arch/x86/kernel/early_printk_mrst.c

   1 /*
   2  * early_printk_mrst.c - early consoles for Intel MID platforms
   3  *
   4  * Copyright (c) 2008-2010, Intel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; version 2
   9  * of the License.
  10  */
  11
  12 /*
  13  * This file implements two early consoles named mrst and hsu.
  14  * mrst is based on Maxim3110 spi-uart device, it exists in both
  15  * Moorestown and Medfield platforms, while hsu is based on a High
  16  * Speed UART device which only exists in the Medfield platform
  17  */
  18
  19 #include <linux/serial_reg.h>
  20 #include <linux/serial_mfd.h>
  21 #include <linux/kmsg_dump.h>
  22 #include <linux/console.h>
  23 #include <linux/kernel.h>
  24 #include <linux/delay.h>
  25 #include <linux/init.h>
  26 #include <linux/io.h>
  27
  28 #include <asm/fixmap.h>
  29 #include <asm/pgtable.h>
  30 #include <asm/mrst.h>
  31
  32 #define MRST_SPI_TIMEOUT                0x200000
  33 #define MRST_REGBASE_SPI0               0xff128000
  34 #define MRST_REGBASE_SPI1               0xff128400
  35 #define MRST_CLK_SPI0_REG               0xff11d86c
  36
  37 /* Bit fields in CTRLR0 */
  38 #define SPI_DFS_OFFSET                  0
  39
  40 #define SPI_FRF_OFFSET                  4
  41 #define SPI_FRF_SPI                     0x0
  42 #define SPI_FRF_SSP                     0x1
  43 #define SPI_FRF_MICROWIRE               0x2
  44 #define SPI_FRF_RESV                    0x3
  45
  46 #define SPI_MODE_OFFSET                 6
  47 #define SPI_SCPH_OFFSET                 6
  48 #define SPI_SCOL_OFFSET                 7
  49 #define SPI_TMOD_OFFSET                 8
  50 #define SPI_TMOD_TR                     0x0             /* xmit & recv */
  51 #define SPI_TMOD_TO                     0x1             /* xmit only */
  52 #define SPI_TMOD_RO                     0x2             /* recv only */
  53 #define SPI_TMOD_EPROMREAD              0x3             /* eeprom read mode */
  54
  55 #define SPI_SLVOE_OFFSET                10
  56 #define SPI_SRL_OFFSET                  11
  57 #define SPI_CFS_OFFSET                  12
  58
  59 /* Bit fields in SR, 7 bits */
  60 #define SR_MASK                         0x7f            /* cover 7 bits */
  61 #define SR_BUSY                         (1 << 0)
  62 #define SR_TF_NOT_FULL                  (1 << 1)
  63 #define SR_TF_EMPT                      (1 << 2)
  64 #define SR_RF_NOT_EMPT                  (1 << 3)
  65 #define SR_RF_FULL                      (1 << 4)
  66 #define SR_TX_ERR                       (1 << 5)
  67 #define SR_DCOL                         (1 << 6)
  68
  69 struct dw_spi_reg {
  70         u32     ctrl0;
  71         u32     ctrl1;
  72         u32     ssienr;
  73         u32     mwcr;
  74         u32     ser;
  75         u32     baudr;
  76         u32     txfltr;
  77         u32     rxfltr;
  78         u32     txflr;
  79         u32     rxflr;
  80         u32     sr;
  81         u32     imr;
  82         u32     isr;
  83         u32     risr;
  84         u32     txoicr;
  85         u32     rxoicr;
  86         u32     rxuicr;
  87         u32     msticr;
  88         u32     icr;
  89         u32     dmacr;
  90         u32     dmatdlr;
