// SPDX-License-Identifier: GPL-2.0-or-later
// Copyright (C) IBM Corporation 2020
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/fsi.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/spi/spi.h>
#define FSI_ENGID_SPI 0x23
#define FSI_MBOX_ROOT_CTRL_8 0x2860
#define FSI_MBOX_ROOT_CTRL_8_SPI_MUX 0xf0000000
#define FSI2SPI_DATA0 0x00
#define FSI2SPI_DATA1 0x04
#define FSI2SPI_CMD 0x08
#define FSI2SPI_CMD_WRITE BIT(31)
#define FSI2SPI_RESET 0x18
#define FSI2SPI_STATUS 0x1c
#define FSI2SPI_STATUS_ANY_ERROR BIT(31)
#define FSI2SPI_IRQ 0x20
#define SPI_FSI_BASE 0x70000
#define SPI_FSI_INIT_TIMEOUT_MS 1000
#define SPI_FSI_MAX_XFR_SIZE 2048
#define SPI_FSI_MAX_XFR_SIZE_RESTRICTED 32
#define SPI_FSI_ERROR 0x0
#define SPI_FSI_COUNTER_CFG 0x1
#define SPI_FSI_COUNTER_CFG_LOOPS(x) (((u64)(x) & 0xffULL) << 32)
#define SPI_FSI_COUNTER_CFG_N2_RX BIT_ULL(8)
#define SPI_FSI_COUNTER_CFG_N2_TX BIT_ULL(9)
#define SPI_FSI_COUNTER_CFG_N2_IMPLICIT BIT_ULL(10)
#define SPI_FSI_COUNTER_CFG_N2_RELOAD BIT_ULL(11)
#define SPI_FSI_CFG1 0x2
#define SPI_FSI_CLOCK_CFG 0x3
#define SPI_FSI_CLOCK_CFG_MM_ENABLE BIT_ULL(32)
#define SPI_FSI_CLOCK_CFG_ECC_DISABLE (BIT_ULL(35) | BIT_ULL(33))
#define SPI_FSI_CLOCK_CFG_RESET1 (BIT_ULL(36) | BIT_ULL(38))
#define SPI_FSI_CLOCK_CFG_RESET2 (BIT_ULL(37) | BIT_ULL(39))
#define SPI_FSI_CLOCK_CFG_MODE (BIT_ULL(41) | BIT_ULL(42))
#define SPI_FSI_CLOCK_CFG_SCK_RECV_DEL GENMASK_ULL(51, 44)
#define SPI_FSI_CLOCK_CFG_SCK_NO_DEL BIT_ULL(51)
#define SPI_FSI_CLOCK_CFG_SCK_DIV GENMASK_ULL(63, 52)
#define SPI_FSI_MMAP 0x4
#define SPI_FSI_DATA_TX 0x5
#define SPI_FSI_DATA_RX 0x6
#define SPI_FSI_SEQUENCE 0x7
#define SPI_FSI_SEQUENCE_STOP 0x00
#define SPI_FSI_SEQUENCE_SEL_SLAVE(x) (0x10 | ((x) & 0xf))
#define SPI_FSI_SEQUENCE_SHIFT_OUT(x) (0x30 | ((x) & 0xf))
#define SPI_FSI_SEQUENCE_SHIFT_IN(x) (0x40 | ((x) & 0xf))
#define SPI_FSI_SEQUENCE_COPY_DATA_TX 0xc0
#define SPI_FSI_SEQUENCE_BRANCH(x) (0xe0 | ((x) & 0xf))
#define SPI_FSI_STATUS 0x8
#define SPI_FSI_STATUS_ERROR \
(GENMASK_ULL(31, 21) | GENMASK_ULL(15, 12))
#define SPI_FSI_STATUS_SEQ_STATE GENMASK_ULL(55, 48)
#define SPI_FSI_STATUS_SEQ_STATE_IDLE BIT_ULL(48)
#define SPI_FSI_STATUS_TDR_UNDERRUN BIT_ULL(57)
#define SPI_FSI_STATUS_TDR_OVERRUN BIT_ULL(58)
#define SPI_FSI_STATUS_TDR_FULL BIT_ULL(59)
#define SPI_FSI_STATUS_RDR_UNDERRUN BIT_ULL(61)
#define SPI_FSI_STATUS_RDR_OVERRUN BIT_ULL(62)
#define SPI_FSI_STATUS_RDR_FULL BIT_ULL(63)
#define SPI_FSI_STATUS_ANY_ERROR \
(SPI_FSI_STATUS_ERROR | \
SPI_FSI_STATUS_TDR_OVERRUN | SPI_FSI_STATUS_RDR_UNDERRUN | \
SPI_FSI_STATUS_RDR_OVERRUN)
#define SPI_FSI_PORT_CTRL 0x9
struct fsi_spi {
struct device *dev; /* SPI controller device */
struct fsi_device *fsi; /* FSI2SPI CFAM engine device */
