powerpc/boot/cpm-serial.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * CPM serial console support.
0004  *
0005  * Copyright 2007 Freescale Semiconductor, Inc.
0006  * Author: Scott Wood <scottwood@freescale.com>
0007  *
0008  * It is assumed that the firmware (or the platform file) has already set
0009  * up the port.
0010  */
0011
0012 #include "types.h"
0013 #include "io.h"
0014 #include "ops.h"
0015 #include "page.h"
0016
0017 struct cpm_scc {
0018     u32 gsmrl;
0019     u32 gsmrh;
0020     u16 psmr;
0021     u8 res1[2];
0022     u16 todr;
0023     u16 dsr;
0024     u16 scce;
0025     u8 res2[2];
0026     u16 sccm;
0027     u8 res3;
0028     u8 sccs;
0029     u8 res4[8];
0030 };
0031
0032 struct cpm_smc {
0033     u8 res1[2];
0034     u16 smcmr;
0035     u8 res2[2];
0036     u8 smce;
0037     u8 res3[3];
0038     u8 smcm;
0039     u8 res4[5];
0040 };
0041
0042 struct cpm_param {
0043     u16 rbase;
0044     u16 tbase;
0045     u8 rfcr;
0046     u8 tfcr;
0047     u16 mrblr;
0048     u32 rstate;
0049     u8 res1[4];
0050     u16 rbptr;
0051     u8 res2[6];
0052     u32 tstate;
0053     u8 res3[4];
0054     u16 tbptr;
0055     u8 res4[6];
0056     u16 maxidl;
0057     u16 idlc;
0058     u16 brkln;
0059     u16 brkec;
0060     u16 brkcr;
0061     u16 rmask;
0062     u8 res5[4];
0063 };
0064
0065 struct cpm_bd {
0066     u16 sc;   /* Status and Control */
0067     u16 len;  /* Data length in buffer */
0068     u8 *addr; /* Buffer address in host memory */
0069 };
0070
0071 static void *cpcr;
0072 static struct cpm_param *param;
0073 static struct cpm_smc *smc;
0074 static struct cpm_scc *scc;
0075 static struct cpm_bd *tbdf, *rbdf;
0076 static u32 cpm_cmd;
0077 static void *cbd_addr;
0078 static u32 cbd_offset;
0079
0080 static void (*do_cmd)(int op);
0081 static void (*enable_port)(void);
0082 static void (*disable_port)(void);
0083
0084 #define CPM_CMD_STOP_TX     4
0085 #define CPM_CMD_RESTART_TX  6
0086 #define CPM_CMD_INIT_RX_TX  0
0087
0088 static void cpm1_cmd(int op)
0089 {
0090     while (in_be16(cpcr) & 1)
0091         ;
0092
0093     out_be16(cpcr, (op << 8) | cpm_cmd | 1);
0094
0095     while (in_be16(cpcr) & 1)
0096         ;
0097 }
0098
0099 static void cpm2_cmd(int op)
0100 {
0101     while (in_be32(cpcr) & 0x10000)
0102         ;
0103
0104     out_be32(cpcr, op | cpm_cmd | 0x10000);
0105
0106     while (in_be32(cpcr) & 0x10000)
0107         ;
0108 }
0109
0110 static void smc_disable_port(void)
0111 {
0112     do_cmd(CPM_CMD_STOP_TX);
0113     out_be16(&smc->smcmr, in_be16(&smc->smcmr) & ~3);
0114 }
0115
0116 static void scc_disable_port(void)
0117 {
0118     do_cmd(CPM_CMD_STOP_TX);
0119     out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) & ~0x30);
0120 }
0121
0122 static void smc_enable_port(void)
0123 {
0124     out_be16(&smc->smcmr, in_be16(&smc->smcmr) | 3);
0125     do_cmd(CPM_CMD_RESTART_TX);
0126 }
0127
0128 static void scc_enable_port(void)
0129 {
0130     out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) | 0x30);
0131     do_cmd(CPM_CMD_RESTART_TX);
0132 }
0133
0134 static int cpm_serial_open(void)
0135 {
0136     disable_port();
0137
0138     out_8(&param->rfcr, 0x10);
0139     out_8(&param->tfcr, 0x10);
0140     out_be16(&param->mrblr, 1);
0141     out_be16(&param->maxidl, 0);
0142     out_be16(&param->brkec, 0);
0143     out_be16(&param->brkln, 0);
0144     out_be16(&param->brkcr, 0);
0145
0146     rbdf = cbd_addr;
0147     rbdf->addr = (u8 *)rbdf - 1;
0148     rbdf->sc = 0xa000;
0149     rbdf->len = 1;
0150
0151     tbdf = rbdf + 1;
0152     tbdf->addr = (u8 *)rbdf - 2;
0153     tbdf->sc = 0x2000;
0154     tbdf->len = 1;
0155
0156     sync();
0157     out_be16(&param->rbase, cbd_offset);
