![Becky Bruce](/assets/img/avatar_default.png)
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>
164 lines
4.6 KiB
C
164 lines
4.6 KiB
C
/*
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* Contains routines needed to support swiotlb for ppc.
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*
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* Copyright (C) 2009 Becky Bruce, Freescale Semiconductor
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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*/
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#include <linux/dma-mapping.h>
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#include <linux/pfn.h>
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#include <linux/of_platform.h>
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#include <linux/platform_device.h>
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#include <linux/pci.h>
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#include <asm/machdep.h>
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#include <asm/swiotlb.h>
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#include <asm/dma.h>
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#include <asm/abs_addr.h>
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int swiotlb __read_mostly;
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unsigned int ppc_swiotlb_enable;
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void *swiotlb_bus_to_virt(struct device *hwdev, dma_addr_t addr)
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{
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unsigned long pfn = PFN_DOWN(swiotlb_bus_to_phys(hwdev, addr));
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void *pageaddr = page_address(pfn_to_page(pfn));
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if (pageaddr != NULL)
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return pageaddr + (addr % PAGE_SIZE);
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return NULL;
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}
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dma_addr_t swiotlb_phys_to_bus(struct device *hwdev, phys_addr_t paddr)
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{
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return paddr + get_dma_direct_offset(hwdev);
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}
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phys_addr_t swiotlb_bus_to_phys(struct device *hwdev, dma_addr_t baddr)
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{
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return baddr - get_dma_direct_offset(hwdev);
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}
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/*
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* Determine if an address needs bounce buffering via swiotlb.
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* Going forward I expect the swiotlb code to generalize on using
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* a dma_ops->addr_needs_map, and this function will move from here to the
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* generic swiotlb code.
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*/
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int
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swiotlb_arch_address_needs_mapping(struct device *hwdev, dma_addr_t addr,
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size_t size)
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{
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struct dma_mapping_ops *dma_ops = get_dma_ops(hwdev);
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BUG_ON(!dma_ops);
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return dma_ops->addr_needs_map(hwdev, addr, size);
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}
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/*
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* Determine if an address is reachable by a pci device, or if we must bounce.
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*/
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static int
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swiotlb_pci_addr_needs_map(struct device *hwdev, dma_addr_t addr, size_t size)
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{
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u64 mask = dma_get_mask(hwdev);
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dma_addr_t max;
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struct pci_controller *hose;
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struct pci_dev *pdev = to_pci_dev(hwdev);
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hose = pci_bus_to_host(pdev->bus);
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max = hose->dma_window_base_cur + hose->dma_window_size;
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/* check that we're within mapped pci window space */
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if ((addr + size > max) | (addr < hose->dma_window_base_cur))
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return 1;
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return !is_buffer_dma_capable(mask, addr, size);
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}
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static int
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swiotlb_addr_needs_map(struct device *hwdev, dma_addr_t addr, size_t size)
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{
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return !is_buffer_dma_capable(dma_get_mask(hwdev), addr, size);
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}
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/*
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* At the moment, all platforms that use this code only require
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* swiotlb to be used if we're operating on HIGHMEM. Since
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* we don't ever call anything other than map_sg, unmap_sg,
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* map_page, and unmap_page on highmem, use normal dma_ops
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* for everything else.
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*/
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struct dma_mapping_ops swiotlb_dma_ops = {
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.alloc_coherent = dma_direct_alloc_coherent,
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.free_coherent = dma_direct_free_coherent,
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.map_sg = swiotlb_map_sg_attrs,
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.unmap_sg = swiotlb_unmap_sg_attrs,
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.dma_supported = swiotlb_dma_supported,
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.map_page = swiotlb_map_page,
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.unmap_page = swiotlb_unmap_page,
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.addr_needs_map = swiotlb_addr_needs_map,
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.sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
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.sync_single_range_for_device = swiotlb_sync_single_range_for_device,
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.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
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.sync_sg_for_device = swiotlb_sync_sg_for_device
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};
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struct dma_mapping_ops swiotlb_pci_dma_ops = {
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.alloc_coherent = dma_direct_alloc_coherent,
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.free_coherent = dma_direct_free_coherent,
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.map_sg = swiotlb_map_sg_attrs,
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.unmap_sg = swiotlb_unmap_sg_attrs,
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.dma_supported = swiotlb_dma_supported,
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.map_page = swiotlb_map_page,
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.unmap_page = swiotlb_unmap_page,
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.addr_needs_map = swiotlb_pci_addr_needs_map,
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.sync_single_range_for_cpu = swiotlb_sync_single_range_for_cpu,
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.sync_single_range_for_device = swiotlb_sync_single_range_for_device,
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.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
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.sync_sg_for_device = swiotlb_sync_sg_for_device
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};
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static int ppc_swiotlb_bus_notify(struct notifier_block *nb,
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unsigned long action, void *data)
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{
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struct device *dev = data;
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/* We are only intereted in device addition */
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if (action != BUS_NOTIFY_ADD_DEVICE)
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return 0;
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/* May need to bounce if the device can't address all of DRAM */
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if (dma_get_mask(dev) < lmb_end_of_DRAM())
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set_dma_ops(dev, &swiotlb_dma_ops);
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return NOTIFY_DONE;
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}
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static struct notifier_block ppc_swiotlb_plat_bus_notifier = {
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.notifier_call = ppc_swiotlb_bus_notify,
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.priority = 0,
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};
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static struct notifier_block ppc_swiotlb_of_bus_notifier = {
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.notifier_call = ppc_swiotlb_bus_notify,
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.priority = 0,
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};
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int __init swiotlb_setup_bus_notifier(void)
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{
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bus_register_notifier(&platform_bus_type,
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&ppc_swiotlb_plat_bus_notifier);
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bus_register_notifier(&of_platform_bus_type,
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&ppc_swiotlb_of_bus_notifier);
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return 0;
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}
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