  91         u32     dmardlr;
  92         u32     idr;
  93         u32     version;
  94
  95         /* Currently operates as 32 bits, though only the low 16 bits matter */
  96         u32     dr;
  97 } __packed;
  98
  99 #define dw_readl(dw, name)              __raw_readl(&(dw)->name)
 100 #define dw_writel(dw, name, val)        __raw_writel((val), &(dw)->name)
 101
 102 /* Default use SPI0 register for mrst, we will detect Penwell and use SPI1 */
 103 static unsigned long mrst_spi_paddr = MRST_REGBASE_SPI0;
 104
 105 static u32 *pclk_spi0;
 106 /* Always contains an accessable address, start with 0 */
 107 static struct dw_spi_reg *pspi;
 108
 109 static struct kmsg_dumper dw_dumper;
 110 static int dumper_registered;
 111
 112 static void dw_kmsg_dump(struct kmsg_dumper *dumper,
 113                         enum kmsg_dump_reason reason,
 114                         const char *s1, unsigned long l1,
 115                         const char *s2, unsigned long l2)
 116 {
 117         int i;
 118
 119         /* When run to this, we'd better re-init the HW */
 120         mrst_early_console_init();
 121
 122         for (i = 0; i < l1; i++)
 123                 early_mrst_console.write(&early_mrst_console, s1 + i, 1);
 124         for (i = 0; i < l2; i++)
 125                 early_mrst_console.write(&early_mrst_console, s2 + i, 1);
 126 }
 127
 128 /* Set the ratio rate to 115200, 8n1, IRQ disabled */
 129 static void max3110_write_config(void)
 130 {
 131         u16 config;
 132
 133         config = 0xc001;
 134         dw_writel(pspi, dr, config);
 135 }
 136
 137 /* Translate char to a eligible word and send to max3110 */
 138 static void max3110_write_data(char c)
 139 {
 140         u16 data;
 141
 142         data = 0x8000 | c;
 143         dw_writel(pspi, dr, data);
 144 }
 145
 146 void mrst_early_console_init(void)
 147 {
 148         u32 ctrlr0 = 0;
 149         u32 spi0_cdiv;
 150         u32 freq; /* Freqency info only need be searched once */
 151
 152         /* Base clk is 100 MHz, the actual clk = 100M / (clk_divider + 1) */
 153         pclk_spi0 = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE,
 154                                                         MRST_CLK_SPI0_REG);
 155         spi0_cdiv = ((*pclk_spi0) & 0xe00) >> 9;
 156         freq = 100000000 / (spi0_cdiv + 1);
 157
 158         if (mrst_identify_cpu() == MRST_CPU_CHIP_PENWELL)
 159                 mrst_spi_paddr = MRST_REGBASE_SPI1;
 160
 161         pspi = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE,
 162                                                 mrst_spi_paddr);
 163
 164         /* Disable SPI controller */
 165         dw_writel(pspi, ssienr, 0);
 166
 167         /* Set control param, 8 bits, transmit only mode */
 168         ctrlr0 = dw_readl(pspi, ctrl0);
 169
 170         ctrlr0 &= 0xfcc0;
 171         ctrlr0 |= 0xf | (SPI_FRF_SPI << SPI_FRF_OFFSET)
 172                       | (SPI_TMOD_TO << SPI_TMOD_OFFSET);
 173         dw_writel(pspi, ctrl0, ctrlr0);
 174
 175         /*
 176          * Change the spi0 clk to comply with 115200 bps, use 100000 to
 177          * calculate the clk dividor to make the clock a little slower
 178          * than real baud rate.
