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 int spi_claim_bus(struct spi_slave *slave)
  87 {
  88         return 0;
  89 }
  90
  91 void spi_release_bus(struct spi_slave *slave)
  92 {
  93 }
  94
  95 #ifndef CONFIG_SPI_CS_IS_VALID
  96 /*
  97  * you can define this function board specific
  98  * define above CONFIG in board specific config file and
  99  * provide the function in board specific src file
 100  */
 101 int spi_cs_is_valid(unsigned int bus, unsigned int cs)
 102 {
 103         return (bus == 0 && (cs == 0 || cs == 1));
 104 }
 105 #endif
 106
 107 void spi_init(void)
 108 {
 109 }
 110
 111 void spi_cs_activate(struct spi_slave *slave)
 112 {
 113         writel(readl(&spireg->ctrl) | KWSPI_IRQUNMASK, &spireg->ctrl);
 114 }
 115
 116 void spi_cs_deactivate(struct spi_slave *slave)
 117 {
 118         writel(readl(&spireg->ctrl) & KWSPI_IRQMASK, &spireg->ctrl);
 119 }
 120
 121 int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
 122              void *din, unsigned long flags)
 123 {
 124         unsigned int tmpdout, tmpdin;
 125         int tm, isread = 0;
 126
 127         debug("spi_xfer: slave %u:%u dout %p din %p bitlen %u\n",
 128               slave->bus, slave->cs, dout, din, bitlen);
 129
 130         if (flags & SPI_XFER_BEGIN)
 131                 spi_cs_activate(slave);
 132
 133         /*
 134          * handle data in 8-bit chunks
 135          * TBD: 2byte xfer mode to be enabled
 136          */
 137         writel(((readl(&spireg->cfg) & ~KWSPI_XFERLEN_MASK) |
 138                 KWSPI_XFERLEN_1BYTE), &spireg->cfg);
 139
 140         while (bitlen > 4) {
 141                 debug("loopstart bitlen %d\n", bitlen);
 142                 tmpdout = 0;
 143
 144                 /* Shift data so it's msb-justified */
 145                 if (dout)
 146                         tmpdout = *(u32 *) dout & 0x0ff;
 147
 148                 writel(~KWSPI_SMEMRDIRQ, &spireg->irq_cause);
 149                 writel(tmpdout, &spireg->dout); /* Write the data out */
 150                 debug("*** spi_xfer: ... %08x written, bitlen %d\n",
 151                       tmpdout, bitlen);
 152
 153                 /*
 154                  * Wait for SPI transmit to get out
 155                  * or time out (1 second = 1000 ms)
 156                  * The NE event must be read and cleared first
 157                  */
 158                 for (tm = 0, isread = 0; tm < KWSPI_TIMEOUT; ++tm) {
 159                         if (readl(&spireg->irq_cause) & KWSPI_SMEMRDIRQ) {
 160                                 isread = 1;
 161                                 tmpdin = readl(&spireg->din);
 162                                 debug
 163                                         ("spi_xfer: din %p..%08x read\n",
 164                                         din, tmpdin);
 165
 166                                 if (din) {
 167                                         *((u8 *) din) = (u8) tmpdin;
 168                                         din += 1;
 169                                 }
 170                                 if (dout)
 171                                         dout += 1;
 172                                 bitlen -= 8;
 173                         }
 174                         if (isread)
 175                                 break;
 176                 }
 177                 if (tm >= KWSPI_TIMEOUT)
 178                         printf("*** spi_xfer: Time out during SPI transfer\n");
 179
 180                 debug("loopend bitlen %d\n", bitlen);
 181         }
 182
 183         if (flags & SPI_XFER_END)
 184                 spi_cs_deactivate(slave);
 185
 186         return 0;
 187 }