u32 base;
size_t max_xfr_size;
bool restricted;
};
struct fsi_spi_sequence {
int bit;
u64 data;
};
static int fsi_spi_check_mux(struct fsi_device *fsi, struct device *dev)
{
int rc;
u32 root_ctrl_8;
__be32 root_ctrl_8_be;
rc = fsi_slave_read(fsi->slave, FSI_MBOX_ROOT_CTRL_8, &root_ctrl_8_be,
sizeof(root_ctrl_8_be));
if (rc)
return rc;
root_ctrl_8 = be32_to_cpu(root_ctrl_8_be);
dev_dbg(dev, "Root control register 8: %08x\n", root_ctrl_8);
if ((root_ctrl_8 & FSI_MBOX_ROOT_CTRL_8_SPI_MUX) ==
FSI_MBOX_ROOT_CTRL_8_SPI_MUX)
return 0;
return -ENOLINK;
}
static int fsi_spi_check_status(struct fsi_spi *ctx)
{
int rc;
u32 sts;
__be32 sts_be;
rc = fsi_device_read(ctx->fsi, FSI2SPI_STATUS, &sts_be,
sizeof(sts_be));
if (rc)
return rc;
sts = be32_to_cpu(sts_be);
if (sts & FSI2SPI_STATUS_ANY_ERROR) {
dev_err(ctx->dev, "Error with FSI2SPI interface: %08x.\n", sts);
return -EIO;
}
return 0;
}
static int fsi_spi_read_reg(struct fsi_spi *ctx, u32 offset, u64 *value)
{
int rc;
__be32 cmd_be;
__be32 data_be;
u32 cmd = offset + ctx->base;
*value = 0ULL;
if (cmd & FSI2SPI_CMD_WRITE)
return -EINVAL;
cmd_be = cpu_to_be32(cmd);
rc = fsi_device_write(ctx->fsi, FSI2SPI_CMD, &cmd_be, sizeof(cmd_be));
if (rc)
return rc;
rc = fsi_spi_check_status(ctx);
if (rc)
return rc;
rc = fsi_device_read(ctx->fsi, FSI2SPI_DATA0, &data_be,
sizeof(data_be));
if (rc)
return rc;
*value |= (u64)be32_to_cpu(data_be) << 32;
rc = fsi_device_read(ctx->fsi, FSI2SPI_DATA1, &data_be,
sizeof(data_be));
if (rc)
return rc;
*value |= (u64)be32_to_cpu(data_be);
dev_dbg(ctx->dev, "Read %02x[%016llx].\n", offset, *value);
return 0;
}
static int fsi_spi_write_reg(struct fsi_spi *ctx, u32 offset, u64 value)
{
int rc;
__be32 cmd_be;
__be32 data_be;
u32 cmd = offset + ctx->base;
if (cmd & FSI2SPI_CMD_WRITE)
return -EINVAL;
dev_dbg(ctx->dev, "Write %02x[%016llx].\n", offset, value);
data_be = cpu_to_be32(upper_32_bits(value));
rc = fsi_device_write(ctx->fsi, FSI2SPI_DATA0, &data_be,
sizeof(data_be));
if (rc)
return rc;
data_be = cpu_to_be32(lower_32_bits(value));
rc = fsi_device_write(ctx->fsi, FSI2SPI_DATA1, &data_be,
sizeof(data_be));
if (rc)
return rc;
cmd_be = cpu_to_be32(cmd | FSI2SPI_CMD_WRITE);
rc = fsi_device_write(ctx->fsi, FSI2SPI_CMD, &cmd_be, sizeof(cmd_be));
if (rc)
return rc;
return fsi_spi_check_status(ctx);
}
static int fsi_spi_data_in(u64 in, u8 *rx, int len)
{
int i;
int num_bytes = min(len, 8);
for (i = 0; i < num_bytes; ++i)
rx[i] = (u8)(in >> (8 * ((num_bytes - 1) - i)));
return num_bytes;
}
static int fsi_spi_data_out(u64 *out, const u8 *tx, int len)
{
int i;
int num_bytes = min(len, 8);
u8 *out_bytes = (u8 *)out;
/* Unused bytes of the tx data should be 0. */
*out = 0ULL;
for (i = 0; i < num_bytes; ++i)
