* (C) Copyright 2012 SAMSUNG Electronics
* Padmavathi Venna <padma.v@samsung.com>
*
- * 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
+ * SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
struct exynos_spi *regs;
int inited; /* 1 if this bus is ready for use */
int node;
+ uint deactivate_delay_us; /* Delay to wait after deactivate */
};
/* A list of spi buses that we know about */
enum periph_id periph_id; /* Peripheral ID for this device */
unsigned int fifo_size;
int skip_preamble;
+ struct spi_bus *bus; /* Pointer to our SPI bus info */
+ ulong last_transaction_us; /* Time of last transaction end */
};
static struct spi_bus *spi_get_bus(unsigned dev_index)
}
bus = &spi_bus[busnum];
+ spi_slave->bus = bus;
spi_slave->regs = bus->regs;
spi_slave->mode = mode;
spi_slave->periph_id = bus->periph_id;
spi_slave->fifo_size = 256;
spi_slave->skip_preamble = 0;
+ spi_slave->last_transaction_us = timer_get_us();
spi_slave->freq = bus->frequency;
if (max_hz)
*
* @param regs SPI peripheral registers
* @param count Number of bytes to transfer
+ * @param step Number of bytes to transfer in each packet (1 or 4)
*/
-static void spi_request_bytes(struct exynos_spi *regs, int count)
+static void spi_request_bytes(struct exynos_spi *regs, int count, int step)
{
+ /* For word address we need to swap bytes */
+ if (step == 4) {
+ setbits_le32(®s->mode_cfg,
+ SPI_MODE_CH_WIDTH_WORD | SPI_MODE_BUS_WIDTH_WORD);
+ count /= 4;
+ setbits_le32(®s->swap_cfg, SPI_TX_SWAP_EN | SPI_RX_SWAP_EN |
+ SPI_TX_BYTE_SWAP | SPI_RX_BYTE_SWAP |
+ SPI_TX_HWORD_SWAP | SPI_RX_HWORD_SWAP);
+ } else {
+ /* Select byte access and clear the swap configuration */
+ clrbits_le32(®s->mode_cfg,
+ SPI_MODE_CH_WIDTH_WORD | SPI_MODE_BUS_WIDTH_WORD);
+ writel(0, ®s->swap_cfg);
+ }
+
assert(count && count < (1 << 16));
setbits_le32(®s->ch_cfg, SPI_CH_RST);
clrbits_le32(®s->ch_cfg, SPI_CH_RST);
+
writel(count | SPI_PACKET_CNT_EN, ®s->pkt_cnt);
}
int toread;
unsigned start = get_timer(0);
int stopping;
+ int step;
out_bytes = in_bytes = todo;
stopping = spi_slave->skip_preamble && (flags & SPI_XFER_END) &&
!(spi_slave->mode & SPI_SLAVE);
+ /*
+ * Try to transfer words if we can. This helps read performance at
+ * SPI clock speeds above about 20MHz.
+ */
+ step = 1;
+ if (!((todo | (uintptr_t)rxp | (uintptr_t)txp) & 3) &&
+ !spi_slave->skip_preamble)
+ step = 4;
+
/*
* If there's something to send, do a software reset and set a
* transaction size.
*/
- spi_request_bytes(regs, todo);
+ spi_request_bytes(regs, todo, step);
/*
* Bytes are transmitted/received in pairs. Wait to receive all the
/* Keep the fifos full/empty. */
spi_get_fifo_levels(regs, &rx_lvl, &tx_lvl);
- if (tx_lvl < spi_slave->fifo_size && out_bytes) {
- temp = txp ? *txp++ : 0xff;
+
+ /*
+ * Don't completely fill the txfifo, since we don't want our
+ * rxfifo to overflow, and it may already contain data.
