diff options
Diffstat (limited to 'drivers/fpga/xilinx-spi.c')
| -rw-r--r-- | drivers/fpga/xilinx-spi.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c new file mode 100644 index 000000000000..9b62a4c2a3df --- /dev/null +++ b/drivers/fpga/xilinx-spi.c @@ -0,0 +1,198 @@ +/* + * 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"); |