arch/powerpc/boot/cpm-serial.c

   1 /*
   2  * CPM serial console support.
   3  *
   4  * Copyright 2007 Freescale Semiconductor, Inc.
   5  * Author: Scott Wood <scottwood@freescale.com>
   6  *
   7  * It is assumed that the firmware (or the platform file) has already set
   8  * up the port.
   9  */
  10
  11 #include "types.h"
  12 #include "io.h"
  13 #include "ops.h"
  14 #include "page.h"
  15
  16 struct cpm_scc {
  17         u32 gsmrl;
  18         u32 gsmrh;
  19         u16 psmr;
  20         u8 res1[2];
  21         u16 todr;
  22         u16 dsr;
  23         u16 scce;
  24         u8 res2[2];
  25         u16 sccm;
  26         u8 res3;
  27         u8 sccs;
  28         u8 res4[8];
  29 };
  30
  31 struct cpm_smc {
  32         u8 res1[2];
  33         u16 smcmr;
  34         u8 res2[2];
  35         u8 smce;
  36         u8 res3[3];
  37         u8 smcm;
  38         u8 res4[5];
  39 };
  40
  41 struct cpm_param {
  42         u16 rbase;
  43         u16 tbase;
  44         u8 rfcr;
  45         u8 tfcr;
  46         u16 mrblr;
  47         u32 rstate;
  48         u8 res1[4];
  49         u16 rbptr;
  50         u8 res2[6];
  51         u32 tstate;
  52         u8 res3[4];
  53         u16 tbptr;
  54         u8 res4[6];
  55         u16 maxidl;
  56         u16 idlc;
  57         u16 brkln;
  58         u16 brkec;
  59         u16 brkcr;
  60         u16 rmask;
  61         u8 res5[4];
  62 };
  63
  64 struct cpm_bd {
  65         u16 sc;   /* Status and Control */
  66         u16 len;  /* Data length in buffer */
  67         u8 *addr; /* Buffer address in host memory */
  68 };
  69
  70 static void *cpcr;
  71 static struct cpm_param *param;
  72 static struct cpm_smc *smc;
  73 static struct cpm_scc *scc;
  74 static struct cpm_bd *tbdf, *rbdf;
  75 static u32 cpm_cmd;
  76 static void *cbd_addr;
  77 static u32 cbd_offset;
  78
  79 static void (*do_cmd)(int op);
  80 static void (*enable_port)(void);
  81 static void (*disable_port)(void);
  82
  83 #define CPM_CMD_STOP_TX     4
  84 #define CPM_CMD_RESTART_TX  6
  85 #define CPM_CMD_INIT_RX_TX  0
  86
  87 static void cpm1_cmd(int op)
  88 {
  89         while (in_be16(cpcr) & 1)
  90                 ;
  91
  92         out_be16(cpcr, (op << 8) | cpm_cmd | 1);
  93
  94         while (in_be16(cpcr) & 1)
  95                 ;
  96 }
  97
  98 static void cpm2_cmd(int op)
  99 {
 100         while (in_be32(cpcr) & 0x10000)
 101                 ;
 102
 103         out_be32(cpcr, op | cpm_cmd | 0x10000);
 104
 105         while (in_be32(cpcr) & 0x10000)
 106                 ;
 107 }
 108
 109 static void smc_disable_port(void)
 110 {
 111         do_cmd(CPM_CMD_STOP_TX);
 112         out_be16(&smc->smcmr, in_be16(&smc->smcmr) & ~3);
 113 }
 114
 115 static void scc_disable_port(void)
 116 {
 117         do_cmd(CPM_CMD_STOP_TX);
 118         out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) & ~0x30);
 119 }
 120
 121 static void smc_enable_port(void)
 122 {
 123         out_be16(&smc->smcmr, in_be16(&smc->smcmr) | 3);
 124         do_cmd(CPM_CMD_RESTART_TX);
 125 }
 126
 127 static void scc_enable_port(void)
 128 {
 129         out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) | 0x30);
 130         do_cmd(CPM_CMD_RESTART_TX);
 131 }
 132
 133 static int cpm_serial_open(void)
 134 {
 135         disable_port();
 136
 137         out_8(&param->rfcr, 0x10);
 138         out_8(&param->tfcr, 0x10);
 139         out_be16(&param->mrblr, 1);
 140         out_be16(&param->maxidl, 0);
 141         out_be16(&param->brkec, 0);
 142         out_be16(&param->brkln, 0);
 143         out_be16(&param->brkcr, 0);
 144
 145         rbdf = cbd_addr;
 146         rbdf->addr = (u8 *)rbdf - 1;
 147         rbdf->sc = 0xa000;
 148         rbdf->len = 1;
 149
 150         tbdf = rbdf + 1;
 151         tbdf->addr = (u8 *)rbdf - 2;
 152         tbdf->sc = 0x2000;
 153         tbdf->len = 1;
 154
 155         sync();
 156         out_be16(&param->rbase, cbd_offset);
 157         out_be16(&param->tbase, cbd_offset + sizeof(struct cpm_bd));
 158
