diff options
Diffstat (limited to 'drivers/spi/tegra_spi.c')
| -rw-r--r-- | drivers/spi/tegra_spi.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/spi/tegra_spi.c b/drivers/spi/tegra_spi.c new file mode 100644 index 0000000..4a3e799 --- /dev/null +++ b/drivers/spi/tegra_spi.c @@ -0,0 +1,290 @@ +/* + * Copyright (c) 2010-2012 NVIDIA Corporation + * With help from the mpc8xxx SPI driver + * With more help from omap3_spi SPI driver + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +#include <common.h> + +#include <malloc.h> +#include <spi.h> +#include <asm/io.h> +#include <asm/gpio.h> +#include <asm/arch/clk_rst.h> +#include <asm/arch/clock.h> +#include <asm/arch/pinmux.h> +#include <asm/arch/uart-spi-switch.h> +#include <asm/arch/tegra_spi.h> + +#if defined(CONFIG_SPI_CORRUPTS_UART) + #define corrupt_delay() udelay(CONFIG_SPI_CORRUPTS_UART_DLY); +#else + #define corrupt_delay() +#endif + +struct tegra_spi_slave { + struct spi_slave slave; + struct spi_tegra *regs; + unsigned int freq; + unsigned int mode; +}; + +static inline struct tegra_spi_slave *to_tegra_spi(struct spi_slave *slave) +{ + return container_of(slave, struct tegra_spi_slave, slave); +} + +int spi_cs_is_valid(unsigned int bus, unsigned int cs) +{ + /* Tegra2 SPI-Flash - only 1 device ('bus/cs') */ + if (bus != 0 || cs != 0) + return 0; + else + return 1; +} + +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, + unsigned int max_hz, unsigned int mode) +{ + struct tegra_spi_slave *spi; + + if (!spi_cs_is_valid(bus, cs)) { + printf("SPI error: unsupported bus %d / chip select %d\n", + bus, cs); + return NULL; + } + + if (max_hz > TEGRA2_SPI_MAX_FREQ) { + printf("SPI error: unsupported frequency %d Hz. Max frequency" + " is %d Hz\n", max_hz, TEGRA2_SPI_MAX_FREQ); + return NULL; + } + + spi = malloc(sizeof(struct tegra_spi_slave)); + if (!spi) { + printf("SPI error: malloc of SPI structure failed\n"); + return NULL; + } + spi->slave.bus = bus; + spi->slave.cs = cs; + spi->freq = max_hz; + spi->regs = (struct spi_tegra *)TEGRA2_SPI_BASE; + spi->mode = mode; + + return &spi->slave; +} + +void spi_free_slave(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + + free(spi); +} + +void spi_init(void) +{ + /* do nothing */ +} + +int spi_claim_bus(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + struct spi_tegra *regs = spi->regs; + u32 reg; + + /* Change SPI clock to correct frequency, PLLP_OUT0 source */ + clock_start_periph_pll(PERIPH_ID_SPI1, CLOCK_ID_PERIPH, spi->freq); + + /* Clear stale status here */ + reg = SPI_STAT_RDY | SPI_STAT_RXF_FLUSH | SPI_STAT_TXF_FLUSH | \ + SPI_STAT_RXF_UNR | SPI_STAT_TXF_OVF; + writel(reg, ®s->status); + debug("spi_init: STATUS = %08x\n", readl(®s->status)); + + /* + * Use sw-controlled CS, so we can clock in data after ReadID, etc. + */ + reg = (spi->mode & 1) << SPI_CMD_ACTIVE_SDA_SHIFT; + if (spi->mode & 2) + reg |= 1 << SPI_CMD_ACTIVE_SCLK_SHIFT; + clrsetbits_le32(®s->command, SPI_CMD_ACTIVE_SCLK_MASK | + SPI_CMD_ACTIVE_SDA_MASK, SPI_CMD_CS_SOFT | reg); + debug("spi_init: COMMAND = %08x\n", readl(®s->command)); + + /* + * SPI pins on Tegra2 are muxed - change pinmux later due to UART + * issue. + */ + pinmux_set_func(PINGRP_GMD, PMUX_FUNC_SFLASH); + pinmux_tristate_disable(PINGRP_LSPI); + +#ifndef CONFIG_SPI_UART_SWITCH + /* + * NOTE: + * Only set PinMux bits 3:2 to SPI here on boards that don't have the + * SPI