118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 2014 Kevin Cernekee <cernekee@gmail.com>
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*/
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#define pr_fmt(fmt) "bmips-dma: " fmt
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#include <linux/device.h>
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#include <linux/dma-direction.h>
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#include <linux/dma-mapping.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/printk.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <dma-coherence.h>
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/*
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* BCM338x has configurable address translation windows which allow the
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* peripherals' DMA addresses to be different from the Zephyr-visible
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* physical addresses. e.g. usb_dma_addr = zephyr_pa ^ 0x08000000
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*
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* If the "brcm,ubus" node has a "dma-ranges" property we will enable this
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* translation globally using the provided information. This implements a
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* very limited subset of "dma-ranges" support and it will probably be
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* replaced by a more generic version later.
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*/
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struct bmips_dma_range {
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u32 child_addr;
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u32 parent_addr;
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u32 size;
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};
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static struct bmips_dma_range *bmips_dma_ranges;
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#define FLUSH_RAC 0x100
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static dma_addr_t bmips_phys_to_dma(struct device *dev, phys_addr_t pa)
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{
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struct bmips_dma_range *r;
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for (r = bmips_dma_ranges; r && r->size; r++) {
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if (pa >= r->child_addr &&
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pa < (r->child_addr + r->size))
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return pa - r->child_addr + r->parent_addr;
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}
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return pa;
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}
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dma_addr_t plat_map_dma_mem(struct device *dev, void *addr, size_t size)
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{
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return bmips_phys_to_dma(dev, virt_to_phys(addr));
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}
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dma_addr_t plat_map_dma_mem_page(struct device *dev, struct page *page)
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{
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return bmips_phys_to_dma(dev, page_to_phys(page));
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}
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unsigned long plat_dma_addr_to_phys(struct device *dev, dma_addr_t dma_addr)
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{
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struct bmips_dma_range *r;
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for (r = bmips_dma_ranges; r && r->size; r++) {
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if (dma_addr >= r->parent_addr &&
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dma_addr < (r->parent_addr + r->size))
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return dma_addr - r->parent_addr + r->child_addr;
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}
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return dma_addr;
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}
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static int __init bmips_init_dma_ranges(void)
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{
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struct device_node *np =
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of_find_compatible_node(NULL, NULL, "brcm,ubus");
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const __be32 *data;
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struct bmips_dma_range *r;
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int len;
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if (!np)
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return 0;
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data = of_get_property(np, "dma-ranges", &len);
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if (!data)
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goto out_good;
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len /= sizeof(*data) * 3;
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if (!len)
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goto out_bad;
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/* add a dummy (zero) entry at the end as a sentinel */
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bmips_dma_ranges = kcalloc(len + 1, sizeof(struct bmips_dma_range),
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GFP_KERNEL);
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if (!bmips_dma_ranges)
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goto out_bad;
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for (r = bmips_dma_ranges; len; len--, r++) {
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r->child_addr = be32_to_cpup(data++);
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r->parent_addr = be32_to_cpup(data++);
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r->size = be32_to_cpup(data++);
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}
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out_good:
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of_node_put(np);
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return 0;
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out_bad:
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pr_err("error parsing dma-ranges property\n");
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of_node_put(np);
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return -EINVAL;
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}
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arch_initcall(bmips_init_dma_ranges);
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