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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | // SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2018 Arm Ltd * Author: Liviu Dudau <liviu.dudau@foss.arm.com> * */ #include <common.h> #include <dm.h> #include <malloc.h> #include <dm/read.h> #include <asm/io.h> #include <linux/bitops.h> #include <linux/delay.h> #include <misc.h> #define SYS_CFGDATA 0xa0 #define SYS_CFGCTRL 0xa4 #define SYS_CFGCTRL_START BIT(31) #define SYS_CFGCTRL_WRITE BIT(30) #define SYS_CFGSTAT 0xa8 #define SYS_CFGSTAT_ERR BIT(1) #define SYS_CFGSTAT_COMPLETE BIT(0) struct vexpress_config_sysreg { phys_addr_t addr; u32 site; }; static int vexpress_config_exec(struct vexpress_config_sysreg *syscfg, bool write, void *buf, int size) { u32 cmd, status, tries = 100; cmd = (*(u32 *)buf) | SYS_CFGCTRL_START | (syscfg->site << 16); if (!write) { /* write a canary in the data register for reads */ writel(0xdeadbeef, syscfg->addr + SYS_CFGDATA); } else { cmd |= SYS_CFGCTRL_WRITE; writel(((u32 *)buf)[1], syscfg->addr + SYS_CFGDATA); } writel(0, syscfg->addr + SYS_CFGSTAT); writel(cmd, syscfg->addr + SYS_CFGCTRL); /* completion of command takes ages, go to sleep (150us) */ do { udelay(150); status = readl(syscfg->addr + SYS_CFGSTAT); if (status & SYS_CFGSTAT_ERR) return -EFAULT; } while (--tries && !(status & SYS_CFGSTAT_COMPLETE)); if (!tries) return -ETIMEDOUT; if (!write) (*(u32 *)buf) = readl(syscfg->addr + SYS_CFGDATA); return 0; } static int vexpress_config_read(struct udevice *dev, int offset, void *buf, int size) { struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev); if (size != sizeof(u32)) return -EINVAL; return vexpress_config_exec(priv, false, buf, size); } static int vexpress_config_write(struct udevice *dev, int offset, const void *buf, int size) { struct vexpress_config_sysreg *priv = dev_get_uclass_priv(dev); if (size != sizeof(u32) * 2) return -EINVAL; return vexpress_config_exec(priv, true, (void *)buf, size); } static struct misc_ops vexpress_config_ops = { .read = vexpress_config_read, .write = vexpress_config_write, }; static int vexpress_config_probe(struct udevice *dev) { struct ofnode_phandle_args args; struct vexpress_config_sysreg *priv; const char *prop; int err, prop_size; err = dev_read_phandle_with_args(dev, "arm,vexpress,config-bridge", NULL, 0, 0, &args); if (err) return err; prop = ofnode_get_property(args.node, "compatible", &prop_size); if (!prop || (strncmp(prop, "arm,vexpress-sysreg", 19) != 0)) return -ENOENT; priv = calloc(1, sizeof(*priv)); if (!priv) return -ENOMEM; dev->uclass_priv = priv; priv->addr = ofnode_get_addr(args.node); return dev_read_u32(dev, "arm,vexpress,site", &priv->site); } static const struct udevice_id vexpress_config_ids[] = { { .compatible = "arm,vexpress,config-bus" }, { } }; U_BOOT_DRIVER(vexpress_config_drv) = { .name = "vexpress_config_bus", .id = UCLASS_MISC, .of_match = vexpress_config_ids, .bind = dm_scan_fdt_dev, .probe = vexpress_config_probe, .ops = &vexpress_config_ops, }; |