1 /* 2 * (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org> 3 * 4 * Derived from pl01x code: 5 * 6 * (C) Copyright 2000 7 * Rob Taylor, Flying Pig Systems. robt@flyingpig.com. 8 * 9 * (C) Copyright 2004 10 * ARM Ltd. 11 * Philippe Robin, <philippe.robin@arm.com> 12 * 13 * SPDX-License-Identifier: GPL-2.0+ 14 */ 15 16 /* Simple U-Boot driver for the BCM283x mini UART */ 17 18 #include <common.h> 19 #include <dm.h> 20 #include <errno.h> 21 #include <watchdog.h> 22 #include <asm/io.h> 23 #include <serial.h> 24 #include <dm/platform_data/serial_bcm283x_mu.h> 25 #include <linux/compiler.h> 26 #include <fdtdec.h> 27 28 DECLARE_GLOBAL_DATA_PTR; 29 30 struct bcm283x_mu_regs { 31 u32 io; 32 u32 iir; 33 u32 ier; 34 u32 lcr; 35 u32 mcr; 36 u32 lsr; 37 u32 msr; 38 u32 scratch; 39 u32 cntl; 40 u32 stat; 41 u32 baud; 42 }; 43 44 #define BCM283X_MU_LCR_DATA_SIZE_8 3 45 46 #define BCM283X_MU_LSR_TX_IDLE BIT(6) 47 /* This actually means not full, but is named not empty in the docs */ 48 #define BCM283X_MU_LSR_TX_EMPTY BIT(5) 49 #define BCM283X_MU_LSR_RX_READY BIT(0) 50 51 struct bcm283x_mu_priv { 52 struct bcm283x_mu_regs *regs; 53 }; 54 55 static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate) 56 { 57 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); 58 struct bcm283x_mu_priv *priv = dev_get_priv(dev); 59 struct bcm283x_mu_regs *regs = priv->regs; 60 u32 divider; 61 62 if (plat->skip_init) 63 return 0; 64 65 divider = plat->clock / (baudrate * 8); 66 67 writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr); 68 writel(divider - 1, ®s->baud); 69 70 return 0; 71 } 72 73 static int bcm283x_mu_serial_probe(struct udevice *dev) 74 { 75 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); 76 struct bcm283x_mu_priv *priv = dev_get_priv(dev); 77 78 if (plat->disabled) 79 return -ENODEV; 80 81 priv->regs = (struct bcm283x_mu_regs *)plat->base; 82 83 return 0; 84 } 85 86 static int bcm283x_mu_serial_getc(struct udevice *dev) 87 { 88 struct bcm283x_mu_priv *priv = dev_get_priv(dev); 89 struct bcm283x_mu_regs *regs = priv->regs; 90 u32 data; 91 92 /* Wait until there is data in the FIFO */ 93 if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY)) 94 return -EAGAIN; 95 96 data = readl(®s->io); 97 98 return (int)data; 99 } 100 101 static int bcm283x_mu_serial_putc(struct udevice *dev, const char data) 102 { 103 struct bcm283x_mu_priv *priv = dev_get_priv(dev); 104 struct bcm283x_mu_regs *regs = priv->regs; 105 106 /* Wait until there is space in the FIFO */ 107 if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY)) 108 return -EAGAIN; 109 110 /* Send the character */ 111 writel(data, ®s->io); 112 113 return 0; 114 } 115 116 static int bcm283x_mu_serial_pending(struct udevice *dev, bool input) 117 { 118 struct bcm283x_mu_priv *priv = dev_get_priv(dev); 119 struct bcm283x_mu_regs *regs = priv->regs; 120 unsigned int lsr = readl(®s->lsr); 121 122 if (input) { 123 WATCHDOG_RESET(); 124 return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0; 125 } else { 126 return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1; 127 } 128 } 129 130 static const struct dm_serial_ops bcm283x_mu_serial_ops = { 131 .putc = bcm283x_mu_serial_putc, 132 .pending = bcm283x_mu_serial_pending, 133 .getc = bcm283x_mu_serial_getc, 134 .setbrg = bcm283x_mu_serial_setbrg, 135 }; 136 137 #if CONFIG_IS_ENABLED(OF_CONTROL) 138 static const struct udevice_id bcm283x_mu_serial_id[] = { 139 {.compatible = "brcm,bcm2835-aux-uart"}, 140 {} 141 }; 142 143 static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev) 144 { 145 struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev); 146 fdt_addr_t addr; 147 148 addr = dev_get_addr(dev); 149 if (addr == FDT_ADDR_T_NONE) 150 return -EINVAL; 151 152 plat->base = addr; 153 plat->clock = fdtdec_get_int(gd->fdt_blob, dev->of_offset, "clock", 1); 154 plat->skip_init = fdtdec_get_bool(gd->fdt_blob, dev->of_offset, 155 "skip-init"); 156 plat->disabled = false; 157 return 0; 158 } 159 #endif 160 161 U_BOOT_DRIVER(serial_bcm283x_mu) = { 162 .name = "serial_bcm283x_mu", 163 .id = UCLASS_SERIAL, 164 .of_match = of_match_ptr(bcm283x_mu_serial_id), 165 .ofdata_to_platdata = of_match_ptr(bcm283x_mu_serial_ofdata_to_platdata), 166 .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata), 167 .probe = bcm283x_mu_serial_probe, 168 .ops = &bcm283x_mu_serial_ops, 169 .flags = DM_FLAG_PRE_RELOC, 170 .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv), 171 }; 172