UART switch or subsequent UART data won't go out! See + * spi_uart_switch(). + */ + /* TODO: pinmux_set_func(PINGRP_GMC, PMUX_FUNC_SFLASH); */ +#endif + return 0; +} + +void spi_release_bus(struct spi_slave *slave) +{ + /* + * We can't release UART_DISABLE and set pinmux to UART4 here since + * some code (e,g, spi_flash_probe) uses printf() while the SPI + * bus is held. That is arguably bad, but it has the advantage of + * already being in the source tree. + */ +} + +void spi_cs_activate(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + + pinmux_select_spi(); + + /* CS is negated on Tegra, so drive a 1 to get a 0 */ + setbits_le32(&spi->regs->command, SPI_CMD_CS_VAL); + + corrupt_delay(); /* Let UART settle */ +} + +void spi_cs_deactivate(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + + pinmux_select_uart(); + + /* CS is negated on Tegra, so drive a 0 to get a 1 */ + clrbits_le32(&spi->regs->command, SPI_CMD_CS_VAL); + + corrupt_delay(); /* Let SPI settle */ +} + +int spi_xfer(struct spi_slave *slave, unsigned int bitlen, + const void *data_out, void *data_in, unsigned long flags) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + struct spi_tegra *regs = spi->regs; + u32 reg, tmpdout, tmpdin = 0; + const u8 *dout = data_out; + u8 *din = data_in; + int num_bytes; + int ret; + + debug("spi_xfer: slave %u:%u dout %08X din %08X bitlen %u\n", + slave->bus, slave->cs, *(u8 *)dout, *(u8 *)din, bitlen); + if (bitlen % 8) + return -1; + num_bytes = bitlen / 8; + + ret = 0; + + reg = readl(®s->status); + writel(reg, ®s->status); /* Clear all SPI events via R/W */ + debug("spi_xfer entry: STATUS = %08x\n", reg); + + reg = readl(®s->command); + reg |= SPI_CMD_TXEN | SPI_CMD_RXEN; + writel(reg, ®s->command); + debug("spi_xfer: COMMAND = %08x\n", readl(®s->command)); + + if (flags & SPI_XFER_BEGIN) + spi_cs_activate(slave); + + /* handle data in 32-bit chunks */ + while (num_bytes > 0) { + int bytes; + int is_read = 0; + int tm, i; + + tmpdout = 0; + bytes = (num_bytes > 4) ? 4 : num_bytes; + + if (dout != NULL) { + for (i = 0; i < bytes; ++i) + tmpdout = (tmpdout << 8) | dout[i]; + } + + num_bytes -= bytes; + if (dout) + dout += bytes; + + clrsetbits_le32(®s->command, SPI_CMD_BIT_LENGTH_MASK, + bytes * 8 - 1); + writel(tmpdout, ®s->tx_fifo); + setbits_le32(®s->command, SPI_CMD_GO); + + /* + * Wait for SPI transmit FIFO to empty, or to time out. + * The RX FIFO status will be read and cleared last + */ + for (tm = 0, is_read = 0; tm < SPI_TIMEOUT; ++tm) { + u32 status; + + status = readl(®s->status); + + /* We can exit when we've had both RX and TX activity */ + if (is_read && (status & SPI_STAT_TXF_EMPTY)) + break; + + if ((status & (SPI_STAT_BSY | SPI_STAT_RDY)) != + SPI_STAT_RDY) + tm++; + + else if (!(status & SPI_STAT_RXF_EMPTY)) { + tmpdin = readl(®s->rx_fifo); + is_read = 1; + + /* swap bytes read in */ + if (din != NULL) { + for (i = bytes - 1; i >= 0; --i) { + din[i] = tmpdin & 0xff; + tmpdin >>= 8; + } + din += bytes; + } + } + } + + if (tm >= SPI_TIMEOUT) + ret = tm; + + /* clear ACK RDY, etc. bits */ + writel(readl(®s->status), ®s->status); + } + + if (flags & SPI_XFER_END) + spi_cs_deactivate(slave); + + debug("spi_xfer: transfer ended. Value=%08x, status = %08x\n", + tmpdin, readl(®s->status)); + + if (ret) { + printf("spi_xfer: timeout during SPI transfer, tm %d\n", ret); + return -1; + } + + return 0; +} |