diff options
Diffstat (limited to 'drivers/spi/tegra20_slink.c')
| -rw-r--r-- | drivers/spi/tegra20_slink.c | 359 |
1 files changed, 359 insertions, 0 deletions
diff --git a/drivers/spi/tegra20_slink.c b/drivers/spi/tegra20_slink.c new file mode 100644 index 0000000000..664de6e916 --- /dev/null +++ b/drivers/spi/tegra20_slink.c @@ -0,0 +1,359 @@ +/* + * NVIDIA Tegra SPI-SLINK controller + * + * Copyright (c) 2010-2013 NVIDIA Corporation + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * 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 <asm/io.h> +#include <asm/gpio.h> +#include <asm/arch/clock.h> +#include <asm/arch-tegra/clk_rst.h> +#include <asm/arch-tegra20/tegra20_slink.h> +#include <spi.h> +#include <fdtdec.h> + +DECLARE_GLOBAL_DATA_PTR; + +/* COMMAND */ +#define SLINK_CMD_ENB (1 << 31) +#define SLINK_CMD_GO (1 << 30) +#define SLINK_CMD_M_S (1 << 28) +#define SLINK_CMD_CK_SDA (1 << 21) +#define SLINK_CMD_CS_POL (1 << 13) +#define SLINK_CMD_CS_VAL (1 << 12) +#define SLINK_CMD_CS_SOFT (1 << 11) +#define SLINK_CMD_BIT_LENGTH (1 << 4) +#define SLINK_CMD_BIT_LENGTH_MASK 0x0000001F +/* COMMAND2 */ +#define SLINK_CMD2_TXEN (1 << 30) +#define SLINK_CMD2_RXEN (1 << 31) +#define SLINK_CMD2_SS_EN (1 << 18) +#define SLINK_CMD2_SS_EN_SHIFT 18 +#define SLINK_CMD2_SS_EN_MASK 0x000C0000 +#define SLINK_CMD2_CS_ACTIVE_BETWEEN (1 << 17) +/* STATUS */ +#define SLINK_STAT_BSY (1 << 31) +#define SLINK_STAT_RDY (1 << 30) +#define SLINK_STAT_ERR (1 << 29) +#define SLINK_STAT_RXF_FLUSH (1 << 27) +#define SLINK_STAT_TXF_FLUSH (1 << 26) +#define SLINK_STAT_RXF_OVF (1 << 25) +#define SLINK_STAT_TXF_UNR (1 << 24) +#define SLINK_STAT_RXF_EMPTY (1 << 23) +#define SLINK_STAT_RXF_FULL (1 << 22) +#define SLINK_STAT_TXF_EMPTY (1 << 21) +#define SLINK_STAT_TXF_FULL (1 << 20) +#define SLINK_STAT_TXF_OVF (1 << 19) +#define SLINK_STAT_RXF_UNR (1 << 18) +#define SLINK_STAT_CUR_BLKCNT (1 << 15) +/* STATUS2 */ +#define SLINK_STAT2_RXF_FULL_CNT (1 << 16) +#define SLINK_STAT2_TXF_FULL_CNT (1 << 0) + +#define SPI_TIMEOUT 1000 +#define TEGRA_SPI_MAX_FREQ 52000000 + +struct spi_regs { + u32 command; /* SLINK_COMMAND_0 register */ + u32 command2; /* SLINK_COMMAND2_0 reg */ + u32 status; /* SLINK_STATUS_0 register */ + u32 reserved; /* Reserved offset 0C */ + u32 mas_data; /* SLINK_MAS_DATA_0 reg */ + u32 slav_data; /* SLINK_SLAVE_DATA_0 reg */ + u32 dma_ctl; /* SLINK_DMA_CTL_0 register */ + u32 status2; /* SLINK_STATUS2_0 reg */ + u32 rsvd[56]; /* 0x20 to 0xFF reserved */ + u32 tx_fifo; /* SLINK_TX_FIFO_0 reg off 100h */ + u32 rsvd2[31]; /* 0x104 to 0x17F reserved */ + u32 rx_fifo; /* SLINK_RX_FIFO_0 reg off 180h */ +}; + +struct tegra_spi_ctrl { + struct spi_regs *regs; + unsigned int freq; + unsigned int mode; + int periph_id; + int valid; +}; + +struct tegra_spi_slave { + struct spi_slave slave; + struct tegra_spi_ctrl *ctrl; +}; + +static struct tegra_spi_ctrl spi_ctrls[CONFIG_TEGRA_SLINK_CTRLS]; + +static inline struct tegra_spi_slave *to_tegra_spi(struct spi_slave *slave) +{ + return container_of(slave, struct tegra_spi_slave, slave); +} + +int tegra30_spi_cs_is_valid(unsigned int bus, unsigned int cs) +{ + if (bus >= CONFIG_TEGRA_SLINK_CTRLS || cs > 3 || !spi_ctrls[bus].valid) + return 0; + else + return 1; +} + +struct spi_slave *tegra30_spi_setup_slave(unsigned int bus, unsigned int cs, + unsigned int max_hz, unsigned int mode) +{ + struct tegra_spi_slave *spi; + + debug("%s: bus: %u, cs: %u, max_hz: %u, mode: %u\n", __func__, + bus, cs, max_hz, mode); + + if (!spi_cs_is_valid(bus, cs)) { + printf("SPI error: unsupported bus %d / chip select %d\n", + bus, cs); + return NULL; + } + + if (max_hz > TEGRA_SPI_MAX_FREQ) { + printf("SPI error: unsupported frequency %d Hz. Max frequency" + " is %d Hz\n", max_hz, TEGRA_SPI_MAX_FREQ); + return NULL; + } + + spi = spi_alloc_slave(struct tegra_spi_slave, bus, cs); + if (!spi) { + printf("SPI error: malloc of SPI structure failed\n"); + return NULL; + } + spi->ctrl = &spi_ctrls[bus]; + if (!spi->ctrl) { + printf("SPI error: could not find controller for bus %d\n", + bus); + return