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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 | // SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2018 Arm Ltd * Author: Liviu Dudau <liviu.dudau@foss.arm.com> * */ #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 = dev_get_priv(dev); 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; if (!priv) return -ENOMEM; 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, .priv_auto = sizeof(struct vexpress_config_sysreg), }; |