diff options
Diffstat (limited to 'drivers/fpga/xilinx-core.c')
| -rw-r--r-- | drivers/fpga/xilinx-core.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/fpga/xilinx-core.c b/drivers/fpga/xilinx-core.c new file mode 100644 index 000000000000..39aeacf2e4f1 --- /dev/null +++ b/drivers/fpga/xilinx-core.c @@ -0,0 +1,229 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Common parts of the Xilinx Spartan6 and 7 Series FPGA manager drivers. + * + * Copyright (C) 2017 DENX Software Engineering + * + * Anatolij Gustschin <agust@denx.de> + */ + +#include "xilinx-core.h" + +#include <linux/delay.h> +#include <linux/fpga/fpga-mgr.h> +#include <linux/gpio/consumer.h> +#include <linux/of.h> + +static int get_done_gpio(struct fpga_manager *mgr) +{ + struct xilinx_fpga_core *core = mgr->priv; + int ret; + + ret = gpiod_get_value(core->done); + if (ret < 0) + dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret); + + return ret; +} + +static enum fpga_mgr_states xilinx_core_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_fpga_core *core = mgr->priv; + unsigned long timeout = jiffies + msecs_to_jiffies(1000); + + if (core->init_b) { + while (time_before(jiffies, timeout)) { + int ret = gpiod_get_value(core->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_core_write_init(struct fpga_manager *mgr, + struct fpga_image_info *info, const char *buf, + size_t count) +{ + struct xilinx_fpga_core *core = 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(core->prog_b, 1); + + err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */ + if (err) { + gpiod_set_value(core->prog_b, 0); + return err; + } + + gpiod_set_value(core->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_core_write(struct fpga_manager *mgr, const char *buf, + size_t count) +{ + struct xilinx_fpga_core *core = mgr->priv; + + return core->write(core, buf, count); +} + +static int xilinx_core_write_complete(struct fpga_manager *mgr, + struct fpga_image_info *info) +{ + struct xilinx_fpga_core *core = mgr->priv; + unsigned long timeout = + jiffies + usecs_to_jiffies(info->config_complete_timeout_us); + bool expired = false; + int done; + int ret; + const char padding[1] = { 0xff }; + + /* + * 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 = core->write(core, padding, sizeof(padding)); + if (ret) + return ret; + + if (done) + return 0; + } + + if (core->init_b) { + ret = gpiod_get_value(core->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 inline struct gpio_desc * +xilinx_core_devm_gpiod_get(struct device *dev, const char *con_id, + const char *legacy_con_id, enum gpiod_flags flags) +{ + struct gpio_desc *desc; + + desc = devm_gpiod_get(dev, con_id, flags); + if (IS_ERR(desc) && PTR_ERR(desc) == -ENOENT && + of_device_is_compatible(dev->of_node, "xlnx,fpga-slave-serial")) + desc = devm_gpiod_get(dev, legacy_con_id, flags); + + return desc; +} + +static const struct fpga_manager_ops xilinx_core_ops = { + .state = xilinx_core_state, + .write_init = xilinx_core_write_init, + .write = xilinx_core_write, + .write_complete = xilinx_core_write_complete, +}; + +int xilinx_core_probe(struct xilinx_fpga_core *core) +{ + struct fpga_manager *mgr; + + if (!core || !core->dev || !core->write) + return -EINVAL; + + /* PROGRAM_B is active low */ + core->prog_b = xilinx_core_devm_gpiod_get(core->dev, "prog", "prog_b", + GPIOD_OUT_LOW); + if (IS_ERR(core->prog_b)) + return dev_err_probe(core->dev, PTR_ERR(core->prog_b), + "Failed to get PROGRAM_B gpio\n"); + + core->init_b = xilinx_core_devm_gpiod_get(core->dev, "init", "init-b", + GPIOD_IN); + if (IS_ERR(core->init_b)) + return dev_err_probe(core->dev, PTR_ERR(core->init_b), + "Failed to get INIT_B gpio\n"); + + core->done = devm_gpiod_get(core->dev, "done", GPIOD_IN); + if (IS_ERR(core->done)) + return dev_err_probe(core->dev, PTR_ERR(core->done), + "Failed to get DONE gpio\n"); + + mgr = devm_fpga_mgr_register(core->dev, + "Xilinx Slave Serial FPGA Manager", + &xilinx_core_ops, core); + return PTR_ERR_OR_ZERO(mgr); +} +EXPORT_SYMBOL_GPL(xilinx_core_probe); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>"); +MODULE_DESCRIPTION("Xilinx 7 Series FPGA manager core"); |