drivers/spi/kirkwood_spi.c

   1 /*
   2  * (C) Copyright 2009
   3  * Marvell Semiconductor <www.marvell.com>
   4  * Written-by: Prafulla Wadaskar <prafulla@marvell.com>
   5  *
   6  * Derived from drivers/spi/mpc8xxx_spi.c
   7  *
   8  * See file CREDITS for list of people who contributed to this
   9  * project.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of
  14  * the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  24  * MA 02110-1301 USA
  25  */
  26
  27 #include <common.h>
  28 #include <malloc.h>
  29 #include <spi.h>
  30 #include <asm/io.h>
  31 #include <asm/arch/kirkwood.h>
  32 #include <asm/arch/spi.h>
  33 #include <asm/arch/mpp.h>
  34
  35 static struct kwspi_registers *spireg = (struct kwspi_registers *)KW_SPI_BASE;
  36
  37 u32 cs_spi_mpp_back[2];
  38
  39 struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
  40                                 unsigned int max_hz, unsigned int mode)
  41 {
  42         struct spi_slave *slave;
  43         u32 data;
  44         static const u32 kwspi_mpp_config[2][2] = {
  45                 { MPP0_SPI_SCn, 0 }, /* if cs == 0 */
  46                 { MPP7_SPI_SCn, 0 } /* if cs != 0 */
  47         };
  48
  49         if (!spi_cs_is_valid(bus, cs))
  50                 return NULL;
  51
  52         slave = malloc(sizeof(struct spi_slave));
  53         if (!slave)
  54                 return NULL;
  55
  56         slave->bus = bus;
  57         slave->cs = cs;
  58
  59         writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
  60
  61         /* calculate spi clock prescaller using max_hz */
  62         data = ((CONFIG_SYS_TCLK / 2) / max_hz) + 0x10;
  63         data = data < KWSPI_CLKPRESCL_MIN ? KWSPI_CLKPRESCL_MIN : data;
  64         data = data > KWSPI_CLKPRESCL_MASK ? KWSPI_CLKPRESCL_MASK : data;
  65
  66         /* program spi clock prescaller using max_hz */
  67         writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
  68         debug("data = 0x%08x \n", data);
  69
  70         writel(KWSPI_SMEMRDIRQ, &spireg->irq_cause);
  71         writel(KWSPI_IRQMASK, &spireg->irq_mask);
  72
  73         /* program mpp registers to select  SPI_CSn */
  74         kirkwood_mpp_conf(kwspi_mpp_config[cs ? 1 : 0], cs_spi_mpp_back);
  75
  76         return slave;
  77 }
  78
  79 void spi_free_slave(struct spi_slave *slave)
  80 {
  81         kirkwood_mpp_conf(cs_spi_mpp_back, NULL);
  82         free(slave);
  83 }
  84
  85 #if defined(CONFIG_SYS_KW_SPI_MPP)
  86 u32 spi_mpp_backup[4];
  87 #endif
  88
  89 __attribute__((weak)) int board_spi_claim_bus(struct spi_slave *slave)
  90 {
  91         return 0;
  92 }
  93
  94 int spi_claim_bus(struct spi_slave *slave)
  95 {
  96 #if defined(CONFIG_SYS_KW_SPI_MPP)
  97         u32 config;
  98         u32 spi_mpp_config[4];
  99
 100         config = CONFIG_SYS_KW_SPI_MPP;
 101
 102         if (config & MOSI_MPP6)
 103                 spi_mpp_config[0] = MPP6_SPI_MOSI;
 104         else
 105                 spi_mpp_config[0] = MPP1_SPI_MOSI;
 106
 107         if (config & SCK_MPP10)
 108                 spi_mpp_config[1] = MPP10_SPI_SCK;
 109         else
 110                 spi_mpp_config[1] = MPP2_SPI_SCK;
 111
 112         if (config & MISO_MPP11)
 113                 spi_mpp_config[2] = MPP11_SPI_MISO;
 114         else
 115                 spi_mpp_config[2] = MPP3_SPI_MISO;
 116
 117         spi_mpp_config[3] = 0;
 118         spi_mpp_backup[3] = 0;
 119
 120         /* set new spi mpp and save current mpp config */
 121         kirkwood_mpp_conf(spi_mpp_config, spi_mpp_backup);
 122
 123 #endif
 124
 125         return board_spi_claim_bus(slave);
 126 }
 127
 128 __attribute__((weak)) void board_spi_release_bus(struct spi_slave *slave)