out_bytes[8 - (i + 1)] = tx[i];
return num_bytes;
}
static int fsi_spi_reset(struct fsi_spi *ctx)
{
int rc;
dev_dbg(ctx->dev, "Resetting SPI controller.\n");
rc = fsi_spi_write_reg(ctx, SPI_FSI_CLOCK_CFG,
SPI_FSI_CLOCK_CFG_RESET1);
if (rc)
return rc;
rc = fsi_spi_write_reg(ctx, SPI_FSI_CLOCK_CFG,
SPI_FSI_CLOCK_CFG_RESET2);
if (rc)
return rc;
return fsi_spi_write_reg(ctx, SPI_FSI_STATUS, 0ULL);
}
static int fsi_spi_sequence_add(struct fsi_spi_sequence *seq, u8 val)
{
/*
* Add the next byte of instruction to the 8-byte sequence register.
* Then decrement the counter so that the next instruction will go in
* the right place. Return the index of the slot we just filled in the
* sequence register.
*/
seq->data |= (u64)val << seq->bit;
seq->bit -= 8;
return ((64 - seq->bit) / 8) - 2;
}
static void fsi_spi_sequence_init(struct fsi_spi_sequence *seq)
{
seq->bit = 56;
seq->data = 0ULL;
}
static int fsi_spi_sequence_transfer(struct fsi_spi *ctx,
struct fsi_spi_sequence *seq,
struct spi_transfer *transfer)
{
bool docfg = false;
int loops;
int idx;
int rc;
u8 val = 0;
u8 len = min(transfer->len, 8U);
u8 rem = transfer->len % len;
u64 cfg = 0ULL;
loops = transfer->len / len;
if (transfer->tx_buf) {
val = SPI_FSI_SEQUENCE_SHIFT_OUT(len);
idx = fsi_spi_sequence_add(seq, val);
if (rem)
rem = SPI_FSI_SEQUENCE_SHIFT_OUT(rem);
} else if (transfer->rx_buf) {
val = SPI_FSI_SEQUENCE_SHIFT_IN(len);
idx = fsi_spi_sequence_add(seq, val);
if (rem)
rem = SPI_FSI_SEQUENCE_SHIFT_IN(rem);
} else {
return -EINVAL;
}
if (ctx->restricted) {
const int eidx = rem ? 5 : 6;
while (loops > 1 && idx <= eidx) {
idx = fsi_spi_sequence_add(seq, val);
loops--;
docfg = true;
}
if (loops > 1) {
dev_warn(ctx->dev, "No sequencer slots; aborting.\n");
return -EINVAL;
}
}
if (loops > 1) {
fsi_spi_sequence_add(seq, SPI_FSI_SEQUENCE_BRANCH(idx));
docfg = true;
}
if (docfg) {
cfg = SPI_FSI_COUNTER_CFG_LOOPS(loops - 1);
if (transfer->rx_buf)
cfg |= SPI_FSI_COUNTER_CFG_N2_RX |
SPI_FSI_COUNTER_CFG_N2_TX |
SPI_FSI_COUNTER_CFG_N2_IMPLICIT |
SPI_FSI_COUNTER_CFG_N2_RELOAD;
rc = fsi_spi_write_reg(ctx, SPI_FSI_COUNTER_CFG, cfg);
if (rc)
return rc;
} else {
fsi_spi_write_reg(ctx, SPI_FSI_COUNTER_CFG, 0ULL);
}
if (rem)
fsi_spi_sequence_add(seq, rem);
return 0;
}
static int fsi_spi_transfer_data(struct fsi_spi *ctx,
struct spi_transfer *transfer)
{
int rc = 0;
u64 status = 0ULL;
u64 cfg = 0ULL;
if (transfer->tx_buf) {
int nb;
int sent = 0;
u64 out = 0ULL;
const u8 *tx = transfer->tx_buf;
while (transfer->len > sent) {
nb = fsi_spi_data_out(&out, &tx[sent],
(int)transfer->len - sent);
rc = fsi_spi_write_reg(ctx, SPI_FSI_DATA_TX, out);
if (rc)
return rc;
do {
rc = fsi_spi_read_reg(ctx, SPI_FSI_STATUS,
&status);