0158     out_be16(&param->tbase, cbd_offset + sizeof(struct cpm_bd));
0159
0160     do_cmd(CPM_CMD_INIT_RX_TX);
0161
0162     enable_port();
0163     return 0;
0164 }
0165
0166 static void cpm_serial_putc(unsigned char c)
0167 {
0168     while (tbdf->sc & 0x8000)
0169         barrier();
0170
0171     sync();
0172
0173     tbdf->addr[0] = c;
0174     eieio();
0175     tbdf->sc |= 0x8000;
0176 }
0177
0178 static unsigned char cpm_serial_tstc(void)
0179 {
0180     barrier();
0181     return !(rbdf->sc & 0x8000);
0182 }
0183
0184 static unsigned char cpm_serial_getc(void)
0185 {
0186     unsigned char c;
0187
0188     while (!cpm_serial_tstc())
0189         ;
0190
0191     sync();
0192     c = rbdf->addr[0];
0193     eieio();
0194     rbdf->sc |= 0x8000;
0195
0196     return c;
0197 }
0198
0199 int cpm_console_init(void *devp, struct serial_console_data *scdp)
0200 {
0201     void *vreg[2];
0202     u32 reg[2];
0203     int is_smc = 0, is_cpm2 = 0;
0204     void *parent, *muram;
0205     void *muram_addr;
0206     unsigned long muram_offset, muram_size;
0207
0208     if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
0209         is_smc = 1;
0210     } else if (dt_is_compatible(devp, "fsl,cpm2-scc-uart")) {
0211         is_cpm2 = 1;
0212     } else if (dt_is_compatible(devp, "fsl,cpm2-smc-uart")) {
0213         is_cpm2 = 1;
0214         is_smc = 1;
0215     }
0216
0217     if (is_smc) {
0218         enable_port = smc_enable_port;
0219         disable_port = smc_disable_port;
0220     } else {
0221         enable_port = scc_enable_port;
0222         disable_port = scc_disable_port;
0223     }
0224
0225     if (is_cpm2)
0226         do_cmd = cpm2_cmd;
0227     else
0228         do_cmd = cpm1_cmd;
0229
0230     if (getprop(devp, "fsl,cpm-command", &cpm_cmd, 4) < 4)
0231         return -1;
0232
0233     if (dt_get_virtual_reg(devp, vreg, 2) < 2)
0234         return -1;
0235
0236     if (is_smc)
0237         smc = vreg[0];
0238     else
0239         scc = vreg[0];
0240
0241     param = vreg[1];
0242
0243     parent = get_parent(devp);
0244     if (!parent)
0245         return -1;
0246
0247     if (dt_get_virtual_reg(parent, &cpcr, 1) < 1)
0248         return -1;
0249
0250     muram = finddevice("/soc/cpm/muram/data");
0251     if (!muram)
0252         return -1;
0253
0254     /* For bootwrapper-compatible device trees, we assume that the first
0255      * entry has at least 128 bytes, and that #address-cells/#data-cells
0256      * is one for both parent and child.
0257      */
0258
0259     if (dt_get_virtual_reg(muram, &muram_addr, 1) < 1)
0260         return -1;
0261
0262     if (getprop(muram, "reg", reg, 8) < 8)
0263         return -1;
0264
0265     muram_offset = reg[0];
0266     muram_size = reg[1];
0267
0268     /* Store the buffer descriptors at the end of the first muram chunk.
0269      * For SMC ports on CPM2-based platforms, relocate the parameter RAM
0270      * just before the buffer descriptors.
0271      */
0272
0273     cbd_offset = muram_offset + muram_size - 2 * sizeof(struct cpm_bd);
0274
0275     if (is_cpm2 && is_smc) {
0276         u16 *smc_base = (u16 *)param;
0277         u16 pram_offset;
0278
0279         pram_offset = cbd_offset - 64;
0280         pram_offset = _ALIGN_DOWN(pram_offset, 64);
0281
0282         disable_port();
0283         out_be16(smc_base, pram_offset);
0284         param = muram_addr - muram_offset + pram_offset;
0285     }
0286
0287     cbd_addr = muram_addr - muram_offset + cbd_offset;
0288
0289     scdp->open = cpm_serial_open;
0290     scdp->putc = cpm_serial_putc;
0291     scdp->getc = cpm_serial_getc;
0292     scdp->tstc = cpm_serial_tstc;
0293
0294     return 0;
0295 }