ *
+ */
+static dma_addr_t hexagon_map_page(struct device *dev, struct page *page,
+				   unsigned long offset, size_t size,
+				   enum dma_data_direction dir,
+				   struct dma_attrs *attrs)
+{
+	dma_addr_t bus = page_to_phys(page) + offset;
+	WARN_ON(size == 0);
+
+	if (!check_addr("map_single", dev, bus, size))
+		return bad_dma_address;
+
+	dma_sync(dma_addr_to_virt(bus), size, dir);
+
+	return bus;
+}
+
+static void hexagon_sync_single_for_cpu(struct device *dev,
+					dma_addr_t dma_handle, size_t size,
+					enum dma_data_direction dir)
+{
+	dma_sync(dma_addr_to_virt(dma_handle), size, dir);
+}
+
+static void hexagon_sync_single_for_device(struct device *dev,
+					dma_addr_t dma_handle, size_t size,
+					enum dma_data_direction dir)
+{
+	dma_sync(dma_addr_to_virt(dma_handle), size, dir);
+}
+
+struct dma_map_ops hexagon_dma_ops = {
+	.alloc_coherent	= hexagon_dma_alloc_coherent,
+	.free_coherent	= hexagon_free_coherent,
+	.map_sg		= hexagon_map_sg,
+	.map_page	= hexagon_map_page,
+	.sync_single_for_cpu = hexagon_sync_single_for_cpu,
+	.sync_single_for_device = hexagon_sync_single_for_device,
+	.is_phys	= 1,
+};
+
+void __init hexagon_dma_init(void)
+{
+	if (dma_ops)
+		return;
+
+	dma_ops = &hexagon_dma_ops;
+}