drivers/serial/serial_linflexuart.c

   1 /*
   2  * (C) Copyright 2013-2016 Freescale Semiconductor, Inc.
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <dm.h>
   9 #include <errno.h>
  10 #include <watchdog.h>
  11 #include <asm/io.h>
  12 #include <serial.h>
  13 #include <linux/compiler.h>
  14 #include <asm/arch/imx-regs.h>
  15 #include <asm/arch/clock.h>
  16
  17 #define US1_TDRE            (1 << 7)
  18 #define US1_RDRF            (1 << 5)
  19 #define UC2_TE              (1 << 3)
  20 #define LINCR1_INIT         (1 << 0)
  21 #define LINCR1_MME          (1 << 4)
  22 #define LINCR1_BF           (1 << 7)
  23 #define LINSR_LINS_INITMODE (0x00001000)
  24 #define LINSR_LINS_MASK     (0x0000F000)
  25 #define UARTCR_UART         (1 << 0)
  26 #define UARTCR_WL0          (1 << 1)
  27 #define UARTCR_PCE          (1 << 2)
  28 #define UARTCR_PC0          (1 << 3)
  29 #define UARTCR_TXEN         (1 << 4)
  30 #define UARTCR_RXEN         (1 << 5)
  31 #define UARTCR_PC1          (1 << 6)
  32 #define UARTSR_DTF          (1 << 1)
  33 #define UARTSR_DRF          (1 << 2)
  34 #define UARTSR_RMB          (1 << 9)
  35
  36 DECLARE_GLOBAL_DATA_PTR;
  37
  38 #ifndef CONFIG_DM_SERIAL
  39 #error "The linflex serial driver does not have non-DM support."
  40 #endif
  41
  42 static void _linflex_serial_setbrg(struct linflex_fsl *base, int baudrate)
  43 {
  44         u32 clk = mxc_get_clock(MXC_UART_CLK);
  45         u32 ibr, fbr;
  46
  47         if (!baudrate)
  48                 baudrate = CONFIG_BAUDRATE;
  49
  50         ibr = (u32) (clk / (16 * gd->baudrate));
  51         fbr = (u32) (clk % (16 * gd->baudrate)) * 16;
  52
  53         __raw_writel(ibr, &base->linibrr);
  54         __raw_writel(fbr, &base->linfbrr);
  55 }
  56
  57 static int _linflex_serial_getc(struct linflex_fsl *base)
  58 {
  59         char c;
  60
  61         if (!(__raw_readb(&base->uartsr) & UARTSR_DRF))
  62                 return -EAGAIN;
  63
  64         if (!(__raw_readl(&base->uartsr) & UARTSR_RMB))
  65                 return -EAGAIN;
  66
  67         c = __raw_readl(&base->bdrm);
  68         __raw_writeb((__raw_readb(&base->uartsr) | (UARTSR_DRF | UARTSR_RMB)),
  69                      &base->uartsr);
  70         return c;
  71 }
  72
  73 static int _linflex_serial_putc(struct linflex_fsl *base, const char c)
  74 {
  75         __raw_writeb(c, &base->bdrl);
  76
  77
  78         if (!(__raw_readb(&base->uartsr) & UARTSR_DTF))
  79                 return -EAGAIN;
  80
  81         __raw_writeb((__raw_readb(&base->uartsr) | UARTSR_DTF), &base->uartsr);
  82
  83         return 0;
  84 }
  85
  86 /*
  87  * Initialise the serial port with the given baudrate. The settings
  88  * are always 8 data bits, no parity, 1 stop bit, no start bits.
