1 /* 2 * SH SPI driver 3 * 4 * Copyright (C) 2011 Renesas Solutions Corp. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; version 2 of the License. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write to the Free Software 17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 18 * 19 */ 20 21 #include <common.h> 22 #include <malloc.h> 23 #include <spi.h> 24 #include <asm/io.h> 25 #include "sh_spi.h" 26 27 static void sh_spi_write(unsigned long data, unsigned long *reg) 28 { 29 writel(data, reg); 30 } 31 32 static unsigned long sh_spi_read(unsigned long *reg) 33 { 34 return readl(reg); 35 } 36 37 static void sh_spi_set_bit(unsigned long val, unsigned long *reg) 38 { 39 unsigned long tmp; 40 41 tmp = sh_spi_read(reg); 42 tmp |= val; 43 sh_spi_write(tmp, reg); 44 } 45 46 static void sh_spi_clear_bit(unsigned long val, unsigned long *reg) 47 { 48 unsigned long tmp; 49 50 tmp = sh_spi_read(reg); 51 tmp &= ~val; 52 sh_spi_write(tmp, reg); 53 } 54 55 static void clear_fifo(struct sh_spi *ss) 56 { 57 sh_spi_set_bit(SH_SPI_RSTF, &ss->regs->cr2); 58 sh_spi_clear_bit(SH_SPI_RSTF, &ss->regs->cr2); 59 } 60 61 static int recvbuf_wait(struct sh_spi *ss) 62 { 63 while (sh_spi_read(&ss->regs->cr1) & SH_SPI_RBE) { 64 if (ctrlc()) 65 return 1; 66 udelay(10); 67 } 68 return 0; 69 } 70 71 static int write_fifo_empty_wait(struct sh_spi *ss) 72 { 73 while (!(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBE)) { 74 if (ctrlc()) 75 return 1; 76 udelay(10); 77 } 78 return 0; 79 } 80 81 void spi_init(void) 82 { 83 } 84 85 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, 86 unsigned int max_hz, unsigned int mode) 87 { 88 struct sh_spi *ss; 89 90 if (!spi_cs_is_valid(bus, cs)) 91 return NULL; 92 93 ss = malloc(sizeof(struct spi_slave)); 94 if (!ss) 95 return NULL; 96 97 ss->slave.bus = bus; 98 ss->slave.cs = cs; 99 ss->regs = (struct sh_spi_regs *)CONFIG_SH_SPI_BASE; 100 101 /* SPI sycle stop */ 102 sh_spi_write(0xfe, &ss->regs->cr1); 103 /* CR1 init */ 104 sh_spi_write(0x00, &ss->regs->cr1); 105 /* CR3 init */ 106 sh_spi_write(0x00, &ss->regs->cr3); 107 108 clear_fifo(ss); 109 110 /* 1/8 clock */ 111 sh_spi_write(sh_spi_read(&ss->regs->cr2) | 0x07, &ss->regs->cr2); 112 udelay(10); 113 114 return &ss->slave; 115 } 116 117 void spi_free_slave(struct spi_slave *slave) 118 { 119 struct sh_spi *spi = to_sh_spi(slave); 120 121 free(spi); 122 } 123 124 int spi_claim_bus(struct spi_slave *slave) 125 { 126 return 0; 127 } 128 129 void spi_release_bus(struct spi_slave *slave) 130 { 131 struct sh_spi *ss = to_sh_spi(slave); 132 133 sh_spi_write(sh_spi_read(&ss->regs->cr1) & 134 ~(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD), &ss->regs->cr1); 135 } 136 137 static int sh_spi_send(struct sh_spi *ss, const unsigned char *tx_data, 138 unsigned int len, unsigned long flags) 139 { 140 int i, cur_len, ret = 0; 141 int remain = (int)len; 142 unsigned long tmp; 143 144 if (len >= SH_SPI_FIFO_SIZE) 145 sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1); 146 147 while (remain > 0) { 148 cur_len = (remain < SH_SPI_FIFO_SIZE) ? 