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spi: dw: Add mem_ops

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The designware ssi device has "broken" chip select behaviour [1], and needs
specific manipulation to use the built-in chip select. The existing fix is
to use an external GPIO for chip select, but typically the K210 has SPI3
directly connected to a flash chip with dedicated pins. This makes it
impossible to use the spi_xfer function to use spi, since the CS is
de-asserted in between calls.  This patch adds an implementation of
exec_op, which gives correct behaviour when reading/writing spi flash.

This patch also rearranges the headers to conform to U-Boot style.

[1] https://lkml.org/lkml/2015/12/23/132

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Tested-by Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
This commit is contained in:
Sean Anderson 2020-10-16 18:57:53 -04:00 committed by Jagan Teki
parent 0d98f6de62
commit fec7bf0460
1 changed files with 113 additions and 9 deletions
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122
drivers/spi/designware_spi.c
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@ -12,21 +12,23 @@
#define LOG_CATEGORY UCLASS_SPI
#include <common.h>
#include <log.h>
#include <asm-generic/gpio.h>
#include <clk.h>
#include <dm.h>
#include <errno.h>
#include <malloc.h>
#include <spi.h>
#include <fdtdec.h>
#include <reset.h>
#include <dm/device_compat.h>
#include <linux/bitops.h>
#include <errno.h>
#include <fdtdec.h>
#include <log.h>
#include <malloc.h>
#include <reset.h>
#include <spi.h>
#include <spi-mem.h>
#include <asm/io.h>
#include <asm-generic/gpio.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/compat.h>
#include <linux/iopoll.h>
#include <asm/io.h>
#include <linux/sizes.h>
/* Register offsets */
#define DW_SPI_CTRLR0 0x00
@ -560,6 +562,107 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen,
return ret;
}
/*
* This function is necessary for reading SPI flash with the native CS
* c.f. https://lkml.org/lkml/2015/12/23/132
*/
static int dw_spi_exec_op(struct spi_slave *slave, const struct spi_mem_op *op)
{
bool read = op->data.dir == SPI_MEM_DATA_IN;
int pos, i, ret = 0;
struct udevice *bus = slave->dev->parent;
struct dw_spi_priv *priv = dev_get_priv(bus);
u8 op_len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
u8 op_buf[op_len];
u32 cr0;
if (read)
priv->tmode = CTRLR0_TMOD_EPROMREAD;
else
priv->tmode = CTRLR0_TMOD_TO;
cr0 = priv->update_cr0(priv);
dev_dbg(bus, "cr0=%08x buf=%p len=%u [bytes]\n", cr0, op->data.buf.in,
op->data.nbytes);
dw_write(priv, DW_SPI_SSIENR, 0);
dw_write(priv, DW_SPI_CTRLR0, cr0);
if (read)
dw_write(priv, DW_SPI_CTRLR1, op->data.nbytes - 1);
dw_write(priv, DW_SPI_SSIENR, 1);
/* From spi_mem_exec_op */
pos = 0;
op_buf[pos++] = op->cmd.opcode;
if (op->addr.nbytes) {
for (i = 0; i < op->addr.nbytes; i++)
op_buf[pos + i] = op->addr.val >>
(8 * (op->addr.nbytes - i - 1));
pos += op->addr.nbytes;
}
if (op->dummy.nbytes)
memset(op_buf + pos, 0xff, op->dummy.nbytes);
external_cs_manage(slave->dev, false);
priv->tx = &op_buf;
priv->tx_end = priv->tx + op_len;
priv->rx = NULL;
priv->rx_end = NULL;
while (priv->tx != priv->tx_end)
dw_writer(priv);
/*
* XXX: The following are tight loops! Enabling debug messages may cause
* them to fail because we are not reading/writing the fifo fast enough.
*/
if (read) {
priv->rx = op->data.buf.in;
priv->rx_end = priv->rx + op->data.nbytes;
dw_write(priv, DW_SPI_SER, 1 << spi_chip_select(slave->dev));
while (priv->rx != priv->rx_end)
dw_reader(priv);
} else {
u32 val;
priv->tx = op->data.buf.out;
priv->tx_end = priv->tx + op->data.nbytes;
/* Fill up the write fifo before starting the transfer */
dw_writer(priv);
dw_write(priv, DW_SPI_SER, 1 << spi_chip_select(slave->dev));
while (priv->tx != priv->tx_end)
dw_writer(priv);
if (readl_poll_timeout(priv->regs + DW_SPI_SR, val,
(val & SR_TF_EMPT) && !(val & SR_BUSY),
RX_TIMEOUT * 1000)) {
ret = -ETIMEDOUT;
}
}
dw_write(priv, DW_SPI_SER, 0);
external_cs_manage(slave->dev, true);
dev_dbg(bus, "%u bytes xfered\n", op->data.nbytes);
return ret;
}
/* The size of ctrl1 limits data transfers to 64K */
static int dw_spi_adjust_op_size(struct spi_slave *slave, struct spi_mem_op *op)
{
op->data.nbytes = min(op->data.nbytes, (unsigned int)SZ_64K);
return 0;
}
static const struct spi_controller_mem_ops dw_spi_mem_ops = {
.exec_op = dw_spi_exec_op,
.adjust_op_size = dw_spi_adjust_op_size,
};
static int dw_spi_set_speed(struct udevice *bus, uint speed)
{
struct dw_spi_platdata *plat = dev_get_platdata(bus);
@ -624,6 +727,7 @@ static int dw_spi_remove(struct udevice *bus)
static const struct dm_spi_ops dw_spi_ops = {
.xfer = dw_spi_xfer,
.mem_ops = &dw_spi_mem_ops,
.set_speed = dw_spi_set_speed,
.set_mode = dw_spi_set_mode,
/*