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// SPDX-License-Identifier: GPL-2.0
/*
* Greybus SPI library
*
* Copyright 2014-2016 Google Inc.
* Copyright 2014-2016 Linaro Ltd.
*/
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/greybus.h>
#include <linux/spi/spi.h>
#include "spilib.h"
struct gb_spilib {
struct gb_connection *connection;
struct device *parent;
struct spi_transfer *first_xfer;
struct spi_transfer *last_xfer;
struct spilib_ops *ops;
u32 rx_xfer_offset;
u32 tx_xfer_offset;
u32 last_xfer_size;
unsigned int op_timeout;
u16 mode;
u16 flags;
u32 bits_per_word_mask;
u8 num_chipselect;
u32 min_speed_hz;
u32 max_speed_hz;
};
#define GB_SPI_STATE_MSG_DONE ((void *)0)
#define GB_SPI_STATE_MSG_IDLE ((void *)1)
#define GB_SPI_STATE_MSG_RUNNING ((void *)2)
#define GB_SPI_STATE_OP_READY ((void *)3)
#define GB_SPI_STATE_OP_DONE ((void *)4)
#define GB_SPI_STATE_MSG_ERROR ((void *)-1)
#define XFER_TIMEOUT_TOLERANCE 200
static struct spi_master *get_master_from_spi(struct gb_spilib *spi)
{
return gb_connection_get_data(spi->connection);
}
static int tx_header_fit_operation(u32 tx_size, u32 count, size_t data_max)
{
size_t headers_size;
data_max -= sizeof(struct gb_spi_transfer_request);
headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
return tx_size + headers_size > data_max ? 0 : 1;
}
static size_t calc_rx_xfer_size(u32 rx_size, u32 *tx_xfer_size, u32 len,
size_t data_max)
{
size_t rx_xfer_size;
data_max -= sizeof(struct gb_spi_transfer_response);
if (rx_size + len > data_max)
rx_xfer_size = data_max - rx_size;
else
rx_xfer_size = len;
/* if this is a write_read, for symmetry read the same as write */
if (*tx_xfer_size && rx_xfer_size > *tx_xfer_size)
rx_xfer_size = *tx_xfer_size;
if (*tx_xfer_size && rx_xfer_size < *tx_xfer_size)
*tx_xfer_size = rx_xfer_size;
return rx_xfer_size;
}
static size_t calc_tx_xfer_size(u32 tx_size, u32 count, size_t len,
size_t data_max)
{
size_t headers_size;
data_max -= sizeof(struct gb_spi_transfer_request);
headers_size = (count + 1) * sizeof(struct gb_spi_transfer);
if (tx_size + headers_size + len > data_max)
return data_max - (tx_size + sizeof(struct gb_spi_transfer));
return len;
}
static void clean_xfer_state(struct gb_spilib *spi)
{
spi->first_xfer = NULL;
spi->last_xfer = NULL;
spi->rx_xfer_offset = 0;
spi->tx_xfer_offset = 0;
spi->last_xfer_size = 0;
spi->op_timeout = 0;
}
static bool is_last_xfer_done(struct gb_spilib *spi)
{
struct spi_transfer *last_xfer = spi->last_xfer;
if ((spi->tx_xfer_offset + spi->last_xfer_size == last_xfer->len) ||
(spi->rx_xfer_offset + spi->last_xfer_size == last_xfer->len))
return true;
return false;
}
static int setup_next_xfer(struct gb_spilib *spi, struct spi_message *msg)
{
struct spi_transfer *last_xfer = spi->last_xfer;
if (msg->state != GB_SPI_STATE_OP_DONE)
return 0;
/*
* if we transferred all content of the last transfer, reset values and
* check if this was the last transfer in the message
*/
if (is_last_xfer_done(spi)) {
spi->tx_xfer_offset = 0;
spi->rx_xfer_offset = 0;
spi->op_timeout = 0;
if (last_xfer == list_last_entry(&msg->transfers,
struct spi_transfer,
transfer_list))
msg->state = GB_SPI_STATE_MSG_DONE;