 179          */
 180         dw_writel(pspi, baudr, freq/100000);
 181
 182         /* Disable all INT for early phase */
 183         dw_writel(pspi, imr, 0x0);
 184
 185         /* Set the cs to spi-uart */
 186         dw_writel(pspi, ser, 0x2);
 187
 188         /* Enable the HW, the last step for HW init */
 189         dw_writel(pspi, ssienr, 0x1);
 190
 191         /* Set the default configuration */
 192         max3110_write_config();
 193
 194         /* Register the kmsg dumper */
 195         if (!dumper_registered) {
 196                 dw_dumper.dump = dw_kmsg_dump;
 197                 kmsg_dump_register(&dw_dumper);
 198                 dumper_registered = 1;
 199         }
 200 }
 201
 202 /* Slave select should be called in the read/write function */
 203 static void early_mrst_spi_putc(char c)
 204 {
 205         unsigned int timeout;
 206         u32 sr;
 207
 208         timeout = MRST_SPI_TIMEOUT;
 209         /* Early putc needs to make sure the TX FIFO is not full */
 210         while (--timeout) {
 211                 sr = dw_readl(pspi, sr);
 212                 if (!(sr & SR_TF_NOT_FULL))
 213                         cpu_relax();
 214                 else
 215                         break;
 216         }
 217
 218         if (!timeout)
 219                 pr_warning("MRST earlycon: timed out\n");
 220         else
 221                 max3110_write_data(c);
 222 }
 223
 224 /* Early SPI only uses polling mode */
 225 static void early_mrst_spi_write(struct console *con, const char *str, unsigned n)
 226 {
 227         int i;
 228
 229         for (i = 0; i < n && *str; i++) {
 230                 if (*str == '\n')
 231                         early_mrst_spi_putc('\r');
 232                 early_mrst_spi_putc(*str);
 233                 str++;
 234         }
 235 }
 236
 237 struct console early_mrst_console = {
 238         .name =         "earlymrst",
 239         .write =        early_mrst_spi_write,
 240         .flags =        CON_PRINTBUFFER,
 241         .index =        -1,
 242 };
 243
 244 /*
 245  * Following is the early console based on Medfield HSU (High
 246  * Speed UART) device.
 247  */
 248 #define HSU_PORT2_PADDR         0xffa28180
 249
 250 static void __iomem *phsu;
 251
 252 void hsu_early_console_init(void)
 253 {
 254         u8 lcr;
 255
 256         phsu = (void *)set_fixmap_offset_nocache(FIX_EARLYCON_MEM_BASE,
 257                                                         HSU_PORT2_PADDR);
 258
 259         /* Disable FIFO */
 260         writeb(0x0, phsu + UART_FCR);
 261
 262         /* Set to default 115200 bps, 8n1 */
 263         lcr = readb(phsu + UART_LCR);
 264         writeb((0x80 | lcr), phsu + UART_LCR);
 265         writeb(0x18, phsu + UART_DLL);
 266         writeb(lcr,  phsu + UART_LCR);
 267         writel(0x3600, phsu + UART_MUL*4);
 268
 269         writeb(0x8, phsu + UART_MCR);
 270         writeb(0x7, phsu + UART_FCR);
 271         writeb(0x3, phsu + UART_LCR);
 272
 273         /* Clear IRQ status */
 274         readb(phsu + UART_LSR);
 275         readb(phsu + UART_RX);
 276         readb(phsu + UART_IIR);
 277         readb(phsu + UART_MSR);
 278
 279         /* Enable FIFO */
 280         writeb(0x7, phsu + UART_FCR);
 281 }
 282
 283 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
 284
 285 static void early_hsu_putc(char ch)
 286 {
 287         unsigned int timeout = 10000; /* 10ms */
 288         u8 status;
 289
 290         while (--timeout) {
 291                 status = readb(phsu + UART_LSR);
 292                 if (status & BOTH_EMPTY)
 293                         break;
 294                 udelay(1);
 295         }
 296
 297         /* Only write the char when there was no timeout */
 298         if (timeout)
 299                 writeb(ch, phsu + UART_TX);
 300 }
 301
 302 static void early_hsu_write(struct console *con, const char *str, unsigned n)
 303 {
 304         int i;
 305
 306         for (i = 0; i < n && *str; i++) {
 307                 if (*str == '\n')
 308                         early_hsu_putc('\r');
 309                 early_hsu_putc(*str);
 310                 str++;
 311         }
 312 }
 313
 314 struct console early_hsu_console = {
 315         .name =         "earlyhsu",
 316         .write =        early_hsu_write,
 317         .flags =        CON_PRINTBUFFER,
 318         .index =        -1,
 319 };