if (rc)
return rc;
if (status & SPI_FSI_STATUS_ANY_ERROR) {
rc = fsi_spi_reset(ctx);
if (rc)
return rc;
return -EREMOTEIO;
}
} while (status & SPI_FSI_STATUS_TDR_FULL);
sent += nb;
}
} else if (transfer->rx_buf) {
int recv = 0;
u64 in = 0ULL;
u8 *rx = transfer->rx_buf;
rc = fsi_spi_read_reg(ctx, SPI_FSI_COUNTER_CFG, &cfg);
if (rc)
return rc;
if (cfg & SPI_FSI_COUNTER_CFG_N2_IMPLICIT) {
rc = fsi_spi_write_reg(ctx, SPI_FSI_DATA_TX, 0);
if (rc)
return rc;
}
while (transfer->len > recv) {
do {
rc = fsi_spi_read_reg(ctx, SPI_FSI_STATUS,
&status);
if (rc)
return rc;
if (status & SPI_FSI_STATUS_ANY_ERROR) {
rc = fsi_spi_reset(ctx);
if (rc)
return rc;
return -EREMOTEIO;
}
} while (!(status & SPI_FSI_STATUS_RDR_FULL));
rc = fsi_spi_read_reg(ctx, SPI_FSI_DATA_RX, &in);
if (rc)
return rc;
recv += fsi_spi_data_in(in, &rx[recv],
(int)transfer->len - recv);
}
}
return 0;
}
static int fsi_spi_transfer_init(struct fsi_spi *ctx)
{
int rc;
bool reset = false;
unsigned long end;
u64 seq_state;
u64 clock_cfg = 0ULL;
u64 status = 0ULL;
u64 wanted_clock_cfg = SPI_FSI_CLOCK_CFG_ECC_DISABLE |
SPI_FSI_CLOCK_CFG_SCK_NO_DEL |
FIELD_PREP(SPI_FSI_CLOCK_CFG_SCK_DIV, 19);
end = jiffies + msecs_to_jiffies(SPI_FSI_INIT_TIMEOUT_MS);
do {
if (time_after(jiffies, end))
return -ETIMEDOUT;
rc = fsi_spi_read_reg(ctx, SPI_FSI_STATUS, &status);
if (rc)
return rc;
seq_state = status & SPI_FSI_STATUS_SEQ_STATE;
if (status & (SPI_FSI_STATUS_ANY_ERROR |
SPI_FSI_STATUS_TDR_FULL |
SPI_FSI_STATUS_RDR_FULL)) {
if (reset)
return -EIO;
rc = fsi_spi_reset(ctx);
if (rc)
return rc;
reset = true;
continue;
}
} while (seq_state && (seq_state != SPI_FSI_STATUS_SEQ_STATE_IDLE));
rc = fsi_spi_read_reg(ctx, SPI_FSI_CLOCK_CFG, &clock_cfg);
if (rc)
return rc;
if ((clock_cfg & (SPI_FSI_CLOCK_CFG_MM_ENABLE |
SPI_FSI_CLOCK_CFG_ECC_DISABLE |
SPI_FSI_CLOCK_CFG_MODE |
SPI_FSI_CLOCK_CFG_SCK_RECV_DEL |
SPI_FSI_CLOCK_CFG_SCK_DIV)) != wanted_clock_cfg)
rc = fsi_spi_write_reg(ctx, SPI_FSI_CLOCK_CFG,
wanted_clock_cfg);
return rc;
}
static int fsi_spi_transfer_one_message(struct spi_controller *ctlr,
struct spi_message *mesg)
{
int rc;
u8 seq_slave = SPI_FSI_SEQUENCE_SEL_SLAVE(mesg->spi->chip_select + 1);
struct spi_transfer *transfer;
struct fsi_spi *ctx = spi_controller_get_devdata(ctlr);
rc = fsi_spi_check_mux(ctx->fsi, ctx->dev);
if (rc)
goto error;
list_for_each_entry(transfer, &mesg->transfers, transfer_list) {
struct fsi_spi_sequence seq;
struct spi_transfer *next = NULL;
/* Sequencer must do shift out (tx) first. */
if (!transfer->tx_buf ||
transfer->len > (ctx->max_xfr_size + 8)) {
rc = -EINVAL;
goto error;
}
dev_dbg(ctx->dev, "Start tx of %d bytes.\n", transfer->len);
rc = fsi_spi_transfer_init(ctx);
if (rc < 0)
goto error;
