xref: /openbmc/linux/arch/powerpc/kernel/dma-swiotlb.c (revision cf562103)

/*
 * Contains routines needed to support swiotlb for ppc.
 *
 * Copyright (C) 2009-2010 Freescale Semiconductor, Inc.
 * Author: Becky Bruce
 *
 * 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/memblock.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>

unsigned int ppc_swiotlb_enable;

static u64 swiotlb_powerpc_get_required(struct device *dev)
{
	u64 end, mask, max_direct_dma_addr = dev->archdata.max_direct_dma_addr;

	end = memblock_end_of_DRAM();
	if (max_direct_dma_addr && end > max_direct_dma_addr)
		end = max_direct_dma_addr;
	end += get_dma_offset(dev);

	mask = 1ULL << (fls64(end) - 1);
	mask += mask - 1;

	return mask;
}

/*
 * 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_map_ops swiotlb_dma_ops = {
	.alloc = dma_direct_alloc_coherent,
	.free = dma_direct_free_coherent,
	.mmap = dma_direct_mmap_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,
	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
	.sync_single_for_device = swiotlb_sync_single_for_device,
	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
	.sync_sg_for_device = swiotlb_sync_sg_for_device,
	.mapping_error = swiotlb_dma_mapping_error,
	.get_required_mask = swiotlb_powerpc_get_required,
};

void pci_dma_dev_setup_swiotlb(struct pci_dev *pdev)
{
	struct pci_controller *hose;
	struct dev_archdata *sd;

	hose = pci_bus_to_host(pdev->bus);
	sd = &pdev->dev.archdata;
	sd->max_direct_dma_addr =
		hose->dma_window_base_cur + hose->dma_window_size;
}

static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
				  unsigned long action, void *data)
{
	struct device *dev = data;
	struct dev_archdata *sd;

	/* We are only intereted in device addition */
	if (action != BUS_NOTIFY_ADD_DEVICE)
		return 0;

	sd = &dev->archdata;
	sd->max_direct_dma_addr = 0;

	/* May need to bounce if the device can't address all of DRAM */
	if ((dma_get_mask(dev) + 1) < memblock_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,
};

int __init swiotlb_setup_bus_notifier(void)
{
	bus_register_notifier(&platform_bus_type,
			      &ppc_swiotlb_plat_bus_notifier);
	return 0;
}

void __init swiotlb_detect_4g(void)
{
	if ((memblock_end_of_DRAM() - 1) > 0xffffffff) {
		ppc_swiotlb_enable = 1;
#ifdef CONFIG_ZONE_DMA32
		limit_zone_pfn(ZONE_DMA32, (1ULL << 32) >> PAGE_SHIFT);
#endif
	}
}

static int __init swiotlb_late_init(void)
{
	if (ppc_swiotlb_enable) {
		swiotlb_print_info();
		set_pci_dma_ops(&swiotlb_dma_ops);
		ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_swiotlb;
	} else {
		swiotlb_free();
	}

	return 0;
}
subsys_initcall(swiotlb_late_init);