149 remain : SH_SPI_FIFO_SIZE; 150 for (i = 0; i < cur_len && 151 !(sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) && 152 !(sh_spi_read(&ss->regs->cr1) & SH_SPI_TBF); 153 i++) 154 sh_spi_write(tx_data[i], &ss->regs->tbr_rbr); 155 156 cur_len = i; 157 158 if (sh_spi_read(&ss->regs->cr4) & SH_SPI_WPABRT) { 159 /* Abort the transaction */ 160 flags |= SPI_XFER_END; 161 sh_spi_set_bit(SH_SPI_WPABRT, &ss->regs->cr4); 162 ret = 1; 163 break; 164 } 165 166 remain -= cur_len; 167 tx_data += cur_len; 168 169 if (remain > 0) 170 write_fifo_empty_wait(ss); 171 } 172 173 if (flags & SPI_XFER_END) { 174 tmp = sh_spi_read(&ss->regs->cr1); 175 tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB); 176 sh_spi_write(tmp, &ss->regs->cr1); 177 sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1); 178 udelay(100); 179 write_fifo_empty_wait(ss); 180 } 181 182 return ret; 183 } 184 185 static int sh_spi_receive(struct sh_spi *ss, unsigned char *rx_data, 186 unsigned int len, unsigned long flags) 187 { 188 int i; 189 unsigned long tmp; 190 191 if (len > SH_SPI_MAX_BYTE) 192 sh_spi_write(SH_SPI_MAX_BYTE, &ss->regs->cr3); 193 else 194 sh_spi_write(len, &ss->regs->cr3); 195 196 tmp = sh_spi_read(&ss->regs->cr1); 197 tmp = tmp & ~(SH_SPI_SSD | SH_SPI_SSDB); 198 sh_spi_write(tmp, &ss->regs->cr1); 199 sh_spi_set_bit(SH_SPI_SSA, &ss->regs->cr1); 200 201 for (i = 0; i < len; i++) { 202 if (recvbuf_wait(ss)) 203 return 0; 204 205 rx_data[i] = (unsigned char)sh_spi_read(&ss->regs->tbr_rbr); 206 } 207 sh_spi_write(0, &ss->regs->cr3); 208 209 return 0; 210 } 211 212 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, 213 void *din, unsigned long flags) 214 { 215 struct sh_spi *ss = to_sh_spi(slave); 216 const unsigned char *tx_data = dout; 217 unsigned char *rx_data = din; 218 unsigned int len = bitlen / 8; 219 int ret = 0; 220 221 if (flags & SPI_XFER_BEGIN) 222 sh_spi_write(sh_spi_read(&ss->regs->cr1) & ~SH_SPI_SSA, 223 &ss->regs->cr1); 224 225 if (tx_data) 226 ret = sh_spi_send(ss, tx_data, len, flags); 227 228 if (ret == 0 && rx_data) 229 ret = sh_spi_receive(ss, rx_data, len, flags); 230 231 if (flags & SPI_XFER_END) { 232 sh_spi_set_bit(SH_SPI_SSD, &ss->regs->cr1); 233 udelay(100); 234 235 sh_spi_clear_bit(SH_SPI_SSA | SH_SPI_SSDB | SH_SPI_SSD, 236 &ss->regs->cr1); 237 clear_fifo(ss); 238 } 239 240 return ret; 241 } 242 243 int spi_cs_is_valid(unsigned int bus, unsigned int cs) 244 { 245 /* This driver supports "bus = 0" and "cs = 0" only. */ 246 if (!bus && !cs) 247 return 1; 248 else 249 return 0; 250 } 251 252 void spi_cs_activate(struct spi_slave *slave) 253 { 254 255 } 256 257 void spi_cs_deactivate(struct spi_slave *slave) 258 { 259 260 } 261