fsi_spi_sequence_init(&seq);
fsi_spi_sequence_add(&seq, seq_slave);
rc = fsi_spi_sequence_transfer(ctx, &seq, transfer);
if (rc)
goto error;
if (!list_is_last(&transfer->transfer_list,
&mesg->transfers)) {
next = list_next_entry(transfer, transfer_list);
/* Sequencer can only do shift in (rx) after tx. */
if (next->rx_buf) {
if (next->len > ctx->max_xfr_size) {
rc = -EINVAL;
goto error;
}
dev_dbg(ctx->dev, "Sequence rx of %d bytes.\n",
next->len);
rc = fsi_spi_sequence_transfer(ctx, &seq,
next);
if (rc)
goto error;
} else {
next = NULL;
}
}
fsi_spi_sequence_add(&seq, SPI_FSI_SEQUENCE_SEL_SLAVE(0));
rc = fsi_spi_write_reg(ctx, SPI_FSI_SEQUENCE, seq.data);
if (rc)
goto error;
rc = fsi_spi_transfer_data(ctx, transfer);
if (rc)
goto error;
if (next) {
rc = fsi_spi_transfer_data(ctx, next);
if (rc)
goto error;
transfer = next;
}
}
error:
mesg->status = rc;
spi_finalize_current_message(ctlr);
return rc;
}
static size_t fsi_spi_max_transfer_size(struct spi_device *spi)
{
struct fsi_spi *ctx = spi_controller_get_devdata(spi->controller);
return ctx->max_xfr_size;
}
static int fsi_spi_probe(struct device *dev)
{
int rc;
struct device_node *np;
int num_controllers_registered = 0;
struct fsi_device *fsi = to_fsi_dev(dev);
rc = fsi_spi_check_mux(fsi, dev);
if (rc)
return -ENODEV;
for_each_available_child_of_node(dev->of_node, np) {
u32 base;
struct fsi_spi *ctx;
struct spi_controller *ctlr;
if (of_property_read_u32(np, "reg", &base))
continue;
ctlr = spi_alloc_master(dev, sizeof(*ctx));
if (!ctlr)
break;
ctlr->dev.of_node = np;
ctlr->num_chipselect = of_get_available_child_count(np) ?: 1;
ctlr->flags = SPI_CONTROLLER_HALF_DUPLEX;
ctlr->max_transfer_size = fsi_spi_max_transfer_size;
ctlr->transfer_one_message = fsi_spi_transfer_one_message;
ctx = spi_controller_get_devdata(ctlr);
ctx->dev = &ctlr->dev;
ctx->fsi = fsi;
ctx->base = base + SPI_FSI_BASE;
if (of_device_is_compatible(np, "ibm,fsi2spi-restricted")) {
ctx->restricted = true;
ctx->max_xfr_size = SPI_FSI_MAX_XFR_SIZE_RESTRICTED;
} else {
ctx->restricted = false;
ctx->max_xfr_size = SPI_FSI_MAX_XFR_SIZE;
}
rc = devm_spi_register_controller(dev, ctlr);
if (rc)
spi_controller_put(ctlr);
else
num_controllers_registered++;
}
if (!num_controllers_registered)
return -ENODEV;
return 0;
}
static const struct fsi_device_id fsi_spi_ids[] = {
{ FSI_ENGID_SPI, FSI_VERSION_ANY },
{ }
};
MODULE_DEVICE_TABLE(fsi, fsi_spi_ids);
static struct fsi_driver fsi_spi_driver = {
.id_table = fsi_spi_ids,
.drv = {
.name = "spi-fsi",
.bus = &fsi_bus_type,
.probe = fsi_spi_probe,
},
};
module_fsi_driver(fsi_spi_driver);
MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
MODULE_DESCRIPTION("FSI attached SPI controller");
MODULE_LICENSE("GPL");