  89  */
  90 static int _linflex_serial_init(struct linflex_fsl *base)
  91 {
  92         volatile u32 ctrl;
  93
  94         /* set the Linflex in master mode amd activate by-pass filter */
  95         ctrl = LINCR1_BF | LINCR1_MME;
  96         __raw_writel(ctrl, &base->lincr1);
  97
  98         /* init mode */
  99         ctrl |= LINCR1_INIT;
 100         __raw_writel(ctrl, &base->lincr1);
 101
 102         /* waiting for init mode entry - TODO: add a timeout */
 103         while ((__raw_readl(&base->linsr) & LINSR_LINS_MASK) !=
 104                LINSR_LINS_INITMODE);
 105
 106         /* set UART bit to allow writing other bits */
 107         __raw_writel(UARTCR_UART, &base->uartcr);
 108
 109         /* provide data bits, parity, stop bit, etc */
 110         serial_setbrg();
 111
 112         /* 8 bit data, no parity, Tx and Rx enabled, UART mode */
 113         __raw_writel(UARTCR_PC1 | UARTCR_RXEN | UARTCR_TXEN | UARTCR_PC0
 114                      | UARTCR_WL0 | UARTCR_UART, &base->uartcr);
 115
 116         ctrl = __raw_readl(&base->lincr1);
 117         ctrl &= ~LINCR1_INIT;
 118         __raw_writel(ctrl, &base->lincr1);      /* end init mode */
 119
 120         return 0;
 121 }
 122
 123 struct linflex_serial_platdata {
 124         struct linflex_fsl *base_addr;
 125         u8 port_id; /* do we need this? */
 126 };
 127
 128 struct linflex_serial_priv {
 129         struct linflex_fsl *lfuart;
 130 };
 131
 132 int linflex_serial_setbrg(struct udevice *dev, int baudrate)
 133 {
 134         struct linflex_serial_priv *priv = dev_get_priv(dev);
 135
 136         _linflex_serial_setbrg(priv->lfuart, baudrate);
 137
 138         return 0;
 139 }
 140
 141 static int linflex_serial_getc(struct udevice *dev)
 142 {
 143         struct linflex_serial_priv *priv = dev_get_priv(dev);
 144
 145         return _linflex_serial_getc(priv->lfuart);
 146 }
 147
 148 static int linflex_serial_putc(struct udevice *dev, const char ch)
 149 {
 150
 151         struct linflex_serial_priv *priv = dev_get_priv(dev);
 152
 153         return _linflex_serial_putc(priv->lfuart, ch);
 154 }
 155
 156 static int linflex_serial_pending(struct udevice *dev, bool input)
 157 {
 158         struct linflex_serial_priv *priv = dev_get_priv(dev);
 159         uint32_t uartsr = __raw_readl(&priv->lfuart->uartsr);
 160
 161         if (input)
 162                 return ((uartsr & UARTSR_DRF) && (uartsr & UARTSR_RMB)) ? 1 : 0;
 163         else
 164                 return uartsr & UARTSR_DTF ? 0 : 1;
 165 }
 166
 167 static void linflex_serial_init_internal(struct linflex_fsl *lfuart)
 168 {
 169         _linflex_serial_init(lfuart);
 170         _linflex_serial_setbrg(lfuart, CONFIG_BAUDRATE);
 171         return;
 172 }
 173
 174 static int linflex_serial_probe(struct udevice *dev)
 175 {
 176         struct linflex_serial_platdata *plat = dev->platdata;
 177         struct linflex_serial_priv *priv = dev_get_priv(dev);
 178
 179         priv->lfuart = (struct linflex_fsl *)plat->base_addr;
 180         linflex_serial_init_internal(priv->lfuart);
 181
 182         return 0;
 183 }
 184
 185 static const struct dm_serial_ops linflex_serial_ops = {
 186         .putc = linflex_serial_putc,
 187         .pending = linflex_serial_pending,
 188         .getc = linflex_serial_getc,
 189         .setbrg = linflex_serial_setbrg,
 190 };
 191
 192 U_BOOT_DRIVER(serial_linflex) = {
 193         .name   = "serial_linflex",
 194         .id     = UCLASS_SERIAL,
 195         .probe = linflex_serial_probe,
 196         .ops    = &linflex_serial_ops,
 197         .flags = DM_FLAG_PRE_RELOC,
 198         .priv_auto_alloc_size   = sizeof(struct linflex_serial_priv),
 199 };
 200
 201 #ifdef CONFIG_DEBUG_UART_LINFLEXUART
 202
 203 #include <debug_uart.h>
 204
 205
 206 static inline void _debug_uart_init(void)
 207 {
 208         struct linflex_fsl *base = (struct linflex_fsl *)CONFIG_DEBUG_UART_BASE;
 209
 210         linflex_serial_init_internal(base);
 211 }
 212
 213 static inline void _debug_uart_putc(int ch)
 214 {
 215         struct linflex_fsl *base = (struct linflex_fsl *)CONFIG_DEBUG_UART_BASE;
 216
 217         /* XXX: Is this OK? Should this use the non-DM version? */
 218         _linflex_serial_putc(base, ch);
 219 }
 220
 221 DEBUG_UART_FUNCS
 222
 223 #endif /* CONFIG_DEBUG_UART_LINFLEXUART */