diff options
Diffstat (limited to 'drivers/spi/spi-cavium.c')
| -rw-r--r-- | drivers/spi/spi-cavium.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/spi/spi-cavium.c b/drivers/spi/spi-cavium.c new file mode 100644 index 000000000000..5aaf21582cb5 --- /dev/null +++ b/drivers/spi/spi-cavium.c @@ -0,0 +1,151 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2011, 2012 Cavium, Inc. + */ + +#include <linux/spi/spi.h> +#include <linux/module.h> +#include <linux/delay.h> +#include <linux/io.h> + +#include "spi-cavium.h" + +static void octeon_spi_wait_ready(struct octeon_spi *p) +{ + union cvmx_mpi_sts mpi_sts; + unsigned int loops = 0; + + do { + if (loops++) + __delay(500); + mpi_sts.u64 = readq(p->register_base + OCTEON_SPI_STS(p)); + } while (mpi_sts.s.busy); +} + +static int octeon_spi_do_transfer(struct octeon_spi *p, + struct spi_message *msg, + struct spi_transfer *xfer, + bool last_xfer) +{ + struct spi_device *spi = msg->spi; + union cvmx_mpi_cfg mpi_cfg; + union cvmx_mpi_tx mpi_tx; + unsigned int clkdiv; + int mode; + bool cpha, cpol; + const u8 *tx_buf; + u8 *rx_buf; + int len; + int i; + + mode = spi->mode; + cpha = mode & SPI_CPHA; + cpol = mode & SPI_CPOL; + + clkdiv = p->sys_freq / (2 * xfer->speed_hz); + + mpi_cfg.u64 = 0; + + mpi_cfg.s.clkdiv = clkdiv; + mpi_cfg.s.cshi = (mode & SPI_CS_HIGH) ? 1 : 0; + mpi_cfg.s.lsbfirst = (mode & SPI_LSB_FIRST) ? 1 : 0; + mpi_cfg.s.wireor = (mode & SPI_3WIRE) ? 1 : 0; + mpi_cfg.s.idlelo = cpha != cpol; + mpi_cfg.s.cslate = cpha ? 1 : 0; + mpi_cfg.s.enable = 1; + + if (spi->chip_select < 4) + p->cs_enax |= 1ull << (12 + spi->chip_select); + mpi_cfg.u64 |= p->cs_enax; + + if (mpi_cfg.u64 != p->last_cfg) { + p->last_cfg = mpi_cfg.u64; + writeq(mpi_cfg.u64, p->register_base + OCTEON_SPI_CFG(p)); + } + tx_buf = xfer->tx_buf; + rx_buf = xfer->rx_buf; + len = xfer->len; + while (len > OCTEON_SPI_MAX_BYTES) { + for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) { + u8 d; + if (tx_buf) + d = *tx_buf++; + else + d = 0; + writeq(d, p->register_base + OCTEON_SPI_DAT0(p) + (8 * i)); + } + mpi_tx.u64 = 0; + mpi_tx.s.csid = spi->chip_select; + mpi_tx.s.leavecs = 1; + mpi_tx.s.txnum = tx_buf ? OCTEON_SPI_MAX_BYTES : 0; + mpi_tx.s.totnum = OCTEON_SPI_MAX_BYTES; + writeq(mpi_tx.u64, p->register_base + OCTEON_SPI_TX(p)); + + octeon_spi_wait_ready(p); + if (rx_buf) + for (i = 0; i < OCTEON_SPI_MAX_BYTES; i++) { + u64 v = readq(p->register_base + OCTEON_SPI_DAT0(p) + (8 * i)); + *rx_buf++ = (u8)v; + } + len -= OCTEON_SPI_MAX_BYTES; + } + + for (i = 0; i < len; i++) { + u8 d; + if (tx_buf) + d = *tx_buf++; + else + d = 0; + writeq(d, p->register_base + OCTEON_SPI_DAT0(p) + (8 * i)); + } + + mpi_tx.u64 = 0; + mpi_tx.s.csid = spi->chip_select; + if (last_xfer) + mpi_tx.s.leavecs = xfer->cs_change; + else + mpi_tx.s.leavecs = !xfer->cs_change; + mpi_tx.s.txnum = tx_buf ? len : 0; + mpi_tx.s.totnum = len; + writeq(mpi_tx.u64, p->register_base + OCTEON_SPI_TX(p)); + + octeon_spi_wait_ready(p); + if (rx_buf) + for (i = 0; i < len; i++) { + u64 v = readq(p->register_base + OCTEON_SPI_DAT0(p) + (8 * i)); + *rx_buf++ = (u8)v; + } + + if (xfer->delay_usecs) + udelay(xfer->delay_usecs); + + return xfer->len; +} + +int octeon_spi_transfer_one_message(struct spi_master *master, + struct spi_message *msg) +{ + struct octeon_spi *p = spi_master_get_devdata(master); + unsigned int total_len = 0; + int status = 0; + struct spi_transfer *xfer; + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + bool last_xfer = list_is_last(&xfer->transfer_list, + &msg->transfers); + int r = octeon_spi_do_transfer(p, msg, xfer, last_xfer); + if (r < 0) { + status = r; + goto err; + } + total_len += r; + } +err: + msg->status = status; + msg->actual_length = total_len; + spi_finalize_current_message(master); + return status; +} |