NULL; + } + + if (max_hz < spi->ctrl->freq) { + debug("%s: limiting frequency from %u to %u\n", __func__, + spi->ctrl->freq, max_hz); + spi->ctrl->freq = max_hz; + } + spi->ctrl->mode = mode; + + return &spi->slave; +} + +void tegra30_spi_free_slave(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + + free(spi); +} + +int tegra30_spi_init(int *node_list, int count) +{ + struct tegra_spi_ctrl *ctrl; + int i; + int node = 0; + int found = 0; + + for (i = 0; i < count; i++) { + ctrl = &spi_ctrls[i]; + node = node_list[i]; + + ctrl->regs = (struct spi_regs *)fdtdec_get_addr(gd->fdt_blob, + node, "reg"); + if ((fdt_addr_t)ctrl->regs == FDT_ADDR_T_NONE) { + debug("%s: no slink register found\n", __func__); + continue; + } + ctrl->freq = fdtdec_get_int(gd->fdt_blob, node, + "spi-max-frequency", 0); + if (!ctrl->freq) { + debug("%s: no slink max frequency found\n", __func__); + continue; + } + + ctrl->periph_id = clock_decode_periph_id(gd->fdt_blob, node); + if (ctrl->periph_id == PERIPH_ID_NONE) { + debug("%s: could not decode periph id\n", __func__); + continue; + } + ctrl->valid = 1; + found = 1; + + debug("%s: found controller at %p, freq = %u, periph_id = %d\n", + __func__, ctrl->regs, ctrl->freq, ctrl->periph_id); + } + return !found; +} + +int tegra30_spi_claim_bus(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + struct spi_regs *regs = spi->ctrl->regs; + u32 reg; + + /* Change SPI clock to correct frequency, PLLP_OUT0 source */ + clock_start_periph_pll(spi->ctrl->periph_id, CLOCK_ID_PERIPH, + spi->ctrl->freq); + + /* Clear stale status here */ + reg = SLINK_STAT_RDY | SLINK_STAT_RXF_FLUSH | SLINK_STAT_TXF_FLUSH | \ + SLINK_STAT_RXF_UNR | SLINK_STAT_TXF_OVF; + writel(reg, ®s->status); + debug("%s: STATUS = %08x\n", __func__, readl(®s->status)); + + /* Set master mode and sw controlled CS */ + reg = readl(®s->command); + reg |= SLINK_CMD_M_S | SLINK_CMD_CS_SOFT; + writel(reg, ®s->command); + debug("%s: COMMAND = %08x\n", __func__, readl(®s->command)); + + return 0; +} + +void tegra30_spi_cs_activate(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + struct spi_regs *regs = spi->ctrl->regs; + + /* CS is negated on Tegra, so drive a 1 to get a 0 */ + setbits_le32(®s->command, SLINK_CMD_CS_VAL); +} + +void tegra30_spi_cs_deactivate(struct spi_slave *slave) +{ + struct tegra_spi_slave *spi = to_tegra_spi(slave); + struct spi_regs *regs = spi->ctrl->regs; + + /* CS is negated on Tegra, so drive a 0 to get a 1 */ + clrbits_le32(®s->command, SLINK_CMD_CS_VAL); +} + +int tegra30_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_regs *regs = spi->ctrl->regs; + u32 reg, tmpdout, tmpdin = 0; + const u8 *dout = data_out; + u8 *din = data_in; + int num_bytes; + int ret; + + debug("%s: slave %u:%u dout %p din %p bitlen %u\n", + __func__, slave->bus, slave->cs, dout, 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("%s entry: STATUS = %08x\n", __func__, reg); + + reg = readl(®s->status2); + writel(reg, ®s->status2); /* Clear all STATUS2 events via R/W */ + debug("%s entry: STATUS2 = %08x\n", __func__, reg); + + debug("%s entry: COMMAND = %08x\n", __func__, readl(®s->command)); + + clrsetbits_le32(®s->command2, SLINK_CMD2_SS_EN_MASK, + SLINK_CMD2_TXEN | SLINK_CMD2_RXEN | + (slave->cs << SLINK_CMD2_SS_EN_SHIFT)); + debug("%s entry: COMMAND2 = %08x\n", __func__, readl(®s->command2)); + + 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]; + dout += bytes; + } + + num_bytes -= bytes; + + clrsetbits_le32(®s->command, SLINK_CMD_BIT_LENGTH_MASK, + bytes * 8 - 1); + writel(tmpdout, ®s->tx_fifo); + setbits_le32(®s->command, SLINK_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 & SLINK_STAT_TXF_EMPTY)) + break; + + if ((status & (SLINK_STAT_BSY | SLINK_STAT_RDY)) != + SLINK_STAT_RDY) + tm++; + + else if (!(status & SLINK_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("%s: transfer ended. Value=%08x, status = %08x\n", + __func__, tmpdin, readl(®s->status)); + + if (ret) { + printf("%s: timeout during SPI transfer, tm %d\n", + __func__, ret); + return -1; + } + + return 0; +} |