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1// SPDX-License-Identifier: GPL-2.02/* Copyright (C) 2020 Maxime Ripard <maxime@cerno.tech> */3 4#include <linux/device.h>5#include <linux/dma-map-ops.h>6#include <linux/init.h>7#include <linux/notifier.h>8#include <linux/of.h>9#include <linux/platform_device.h>10 11static const char * const sunxi_mbus_devices[] = {12 /*13 * The display engine virtual devices are not strictly speaking14 * connected to the MBUS, but since DRM will perform all the15 * memory allocations and DMA operations through that device, we16 * need to have the quirk on those devices too.17 */18 "allwinner,sun4i-a10-display-engine",19 "allwinner,sun5i-a10s-display-engine",20 "allwinner,sun5i-a13-display-engine",21 "allwinner,sun6i-a31-display-engine",22 "allwinner,sun6i-a31s-display-engine",23 "allwinner,sun7i-a20-display-engine",24 "allwinner,sun8i-a23-display-engine",25 "allwinner,sun8i-a33-display-engine",26 "allwinner,sun9i-a80-display-engine",27 28 /*29 * And now we have the regular devices connected to the MBUS30 * (that we know of).31 */32 "allwinner,sun4i-a10-csi1",33 "allwinner,sun4i-a10-display-backend",34 "allwinner,sun4i-a10-display-frontend",35 "allwinner,sun4i-a10-video-engine",36 "allwinner,sun5i-a13-display-backend",37 "allwinner,sun5i-a13-video-engine",38 "allwinner,sun6i-a31-csi",39 "allwinner,sun6i-a31-display-backend",40 "allwinner,sun7i-a20-csi0",41 "allwinner,sun7i-a20-display-backend",42 "allwinner,sun7i-a20-display-frontend",43 "allwinner,sun7i-a20-video-engine",44 "allwinner,sun8i-a23-display-backend",45 "allwinner,sun8i-a23-display-frontend",46 "allwinner,sun8i-a33-display-backend",47 "allwinner,sun8i-a33-display-frontend",48 "allwinner,sun8i-a33-video-engine",49 "allwinner,sun8i-a83t-csi",50 "allwinner,sun8i-h3-csi",51 "allwinner,sun8i-h3-video-engine",52 "allwinner,sun8i-v3s-csi",53 "allwinner,sun9i-a80-display-backend",54 "allwinner,sun50i-a64-csi",55 "allwinner,sun50i-a64-video-engine",56 "allwinner,sun50i-h5-video-engine",57 NULL,58};59 60static int sunxi_mbus_notifier(struct notifier_block *nb,61 unsigned long event, void *__dev)62{63 struct device *dev = __dev;64 int ret;65 66 if (event != BUS_NOTIFY_ADD_DEVICE)67 return NOTIFY_DONE;68 69 /*70 * Only the devices that need a large memory bandwidth do DMA71 * directly over the memory bus (called MBUS), instead of going72 * through the regular system bus.73 */74 if (!of_device_compatible_match(dev->of_node, sunxi_mbus_devices))75 return NOTIFY_DONE;76 77 /*78 * Devices with an interconnects property have the MBUS79 * relationship described in their DT and dealt with by80 * of_dma_configure, so we can just skip them.81 *82 * Older DTs or SoCs who are not clearly understood need to set83 * that DMA offset though.84 */85 if (of_property_present(dev->of_node, "interconnects"))86 return NOTIFY_DONE;87 88 ret = dma_direct_set_offset(dev, PHYS_OFFSET, 0, SZ_4G);89 if (ret)90 dev_err(dev, "Couldn't setup our DMA offset: %d\n", ret);91 92 return NOTIFY_DONE;93}94 95static struct notifier_block sunxi_mbus_nb = {96 .notifier_call = sunxi_mbus_notifier,97};98 99static const char * const sunxi_mbus_platforms[] __initconst = {100 "allwinner,sun4i-a10",101 "allwinner,sun5i-a10s",102 "allwinner,sun5i-a13",103 "allwinner,sun6i-a31",104 "allwinner,sun7i-a20",105 "allwinner,sun8i-a23",106 "allwinner,sun8i-a33",107 "allwinner,sun8i-a83t",108 "allwinner,sun8i-h3",109 "allwinner,sun8i-r40",110 "allwinner,sun8i-v3",111 "allwinner,sun8i-v3s",112 "allwinner,sun9i-a80",113 "allwinner,sun50i-a64",114 "allwinner,sun50i-h5",115 "nextthing,gr8",116 NULL,117};118 119static int __init sunxi_mbus_init(void)120{121 if (!of_device_compatible_match(of_root, sunxi_mbus_platforms))122 return 0;123 124 bus_register_notifier(&platform_bus_type, &sunxi_mbus_nb);125 return 0;126}127arch_initcall(sunxi_mbus_init);128