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/*
* Xilinx Spartan6 Slave Serial SPI Driver
*
* Copyright (C) 2017 DENX Software Engineering
*
* Anatolij Gustschin <agust@denx.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* Manage Xilinx FPGA firmware that is loaded over SPI using
* the slave serial configuration interface.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/fpga/fpga-mgr.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/of.h>
#include <linux/spi/spi.h>
#include <linux/sizes.h>
struct xilinx_spi_conf {
struct spi_device *spi;
struct gpio_desc *prog_b;
struct gpio_desc *done;
};
static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
{
struct xilinx_spi_conf *conf = mgr->priv;
if (!gpiod_get_value(conf->done))
return FPGA_MGR_STATE_RESET;
return FPGA_MGR_STATE_UNKNOWN;
}
static int xilinx_spi_write_init(struct fpga_manager *mgr,
struct fpga_image_info *info,
const char *buf, size_t count)
{
struct xilinx_spi_conf *conf = mgr->priv;
const size_t prog_latency_7500us = 7500;
const size_t prog_pulse_1us = 1;
if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");
return -EINVAL;
}
gpiod_set_value(conf->prog_b, 1);
udelay(prog_pulse_1us); /* min is 500 ns */
gpiod_set_value(conf->prog_b, 0);
if (gpiod_get_value(conf->done)) {
dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
return -EIO;
}
/* program latency */
usleep_range(prog_latency_7500us, prog_latency_7500us + 100);
return 0;
}
static int xilinx_spi_write(struct fpga_manager *mgr, const char *buf,
size_t count)
{
struct xilinx_spi_conf *conf = mgr->priv;
const char *fw_data = buf;
const char *fw_data_end = fw_data + count;
while (fw_data < fw_data_end) {
size_t remaining, stride;
int ret;
remaining = fw_data_end - fw_data;
stride = min_t(size_t, remaining, SZ_4K);
ret = spi_write(conf->spi, fw_data, stride);
if (ret) {
dev_err(&mgr->dev, "SPI error in firmware write: %d\n",
ret);
return ret;
}
fw_data += stride;
}
return 0;
}
static int xilinx_spi_apply_cclk_cycles(struct xilinx_spi_conf *conf)
{
struct spi_device *spi = conf->spi;
const u8 din_data[1] = { 0xff };
int ret;
ret = spi_write(conf->spi, din_data, sizeof(din_data));
if (ret)
dev_err(&spi->dev, "applying CCLK cycles failed: %d\n", ret);
return ret;
}
static int xilinx_spi_write_complete(struct fpga_manager *mgr,
struct fpga_image_info *info)
{
struct xilinx_spi_conf *conf = mgr->priv;
unsigned long timeout;
int ret;
if (gpiod_get_value(conf->done))
return xilinx_spi_apply_cclk_cycles(conf);
timeout = jiffies + usecs_to_jiffies(info->config_complete_timeout_us);
while (time_before(jiffies, timeout)) {
ret = xilinx_spi_apply_cclk_cycles(conf);
if (ret)
return ret;
if (gpiod_get_value(conf->done))
return xilinx_spi_apply_cclk_cycles(conf);
}
dev_err(&mgr->dev, "Timeout after config data transfer.\n");
return -ETIMEDOUT;
}
static const struct fpga_manager_ops xilinx_spi_ops = {
.state = xilinx_spi_state,
.write_init = xilinx_spi_write_init,
.write = xilinx_spi_write,
.write_complete = xilinx_spi_write_complete,
};
static int xilinx_spi_probe(struct spi_device *spi)
{
struct xilinx_spi_conf *conf;
conf = devm_kzalloc(&spi->dev, sizeof(*conf), GFP_KERNEL);
if (!conf)
return -ENOMEM;
conf->spi = spi;
/* PROGRAM_B is active low */
conf->prog_b = devm_gpiod_get(&spi->dev, "prog_b", GPIOD_OUT_LOW);
if (IS_ERR(conf->prog_b)) {
dev_err(&spi->dev, "Failed to get PROGRAM_B gpio: %ld\n",
PTR_ERR(conf->prog_b));
return PTR_ERR(conf->prog_b);
}
conf->done = devm_gpiod_get(&spi->dev, "done", GPIOD_IN);
if (IS_ERR(conf->done)) {
dev_err(&spi->dev, "Failed to get DONE gpio: %ld\n",
PTR_ERR(conf->done));
return PTR_ERR(conf->done);
}
return fpga_mgr_register(&spi->dev, "Xilinx Slave Serial FPGA Manager",
&xilinx_spi_ops, conf);
}
static int xilinx_spi_remove(struct spi_device *spi)
{
fpga_mgr_unregister(&spi->dev);
return 0;
}
static const struct of_device_id xlnx_spi_of_match[] = {
{ .compatible = "xlnx,fpga-slave-serial", },
{}
};
MODULE_DEVICE_TABLE(of, xlnx_spi_of_match);
static struct spi_driver xilinx_slave_spi_driver = {
.driver = {
.name = "xlnx-slave-spi",
.of_match_table = of_match_ptr(xlnx_spi_of_match),
},
.probe = xilinx_spi_probe,
.remove = xilinx_spi_remove,
};
module_spi_driver(xilinx_slave_spi_driver)
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
MODULE_DESCRIPTION("Load Xilinx FPGA firmware over SPI");
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