else
spi->first_xfer = list_next_entry(last_xfer,
transfer_list);
return 0;
}
spi->first_xfer = last_xfer;
if (last_xfer->tx_buf)
spi->tx_xfer_offset += spi->last_xfer_size;
if (last_xfer->rx_buf)
spi->rx_xfer_offset += spi->last_xfer_size;
return 0;
}
static struct spi_transfer *get_next_xfer(struct spi_transfer *xfer,
struct spi_message *msg)
{
if (xfer == list_last_entry(&msg->transfers, struct spi_transfer,
transfer_list))
return NULL;
return list_next_entry(xfer, transfer_list);
}
/* Routines to transfer data */
static struct gb_operation *gb_spi_operation_create(struct gb_spilib *spi,
struct gb_connection *connection, struct spi_message *msg)
{
struct gb_spi_transfer_request *request;
struct spi_device *dev = msg->spi;
struct spi_transfer *xfer;
struct gb_spi_transfer *gb_xfer;
struct gb_operation *operation;
u32 tx_size = 0, rx_size = 0, count = 0, xfer_len = 0, request_size;
u32 tx_xfer_size = 0, rx_xfer_size = 0, len;
u32 total_len = 0;
unsigned int xfer_timeout;
size_t data_max;
void *tx_data;
data_max = gb_operation_get_payload_size_max(connection);
xfer = spi->first_xfer;
/* Find number of transfers queued and tx/rx length in the message */
while (msg->state != GB_SPI_STATE_OP_READY) {
msg->state = GB_SPI_STATE_MSG_RUNNING;
spi->last_xfer = xfer;
if (!xfer->tx_buf && !xfer->rx_buf) {
dev_err(spi->parent,
"bufferless transfer, length %u\n", xfer->len);
msg->state = GB_SPI_STATE_MSG_ERROR;
return NULL;
}
tx_xfer_size = 0;
rx_xfer_size = 0;
if (xfer->tx_buf) {
len = xfer->len - spi->tx_xfer_offset;
if (!tx_header_fit_operation(tx_size, count, data_max))
break;
tx_xfer_size = calc_tx_xfer_size(tx_size, count,
len, data_max);
spi->last_xfer_size = tx_xfer_size;
}
if (xfer->rx_buf) {
len = xfer->len - spi->rx_xfer_offset;
rx_xfer_size = calc_rx_xfer_size(rx_size, &tx_xfer_size,
len, data_max);
spi->last_xfer_size = rx_xfer_size;
}
tx_size += tx_xfer_size;
rx_size += rx_xfer_size;
total_len += spi->last_xfer_size;
count++;
xfer = get_next_xfer(xfer, msg);
if (!xfer || total_len >= data_max)
msg->state = GB_SPI_STATE_OP_READY;
}
/*
* In addition to space for all message descriptors we need
* to have enough to hold all tx data.
*/
request_size = sizeof(*request);
request_size += count * sizeof(*gb_xfer);
request_size += tx_size;
/* Response consists only of incoming data */
operation = gb_operation_create(connection, GB_SPI_TYPE_TRANSFER,
request_size, rx_size, GFP_KERNEL);
if (!operation)
return NULL;
request = operation->request->payload;
request->count = cpu_to_le16(count);
request->mode = dev->mode;
request->chip_select = dev->chip_select;
gb_xfer = &request->transfers[0];
tx_data = gb_xfer + count; /* place tx data after last gb_xfer */
/* Fill in the transfers array */
xfer = spi->first_xfer;
while (msg->state != GB_SPI_STATE_OP_DONE) {
if (xfer == spi->last_xfer)
xfer_len = spi->last_xfer_size;
else
xfer_len = xfer->len;
/* make sure we do not timeout in a slow transfer */
xfer_timeout = xfer_len * 8 * MSEC_PER_SEC / xfer->speed_hz;
xfer_timeout += GB_OPERATION_TIMEOUT_DEFAULT;
if (xfer_timeout > spi->op_timeout)
spi->op_timeout = xfer_timeout;
gb_xfer->speed_hz = cpu_to_le32(xfer->speed_hz);