+ */
+ while (tx_lvl < spi_slave->fifo_size/2 && out_bytes) {
+ if (!txp)
+ temp = -1;
+ else if (step == 4)
+ temp = *(uint32_t *)txp;
+ else
+ temp = *txp;
writel(temp, ®s->tx_data);
- out_bytes--;
+ out_bytes -= step;
+ if (txp)
+ txp += step;
+ tx_lvl += step;
}
- if (rx_lvl > 0) {
- temp = readl(®s->rx_data);
- if (spi_slave->skip_preamble) {
- if (temp == SPI_PREAMBLE_END_BYTE) {
- spi_slave->skip_preamble = 0;
- stopping = 0;
+ if (rx_lvl >= step) {
+ while (rx_lvl >= step) {
+ temp = readl(®s->rx_data);
+ if (spi_slave->skip_preamble) {
+ if (temp == SPI_PREAMBLE_END_BYTE) {
+ spi_slave->skip_preamble = 0;
+ stopping = 0;
+ }
+ } else {
+ if (rxp || stopping) {
+ *rxp = temp;
+ rxp += step;
+ }
+ in_bytes -= step;
}
- } else {
- if (rxp || stopping)
- *rxp++ = temp;
- in_bytes--;
+ toread -= step;
+ rx_lvl -= step;
}
- toread--;
} else if (!toread) {
/*
* We have run out of input data, but haven't read
out_bytes = in_bytes;
toread = in_bytes;
txp = NULL;
- spi_request_bytes(regs, toread);
+ spi_request_bytes(regs, toread, step);
}
if (spi_slave->skip_preamble && get_timer(start) > 100) {
printf("SPI timeout: in_bytes=%d, out_bytes=%d, ",
if ((flags & SPI_XFER_BEGIN))
spi_cs_activate(slave);
- /* Exynos SPI limits each transfer to 65535 bytes */
+ /*
+ * Exynos SPI limits each transfer to 65535 transfers. To keep
+ * things simple, allow a maximum of 65532 bytes. We could allow
+ * more in word mode, but the performance difference is small.
+ */
bytelen = bitlen / 8;
for (upto = 0; !ret && upto < bytelen; upto += todo) {
- todo = min(bytelen - upto, (1 << 16) - 1);
+ todo = min(bytelen - upto, (1 << 16) - 4);
ret = spi_rx_tx(spi_slave, todo, &din, &dout, flags);
if (ret)
break;
{
struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
+ /* If it's too soon to do another transaction, wait */
+ if (spi_slave->bus->deactivate_delay_us &&
+ spi_slave->last_transaction_us) {
+ ulong delay_us; /* The delay completed so far */
+ delay_us = timer_get_us() - spi_slave->last_transaction_us;
+ if (delay_us < spi_slave->bus->deactivate_delay_us)
+ udelay(spi_slave->bus->deactivate_delay_us - delay_us);
+ }
+
clrbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT);
debug("Activate CS, bus %d\n", spi_slave->slave.bus);
spi_slave->skip_preamble = spi_slave->mode & SPI_PREAMBLE;
+
+ /* Remember time of this transaction so we can honour the bus delay */
+ if (spi_slave->bus->deactivate_delay_us)
+ spi_slave->last_transaction_us = timer_get_us();
}
/**
/* Use 500KHz as a suitable default */
bus->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
500000);
+ bus->deactivate_delay_us = fdtdec_get_int(blob, node,
+ "spi-deactivate-delay", 0);
return 0;
}
* @param node SPI peripheral node to use
* @return 0 if ok, -1 on error
*/
-struct spi_slave *spi_setup_slave_fdt(const void *blob, int node,
- unsigned int cs, unsigned int max_hz, unsigned int mode)
+struct spi_slave *spi_setup_slave_fdt(const void *blob, int slave_node,
+ int spi_node)
{
struct spi_bus *bus;
unsigned int i;
for (i = 0, bus = spi_bus; i < bus_count; i++, bus++) {
- if (bus->node == node)
- return spi_setup_slave(i, cs, max_hz, mode);
+ if (bus->node == spi_node)
+ return spi_base_setup_slave_fdt(blob, i, slave_node);
}
- debug("%s: Failed to find bus node %d\n", __func__, node);
+ debug("%s: Failed to find bus node %d\n", __func__, spi_node);
return NULL;
}
projects / karo-tx-uboot.git / blobdiff