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         u32 kwspi_mpp_config[] = { 0, 0 };
  45
  46         if (!spi_cs_is_valid(bus, cs))
  47                 return NULL;
  48
  49         slave = malloc(sizeof(struct spi_slave));
  50         if (!slave)
  51                 return NULL;
  52
  53         slave->bus = bus;
  54         slave->cs = cs;
  55
  56         writel(~KWSPI_CSN_ACT | KWSPI_SMEMRDY, &spireg->ctrl);
  57
  58         /* calculate spi clock prescaller using max_hz */
  59         data = ((CONFIG_SYS_TCLK / 2) / max_hz) & KWSPI_CLKPRESCL_MASK;
  60         data |= 0x10;
  61
  62         /* program spi clock prescaller using max_hz */
  63         writel(KWSPI_ADRLEN_3BYTE | data, &spireg->cfg);
  64         debug("data = 0x%08x \n", data);
  65
  66         writel(KWSPI_SMEMRDIRQ, &spireg->irq_cause);
  67         writel(KWSPI_IRQMASK, &spireg->irq_mask);
  68
  69         /* program mpp registers to select  SPI_CSn */
  70         if (cs) {
  71                 kwspi_mpp_config[0] = MPP7_SPI_SCn;
  72         } else {
  73                 kwspi_mpp_config[0] = MPP0_SPI_SCn;
  74         }
  75         kirkwood_mpp_conf(kwspi_mpp_config, cs_spi_mpp_back);
  76
  77         return slave;
  78 }
  79
  80 void spi_free_slave(struct spi_slave *slave)
  81 {
  82         kirkwood_mpp_conf(cs_spi_mpp_back, NULL);
  83         free(slave);
  84 }
  85
  86 #if defined(CONFIG_SYS_KW_SPI_MPP)
  87 u32 spi_mpp_backup[4];
  88 #endif
  89
  90 __attribute__((weak)) int board_spi_claim_bus(struct spi_slave *slave)
  91 {
  92         return 0;
  93 }
  94
  95 int spi_claim_bus(struct spi_slave *slave)
  96 {
  97 #if defined(CONFIG_SYS_KW_SPI_MPP)
  98         u32 config;
  99         u32 spi_mpp_config[4];
 100
 101         config = CONFIG_SYS_KW_SPI_MPP;
 102
 103         if (config & MOSI_MPP6)
 104                 spi_mpp_config[0] = MPP6_SPI_MOSI;
 105         else
 106                 spi_mpp_config[0] = MPP1_SPI_MOSI;
 107
 108         if (config & SCK_MPP10)
 109                 spi_mpp_config[1] = MPP10_SPI_SCK;
 110         else
 111                 spi_mpp_config[1] = MPP2_SPI_SCK;
 112
 113         if (config & MISO_MPP11)
 114                 spi_mpp_config[2] = MPP11_SPI_MISO;
 115         else
 116                 spi_mpp_config[2] = MPP3_SPI_MISO;
 117
 118         spi_mpp_config[3] = 0;
 119         spi_mpp_backup[3] = 0;
 120
 121         /* set new spi mpp and save current mpp config */
 122         kirkwood_mpp_conf(spi_mpp_config, spi_mpp_backup);
 123
 124 #endif
 125
 126         return board_spi_claim_bus(slave);
 127 }
 128
 129 __attribute__((weak)) void board_spi_release_bus(struct spi_slave *slave)
 130 {
 131 }
 132
 133 void spi_release_bus(struct spi_slave *slave)
 134 {
 135 #if defined(CONFIG_SYS_KW_SPI_MPP)
 136         kirkwood_mpp_conf(spi_mpp_backup, NULL);
 137 #endif
 138
 139         board_spi_release_bus(slave);
 140 }
 141
 142 #ifndef CONFIG_SPI_CS_IS_VALID
 143 /*
 144  * you can define this function board specific
 145  * define above CONFIG in board specific config file and
 146  * provide the function in board specific src file
 147  */
 148 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
 149 {
 150         return (bus == 0 && (cs == 0 || cs == 1));
 151 }
 152 #endif
 153
 154 void spi_init(void)
 155 {
 156 }
 157
 158 void spi_cs_activate(struct spi_slave *slave)
 159 {
 160         writel(readl(&spireg->ctrl) | KWSPI_IRQUNMASK, &spireg->ctrl);
 161 }
 162
 163 void spi_cs_deactivate(struct spi_slave *slave)
 164 {
 165         writel(readl(&spireg->ctrl) & KWSPI_IRQMASK, &spireg->ctrl);
 166 }
 167
 168 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 169              void *din, unsigned long flags)
 170 {
 171         unsigned int tmpdout, tmpdin;
 172         int tm, isread = 0;
 173
 174         debug("spi_xfer: slave %u:%u dout %p din %p bitlen %u\n",
 175               slave->bus, slave->cs, dout, din, bitlen);
 176
 177         if (flags & SPI_XFER_BEGIN)
 178                 spi_cs_activate(slave);
 179
 180         /*
 181          * handle data in 8-bit chunks
 182          * TBD: 2byte xfer mode to be enabled
 183          */
 184         writel(((readl(&spireg->cfg) & ~KWSPI_XFERLEN_MASK) |
 185                 KWSPI_XFERLEN_1BYTE), &spireg->cfg);
 186
 187         while (bitlen > 4) {
 188                 debug("loopstart bitlen %d\n", bitlen);
 189                 tmpdout = 0;
 190
 191                 /* Shift data so it's msb-justified */
 192                 if (dout)
 193                         tmpdout = *(u32 *) dout & 0x0ff;
 194
 195                 writel(~KWSPI_SMEMRDIRQ, &spireg->irq_cause);
 196                 writel(tmpdout, &spireg->dout); /* Write the data out */
 197                 debug("*** spi_xfer: ... %08x written, bitlen %d\n",
 198                       tmpdout, bitlen);
 199
 200                 /*
 201                  * Wait for SPI transmit to get out
 202                  * or time out (1 second = 1000 ms)
 203                  * The NE event must be read and cleared first
 204                  */
 205                 for (tm = 0, isread = 0; tm < KWSPI_TIMEOUT; ++tm) {
 206                         if (readl(&spireg->irq_cause) & KWSPI_SMEMRDIRQ) {
 207                                 isread = 1;
 208                                 tmpdin = readl(&spireg->din);
 209                                 debug
 210                                         ("spi_xfer: din %p..%08x read\n",
 211                                         din, tmpdin);
 212
 213                                 if (din) {
 214                                         *((u8 *) din) = (u8) tmpdin;
 215                                         din += 1;
 216                                 }
 217                                 if (dout)
 218                                         dout += 1;
 219                                 bitlen -= 8;
 220                         }
 221                         if (isread)
 222                                 break;
 223                 }
 224                 if (tm >= KWSPI_TIMEOUT)
 225                         printf("*** spi_xfer: Time out during SPI transfer\n");
 226
 227                 debug("loopend bitlen %d\n", bitlen);
 228         }
 229
 230         if (flags & SPI_XFER_END)
 231                 spi_cs_deactivate(slave);
 232
 233         return 0;
 234 }