linux/drivers/fpga/xilinx-spi.c
Luca Ceresoli 484a58607a fpga: fpga-mgr: xilinx-spi: fix error messages on -EPROBE_DEFER
The current code produces an error message on devm_gpiod_get() errors even
when the error is -EPROBE_DEFER, which should be silent.

This has been observed producing a significant amount of messages like:

    xlnx-slave-spi spi1.1: Failed to get PROGRAM_B gpio: -517

Fix and simplify code by using the dev_err_probe() helper function.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Fixes: dd2784c01d ("fpga manager: xilinx-spi: check INIT_B pin during write_init")
Fixes: 061c97d13f ("fpga manager: Add Xilinx slave serial SPI driver")
Signed-off-by: Moritz Fischer <mdf@kernel.org>
2021-03-06 07:39:17 -08:00

278 lines
6.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Xilinx Spartan6 and 7 Series Slave Serial SPI Driver
*
* Copyright (C) 2017 DENX Software Engineering
*
* Anatolij Gustschin <agust@denx.de>
*
* 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 *init_b;
struct gpio_desc *done;
};
static int get_done_gpio(struct fpga_manager *mgr)
{
struct xilinx_spi_conf *conf = mgr->priv;
int ret;
ret = gpiod_get_value(conf->done);
if (ret < 0)
dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret);
return ret;
}
static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
{
if (!get_done_gpio(mgr))
return FPGA_MGR_STATE_RESET;
return FPGA_MGR_STATE_UNKNOWN;
}
/**
* wait_for_init_b - wait for the INIT_B pin to have a given state, or wait
* a given delay if the pin is unavailable
*
* @mgr: The FPGA manager object
* @value: Value INIT_B to wait for (1 = asserted = low)
* @alt_udelay: Delay to wait if the INIT_B GPIO is not available
*
* Returns 0 when the INIT_B GPIO reached the given state or -ETIMEDOUT if
* too much time passed waiting for that. If no INIT_B GPIO is available
* then always return 0.
*/
static int wait_for_init_b(struct fpga_manager *mgr, int value,
unsigned long alt_udelay)
{
struct xilinx_spi_conf *conf = mgr->priv;
unsigned long timeout = jiffies + msecs_to_jiffies(1000);
if (conf->init_b) {
while (time_before(jiffies, timeout)) {
int ret = gpiod_get_value(conf->init_b);
if (ret == value)
return 0;
if (ret < 0) {
dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
return ret;
}
usleep_range(100, 400);
}
dev_err(&mgr->dev, "Timeout waiting for INIT_B to %s\n",
value ? "assert" : "deassert");
return -ETIMEDOUT;
}
udelay(alt_udelay);
return 0;
}
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;
int err;
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);
err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
if (err) {
gpiod_set_value(conf->prog_b, 0);
return err;
}
gpiod_set_value(conf->prog_b, 0);
err = wait_for_init_b(mgr, 0, 0);
if (err)
return err;
if (get_done_gpio(mgr)) {
dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
return -EIO;
}
/* program latency */
usleep_range(7500, 7600);
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 = jiffies + usecs_to_jiffies(info->config_complete_timeout_us);
bool expired = false;
int done;
int ret;
/*
* This loop is carefully written such that if the driver is
* scheduled out for more than 'timeout', we still check for DONE
* before giving up and we apply 8 extra CCLK cycles in all cases.
*/
while (!expired) {
expired = time_after(jiffies, timeout);
done = get_done_gpio(mgr);
if (done < 0)
return done;
ret = xilinx_spi_apply_cclk_cycles(conf);
if (ret)
return ret;
if (done)
return 0;
}
if (conf->init_b) {
ret = gpiod_get_value(conf->init_b);
if (ret < 0) {
dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
return ret;
}
dev_err(&mgr->dev,
ret ? "CRC error or invalid device\n"
: "Missing sync word or incomplete bitstream\n");
} else {
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;
struct fpga_manager *mgr;
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))
return dev_err_probe(&spi->dev, PTR_ERR(conf->prog_b),
"Failed to get PROGRAM_B gpio\n");
conf->init_b = devm_gpiod_get_optional(&spi->dev, "init-b", GPIOD_IN);
if (IS_ERR(conf->init_b))
return dev_err_probe(&spi->dev, PTR_ERR(conf->init_b),
"Failed to get INIT_B gpio\n");
conf->done = devm_gpiod_get(&spi->dev, "done", GPIOD_IN);
if (IS_ERR(conf->done))
return dev_err_probe(&spi->dev, PTR_ERR(conf->done),
"Failed to get DONE gpio\n");
mgr = devm_fpga_mgr_create(&spi->dev,
"Xilinx Slave Serial FPGA Manager",
&xilinx_spi_ops, conf);
if (!mgr)
return -ENOMEM;
return devm_fpga_mgr_register(&spi->dev, mgr);
}
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,
};
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");