 129 {
 130 }
 131
 132 void spi_release_bus(struct spi_slave *slave)
 133 {
 134 #if defined(CONFIG_SYS_KW_SPI_MPP)
 135         kirkwood_mpp_conf(spi_mpp_backup, NULL);
 136 #endif
 137
 138         board_spi_release_bus(slave);
 139 }
 140
 141 #ifndef CONFIG_SPI_CS_IS_VALID
 142 /*
 143  * you can define this function board specific
 144  * define above CONFIG in board specific config file and
 145  * provide the function in board specific src file
 146  */
 147 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
 148 {
 149         return (bus == 0 && (cs == 0 || cs == 1));
 150 }
 151 #endif
 152
 153 void spi_init(void)
 154 {
 155 }
 156
 157 void spi_cs_activate(struct spi_slave *slave)
 158 {
 159         writel(readl(&spireg->ctrl) | KWSPI_IRQUNMASK, &spireg->ctrl);
 160 }
 161
 162 void spi_cs_deactivate(struct spi_slave *slave)
 163 {
 164         writel(readl(&spireg->ctrl) & KWSPI_IRQMASK, &spireg->ctrl);
 165 }
 166
 167 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 168              void *din, unsigned long flags)
 169 {
 170         unsigned int tmpdout, tmpdin;
 171         int tm, isread = 0;
 172
 173         debug("spi_xfer: slave %u:%u dout %p din %p bitlen %u\n",
 174               slave->bus, slave->cs, dout, din, bitlen);
 175
 176         if (flags & SPI_XFER_BEGIN)
 177                 spi_cs_activate(slave);
 178
 179         /*
 180          * handle data in 8-bit chunks
 181          * TBD: 2byte xfer mode to be enabled
 182          */
 183         writel(((readl(&spireg->cfg) & ~KWSPI_XFERLEN_MASK) |
 184                 KWSPI_XFERLEN_1BYTE), &spireg->cfg);
 185
 186         while (bitlen > 4) {
 187                 debug("loopstart bitlen %d\n", bitlen);
 188                 tmpdout = 0;
 189
 190                 /* Shift data so it's msb-justified */
 191                 if (dout)
 192                         tmpdout = *(u32 *) dout & 0x0ff;
 193
 194                 writel(~KWSPI_SMEMRDIRQ, &spireg->irq_cause);
 195                 writel(tmpdout, &spireg->dout); /* Write the data out */
 196                 debug("*** spi_xfer: ... %08x written, bitlen %d\n",
 197                       tmpdout, bitlen);
 198
 199                 /*
 200                  * Wait for SPI transmit to get out
 201                  * or time out (1 second = 1000 ms)
 202                  * The NE event must be read and cleared first
 203                  */
 204                 for (tm = 0, isread = 0; tm < KWSPI_TIMEOUT; ++tm) {
 205                         if (readl(&spireg->irq_cause) & KWSPI_SMEMRDIRQ) {
 206                                 isread = 1;
 207                                 tmpdin = readl(&spireg->din);
 208                                 debug
 209                                         ("spi_xfer: din %p..%08x read\n",
 210                                         din, tmpdin);
 211
 212                                 if (din) {
 213                                         *((u8 *) din) = (u8) tmpdin;
 214                                         din += 1;
 215                                 }
 216                                 if (dout)
 217                                         dout += 1;
 218                                 bitlen -= 8;
 219                         }
 220                         if (isread)
 221                                 break;
 222                 }
 223                 if (tm >= KWSPI_TIMEOUT)
 224                         printf("*** spi_xfer: Time out during SPI transfer\n");
 225
 226                 debug("loopend bitlen %d\n", bitlen);
 227         }
 228
 229         if (flags & SPI_XFER_END)
 230                 spi_cs_deactivate(slave);
 231
 232         return 0;
 233 }