gb_xfer->len = cpu_to_le32(xfer_len);
gb_xfer->delay_usecs = cpu_to_le16(xfer->delay_usecs);
gb_xfer->cs_change = xfer->cs_change;
gb_xfer->bits_per_word = xfer->bits_per_word;
/* Copy tx data */
if (xfer->tx_buf) {
gb_xfer->xfer_flags |= GB_SPI_XFER_WRITE;
memcpy(tx_data, xfer->tx_buf + spi->tx_xfer_offset,
xfer_len);
tx_data += xfer_len;
}
if (xfer->rx_buf)
gb_xfer->xfer_flags |= GB_SPI_XFER_READ;
if (xfer == spi->last_xfer) {
if (!is_last_xfer_done(spi))
gb_xfer->xfer_flags |= GB_SPI_XFER_INPROGRESS;
msg->state = GB_SPI_STATE_OP_DONE;
continue;
}
gb_xfer++;
xfer = get_next_xfer(xfer, msg);
}
msg->actual_length += total_len;
return operation;
}
static void gb_spi_decode_response(struct gb_spilib *spi,
struct spi_message *msg,
struct gb_spi_transfer_response *response)
{
struct spi_transfer *xfer = spi->first_xfer;
void *rx_data = response->data;
u32 xfer_len;
while (xfer) {
/* Copy rx data */
if (xfer->rx_buf) {
if (xfer == spi->first_xfer)
xfer_len = xfer->len - spi->rx_xfer_offset;
else if (xfer == spi->last_xfer)
xfer_len = spi->last_xfer_size;
else
xfer_len = xfer->len;
memcpy(xfer->rx_buf + spi->rx_xfer_offset, rx_data,
xfer_len);
rx_data += xfer_len;
}
if (xfer == spi->last_xfer)
break;
xfer = list_next_entry(xfer, transfer_list);
}
}
static int gb_spi_transfer_one_message(struct spi_master *master,
struct spi_message *msg)
{
struct gb_spilib *spi = spi_master_get_devdata(master);
struct gb_connection *connection = spi->connection;
struct gb_spi_transfer_response *response;
struct gb_operation *operation;
int ret = 0;
spi->first_xfer = list_first_entry_or_null(&msg->transfers,
struct spi_transfer,
transfer_list);
if (!spi->first_xfer) {
ret = -ENOMEM;
goto out;
}
msg->state = GB_SPI_STATE_MSG_IDLE;
while (msg->state != GB_SPI_STATE_MSG_DONE &&
msg->state != GB_SPI_STATE_MSG_ERROR) {
operation = gb_spi_operation_create(spi, connection, msg);
if (!operation) {
msg->state = GB_SPI_STATE_MSG_ERROR;
ret = -EINVAL;
continue;
}
ret = gb_operation_request_send_sync_timeout(operation,
spi->op_timeout);
if (!ret) {
response = operation->response->payload;
if (response)
gb_spi_decode_response(spi, msg, response);
} else {
dev_err(spi->parent,
"transfer operation failed: %d\n", ret);
msg->state = GB_SPI_STATE_MSG_ERROR;
}
gb_operation_put(operation);
setup_next_xfer(spi, msg);
}
out:
msg->status = ret;
clean_xfer_state(spi);
spi_finalize_current_message(master);
return ret;
}
static int gb_spi_prepare_transfer_hardware(struct spi_master *master)
{
struct gb_spilib *spi = spi_master_get_devdata(master);
return spi->ops->prepare_transfer_hardware(spi->parent);
}
static int gb_spi_unprepare_transfer_hardware(struct spi_master *master)
{
struct gb_spilib *spi = spi_master_get_devdata(master);
spi->ops->unprepare_transfer_hardware(spi->parent);
return 0;
}
static int gb_spi_setup(struct spi_device *spi)
{
/* Nothing to do for now */
return 0;
}
static void gb_spi_cleanup(struct spi_device *spi)
{
/* Nothing to do for now */
}
/* Routines to get controller information */
/*
* Map Greybus spi mode bits/flags/bpw into Linux ones.
* All bits are same for now and so these macro's return same values.