 159         do_cmd(CPM_CMD_INIT_RX_TX);
 160
 161         enable_port();
 162         return 0;
 163 }
 164
 165 static void cpm_serial_putc(unsigned char c)
 166 {
 167         while (tbdf->sc & 0x8000)
 168                 barrier();
 169
 170         sync();
 171
 172         tbdf->addr[0] = c;
 173         eieio();
 174         tbdf->sc |= 0x8000;
 175 }
 176
 177 static unsigned char cpm_serial_tstc(void)
 178 {
 179         barrier();
 180         return !(rbdf->sc & 0x8000);
 181 }
 182
 183 static unsigned char cpm_serial_getc(void)
 184 {
 185         unsigned char c;
 186
 187         while (!cpm_serial_tstc())
 188                 ;
 189
 190         sync();
 191         c = rbdf->addr[0];
 192         eieio();
 193         rbdf->sc |= 0x8000;
 194
 195         return c;
 196 }
 197
 198 int cpm_console_init(void *devp, struct serial_console_data *scdp)
 199 {
 200         void *vreg[2];
 201         u32 reg[2];
 202         int is_smc = 0, is_cpm2 = 0;
 203         void *parent, *muram;
 204         void *muram_addr;
 205         unsigned long muram_offset, muram_size;
 206
 207         if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
 208                 is_smc = 1;
 209         } else if (dt_is_compatible(devp, "fsl,cpm2-scc-uart")) {
 210                 is_cpm2 = 1;
 211         } else if (dt_is_compatible(devp, "fsl,cpm2-smc-uart")) {
 212                 is_cpm2 = 1;
 213                 is_smc = 1;
 214         }
 215
 216         if (is_smc) {
 217                 enable_port = smc_enable_port;
 218                 disable_port = smc_disable_port;
 219         } else {
 220                 enable_port = scc_enable_port;
 221                 disable_port = scc_disable_port;
 222         }
 223
 224         if (is_cpm2)
 225                 do_cmd = cpm2_cmd;
 226         else
 227                 do_cmd = cpm1_cmd;
 228
 229         if (getprop(devp, "fsl,cpm-command", &cpm_cmd, 4) < 4)
 230                 return -1;
 231
 232         if (dt_get_virtual_reg(devp, vreg, 2) < 2)
 233                 return -1;
 234
 235         if (is_smc)
 236                 smc = vreg[0];
 237         else
 238                 scc = vreg[0];
 239
 240         param = vreg[1];
 241
 242         parent = get_parent(devp);
 243         if (!parent)
 244                 return -1;
 245
 246         if (dt_get_virtual_reg(parent, &cpcr, 1) < 1)
 247                 return -1;
 248
 249         muram = finddevice("/soc/cpm/muram/data");
 250         if (!muram)
 251                 return -1;
 252
 253         /* For bootwrapper-compatible device trees, we assume that the first
 254          * entry has at least 128 bytes, and that #address-cells/#data-cells
 255          * is one for both parent and child.
 256          */
 257
 258         if (dt_get_virtual_reg(muram, &muram_addr, 1) < 1)
 259                 return -1;
 260
 261         if (getprop(muram, "reg", reg, 8) < 8)
 262                 return -1;
 263
 264         muram_offset = reg[0];
 265         muram_size = reg[1];
 266
 267         /* Store the buffer descriptors at the end of the first muram chunk.
 268          * For SMC ports on CPM2-based platforms, relocate the parameter RAM
 269          * just before the buffer descriptors.
 270          */
 271
 272         cbd_offset = muram_offset + muram_size - 2 * sizeof(struct cpm_bd);
 273
 274         if (is_cpm2 && is_smc) {
 275                 u16 *smc_base = (u16 *)param;
 276                 u16 pram_offset;
 277
 278                 pram_offset = cbd_offset - 64;
 279                 pram_offset = _ALIGN_DOWN(pram_offset, 64);
 280
 281                 disable_port();
 282                 out_be16(smc_base, pram_offset);
 283                 param = muram_addr - muram_offset + pram_offset;
 284         }
 285
 286         cbd_addr = muram_addr - muram_offset + cbd_offset;
 287
 288         scdp->open = cpm_serial_open;
 289         scdp->putc = cpm_serial_putc;
 290         scdp->getc = cpm_serial_getc;
 291         scdp->tstc = cpm_serial_tstc;
 292
 293         return 0;
 294 }