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path: root/drivers/spi/spi-cavium.c
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Diffstat (limited to 'drivers/spi/spi-cavium.c')
-rw-r--r--drivers/spi/spi-cavium.c151
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 000000000..5aaf21582
--- /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;
+}