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
  15 struct cpm_scc {
  16         u32 gsmrl;
  17         u32 gsmrh;
  18         u16 psmr;
  19         u8 res1[2];
  20         u16 todr;
  21         u16 dsr;
  22         u16 scce;
  23         u8 res2[2];
  24         u16 sccm;
  25         u8 res3;
  26         u8 sccs;
  27         u8 res4[8];
  28 };
  29
  30 struct cpm_smc {
  31         u8 res1[2];
  32         u16 smcmr;
  33         u8 res2[2];
  34         u8 smce;
  35         u8 res3[3];
  36         u8 smcm;
  37         u8 res4[5];
  38 };
  39
  40 struct cpm_param {
  41         u16 rbase;
  42         u16 tbase;
  43         u8 rfcr;
  44         u8 tfcr;
  45 };
  46
  47 struct cpm_bd {
  48         u16 sc;   /* Status and Control */
  49         u16 len;  /* Data length in buffer */
  50         u8 *addr; /* Buffer address in host memory */
  51 };
  52
  53 static void *cpcr;
  54 static struct cpm_param *param;
  55 static struct cpm_smc *smc;
  56 static struct cpm_scc *scc;
  57 struct cpm_bd *tbdf, *rbdf;
  58 static u32 cpm_cmd;
  59 static u8 *muram_start;
  60 static u32 muram_offset;
  61
  62 static void (*do_cmd)(int op);
  63 static void (*enable_port)(void);
  64 static void (*disable_port)(void);
  65
  66 #define CPM_CMD_STOP_TX     4
  67 #define CPM_CMD_RESTART_TX  6
  68 #define CPM_CMD_INIT_RX_TX  0
  69
  70 static void cpm1_cmd(int op)
  71 {
  72         while (in_be16(cpcr) & 1)
  73                 ;
  74
  75         out_be16(cpcr, (op << 8) | cpm_cmd | 1);
  76
  77         while (in_be16(cpcr) & 1)
  78                 ;
  79 }
  80
  81 static void cpm2_cmd(int op)
  82 {
  83         while (in_be32(cpcr) & 0x10000)
  84                 ;
  85
  86         out_be32(cpcr, op | cpm_cmd | 0x10000);
  87
  88         while (in_be32(cpcr) & 0x10000)
  89                 ;
  90 }
  91
  92 static void smc_disable_port(void)
  93 {
  94         do_cmd(CPM_CMD_STOP_TX);
  95         out_be16(&smc->smcmr, in_be16(&smc->smcmr) & ~3);
  96 }
  97
  98 static void scc_disable_port(void)
  99 {
 100         do_cmd(CPM_CMD_STOP_TX);
 101         out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) & ~0x30);
 102 }
 103
 104 static void smc_enable_port(void)
 105 {
 106         out_be16(&smc->smcmr, in_be16(&smc->smcmr) | 3);
 107         do_cmd(CPM_CMD_RESTART_TX);
 108 }
 109
 110 static void scc_enable_port(void)
 111 {
 112         out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) | 0x30);
 113         do_cmd(CPM_CMD_RESTART_TX);
 114 }
 115
 116 static int cpm_serial_open(void)
 117 {
 118         disable_port();
 119
 120         out_8(&param->rfcr, 0x10);
 121         out_8(&param->tfcr, 0x10);
 122
 123         rbdf = (struct cpm_bd *)muram_start;
 124         rbdf->addr = (u8 *)(rbdf + 2);
 125         rbdf->sc = 0xa000;
 126         rbdf->len = 1;
 127
 128         tbdf = rbdf + 1;
 129         tbdf->addr = (u8 *)(rbdf + 2) + 1;
 130         tbdf->sc = 0x2000;
 131         tbdf->len = 1;
 132
 133         sync();
 134         out_be16(&param->rbase, muram_offset);
 135         out_be16(&param->tbase, muram_offset + sizeof(struct cpm_bd));
 136
 137         do_cmd(CPM_CMD_INIT_RX_TX);
 138
 139         enable_port();
 140         return 0;
 141 }
 142
 143 static void cpm_serial_putc(unsigned char c)
 144 {
 145         while (tbdf->sc & 0x8000)
 146                 barrier();
 147
 148         sync();
 149
 150         tbdf->addr[0] = c;
 151         eieio();
 152         tbdf->sc |= 0x8000;
 153 }
 154
 155 static unsigned char cpm_serial_tstc(void)
 156 {
 157         barrier();
 158         return !(rbdf->sc & 0x8000);
 159 }
 160
 161 static unsigned char cpm_serial_getc(void)
 162 {
 163         unsigned char c;
 164
 165         while (!cpm_serial_tstc())
 166                 ;
 167
 168         sync();
 169         c = rbdf->addr[0];
 170         eieio();
 171         rbdf->sc |= 0x8000;
 172
 173         return c;
 174 }
 175
 176 int cpm_console_init(void *devp, struct serial_console_data *scdp)
 177 {
 178         void *reg_virt[2];
 179         int is_smc = 0, is_cpm2 = 0, n;
 180         void *parent, *muram;
 181
 182         if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
 183                 is_smc = 1;
 184         } else if (dt_is_compatible(devp, "fsl,cpm2-scc-uart")) {
 185                 is_cpm2 = 1;
 186         } else if (dt_is_compatible(devp, "fsl,cpm2-smc-uart")) {
 187                 is_cpm2 = 1;
 188                 is_smc = 1;
 189         }
 190
 191         if (is_smc) {
 192                 enable_port = smc_enable_port;
 193                 disable_port = smc_disable_port;
 194         } else {
 195                 enable_port = scc_enable_port;
 196                 disable_port = scc_disable_port;
 197         }
 198
 199         if (is_cpm2)
 200                 do_cmd = cpm2_cmd;
 201         else
 202                 do_cmd = cpm1_cmd;
 203
 204         n = getprop(devp, "fsl,cpm-command", &cpm_cmd, 4);
 205         if (n < 4)
 206                 return -1;
 207
 208         if (dt_get_virtual_reg(devp, reg_virt, 2) < 2)
 209                 return -1;
 210
 211         if (is_smc)
 212                 smc = reg_virt[0];
 213         else
 214                 scc = reg_virt[0];
 215
 216         param = reg_virt[1];
 217
 218         parent = get_parent(devp);
 219         if (!parent)
 220                 return -1;
 221
 222         if (dt_get_virtual_reg(parent, &cpcr, 1) < 1)
 223                 return -1;
 224
 225         muram = finddevice("/soc/cpm/muram/data");
 226         if (!muram)
 227                 return -1;
 228
 229         /* For bootwrapper-compatible device trees, we assume that the first
 230          * entry has at least 18 bytes, and that #address-cells/#data-cells
 231          * is one for both parent and child.
 232          */
 233
 234         if (dt_get_virtual_reg(muram, (void **)&muram_start, 1) < 1)
 235                 return -1;
 236
 237         n = getprop(muram, "reg", &muram_offset, 4);
 238         if (n < 4)
 239                 return -1;
 240
 241         scdp->open = cpm_serial_open;
 242         scdp->putc = cpm_serial_putc;
 243         scdp->getc = cpm_serial_getc;
 244         scdp->tstc = cpm_serial_tstc;
 245
 246         return 0;
 247 }