*/
#define gb_spi_mode_map(mode) mode
#define gb_spi_flags_map(flags) flags
static int gb_spi_get_master_config(struct gb_spilib *spi)
{
struct gb_spi_master_config_response response;
u16 mode, flags;
int ret;
ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_MASTER_CONFIG,
NULL, 0, &response, sizeof(response));
if (ret < 0)
return ret;
mode = le16_to_cpu(response.mode);
spi->mode = gb_spi_mode_map(mode);
flags = le16_to_cpu(response.flags);
spi->flags = gb_spi_flags_map(flags);
spi->bits_per_word_mask = le32_to_cpu(response.bits_per_word_mask);
spi->num_chipselect = response.num_chipselect;
spi->min_speed_hz = le32_to_cpu(response.min_speed_hz);
spi->max_speed_hz = le32_to_cpu(response.max_speed_hz);
return 0;
}
static int gb_spi_setup_device(struct gb_spilib *spi, u8 cs)
{
struct spi_master *master = get_master_from_spi(spi);
struct gb_spi_device_config_request request;
struct gb_spi_device_config_response response;
struct spi_board_info spi_board = { {0} };
struct spi_device *spidev;
int ret;
u8 dev_type;
request.chip_select = cs;
ret = gb_operation_sync(spi->connection, GB_SPI_TYPE_DEVICE_CONFIG,
&request, sizeof(request),
&response, sizeof(response));
if (ret < 0)
return ret;
dev_type = response.device_type;
if (dev_type == GB_SPI_SPI_DEV)
strlcpy(spi_board.modalias, "spidev",
sizeof(spi_board.modalias));
else if (dev_type == GB_SPI_SPI_NOR)
strlcpy(spi_board.modalias, "spi-nor",
sizeof(spi_board.modalias));
else if (dev_type == GB_SPI_SPI_MODALIAS)
memcpy(spi_board.modalias, response.name,
sizeof(spi_board.modalias));
else
return -EINVAL;
spi_board.mode = le16_to_cpu(response.mode);
spi_board.bus_num = master->bus_num;
spi_board.chip_select = cs;
spi_board.max_speed_hz = le32_to_cpu(response.max_speed_hz);
spidev = spi_new_device(master, &spi_board);
if (!spidev)
return -EINVAL;
return 0;
}
int gb_spilib_master_init(struct gb_connection *connection, struct device *dev,
struct spilib_ops *ops)
{
struct gb_spilib *spi;
struct spi_master *master;
int ret;
u8 i;
/* Allocate master with space for data */
master = spi_alloc_master(dev, sizeof(*spi));
if (!master) {
dev_err(dev, "cannot alloc SPI master\n");
return -ENOMEM;
}
spi = spi_master_get_devdata(master);
spi->connection = connection;
gb_connection_set_data(connection, master);
spi->parent = dev;
spi->ops = ops;
/* get master configuration */
ret = gb_spi_get_master_config(spi);
if (ret)
goto exit_spi_put;
master->bus_num = -1; /* Allow spi-core to allocate it dynamically */
master->num_chipselect = spi->num_chipselect;
master->mode_bits = spi->mode;
master->flags = spi->flags;
master->bits_per_word_mask = spi->bits_per_word_mask;
/* Attach methods */
master->cleanup = gb_spi_cleanup;
master->setup = gb_spi_setup;
master->transfer_one_message = gb_spi_transfer_one_message;
if (ops && ops->prepare_transfer_hardware) {
master->prepare_transfer_hardware =
gb_spi_prepare_transfer_hardware;
}
if (ops && ops->unprepare_transfer_hardware) {
master->unprepare_transfer_hardware =
gb_spi_unprepare_transfer_hardware;
}
master->auto_runtime_pm = true;
ret = spi_register_master(master);
if (ret < 0)
goto exit_spi_put;
/* now, fetch the devices configuration */
for (i = 0; i < spi->num_chipselect; i++) {
ret = gb_spi_setup_device(spi, i);
if (ret < 0) {
dev_err(dev, "failed to allocate spi device %d: %d\n",
i, ret);
goto exit_spi_unregister;
}
}
return 0;
exit_spi_put:
spi_master_put(master);
return ret;
exit_spi_unregister:
spi_unregister_master(master);
return ret;
}
EXPORT_SYMBOL_GPL(gb_spilib_master_init);
void gb_spilib_master_exit(struct gb_connection *connection)
{
struct spi_master *master = gb_connection_get_data(connection);
spi_unregister_master(master);
}
EXPORT_SYMBOL_GPL(gb_spilib_master_exit);
MODULE_LICENSE("GPL v2");