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Release 4.17 drivers/fpga/ice40-spi.c

Directory: drivers/fpga
/*
 * FPGA Manager Driver for Lattice iCE40.
 *
 *  Copyright (c) 2016 Joel Holdsworth
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This driver adds support to the FPGA manager for configuring the SRAM of
 * Lattice iCE40 FPGAs through slave SPI.
 */

#include <linux/fpga/fpga-mgr.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/spi/spi.h>
#include <linux/stringify.h>


#define ICE40_SPI_MAX_SPEED 25000000 
/* Hz */

#define ICE40_SPI_MIN_SPEED 1000000 
/* Hz */


#define ICE40_SPI_RESET_DELAY 1 
/* us (>200ns) */

#define ICE40_SPI_HOUSEKEEPING_DELAY 1200 
/* us */


#define ICE40_SPI_NUM_ACTIVATION_BYTES DIV_ROUND_UP(49, 8)


struct ice40_fpga_priv {
	
struct spi_device *dev;
	
struct gpio_desc *reset;
	
struct gpio_desc *cdone;
};


static enum fpga_mgr_states ice40_fpga_ops_state(struct fpga_manager *mgr) { struct ice40_fpga_priv *priv = mgr->priv; return gpiod_get_value(priv->cdone) ? FPGA_MGR_STATE_OPERATING : FPGA_MGR_STATE_UNKNOWN; }

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Joel Holdsworth33100.00%1100.00%
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static int ice40_fpga_ops_write_init(struct fpga_manager *mgr, struct fpga_image_info *info, const char *buf, size_t count) { struct ice40_fpga_priv *priv = mgr->priv; struct spi_device *dev = priv->dev; struct spi_message message; struct spi_transfer assert_cs_then_reset_delay = { .cs_change = 1, .delay_usecs = ICE40_SPI_RESET_DELAY }; struct spi_transfer housekeeping_delay_then_release_cs = { .delay_usecs = ICE40_SPI_HOUSEKEEPING_DELAY }; int ret; if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) { dev_err(&dev->dev, "Partial reconfiguration is not supported\n"); return -ENOTSUPP; } /* Lock the bus, assert CRESET_B and SS_B and delay >200ns */ spi_bus_lock(dev->master); gpiod_set_value(priv->reset, 1); spi_message_init(&message); spi_message_add_tail(&assert_cs_then_reset_delay, &message); ret = spi_sync_locked(dev, &message); /* Come out of reset */ gpiod_set_value(priv->reset, 0); /* Abort if the chip-select failed */ if (ret) goto fail; /* Check CDONE is de-asserted i.e. the FPGA is reset */ if (gpiod_get_value(priv->cdone)) { dev_err(&dev->dev, "Device reset failed, CDONE is asserted\n"); ret = -EIO; goto fail; } /* Wait for the housekeeping to complete, and release SS_B */ spi_message_init(&message); spi_message_add_tail(&housekeeping_delay_then_release_cs, &message); ret = spi_sync_locked(dev, &message); fail: spi_bus_unlock(dev->master); return ret; }

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static int ice40_fpga_ops_write(struct fpga_manager *mgr, const char *buf, size_t count) { struct ice40_fpga_priv *priv = mgr->priv; return spi_write(priv->dev, buf, count); }

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Joel Holdsworth40100.00%1100.00%
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static int ice40_fpga_ops_write_complete(struct fpga_manager *mgr, struct fpga_image_info *info) { struct ice40_fpga_priv *priv = mgr->priv; struct spi_device *dev = priv->dev; const u8 padding[ICE40_SPI_NUM_ACTIVATION_BYTES] = {0}; /* Check CDONE is asserted */ if (!gpiod_get_value(priv->cdone)) { dev_err(&dev->dev, "CDONE was not asserted after firmware transfer\n"); return -EIO; } /* Send of zero-padding to activate the firmware */ return spi_write(dev, padding, sizeof(padding)); }

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Joel Holdsworth86100.00%1100.00%
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static const struct fpga_manager_ops ice40_fpga_ops = { .state = ice40_fpga_ops_state, .write_init = ice40_fpga_ops_write_init, .write = ice40_fpga_ops_write, .write_complete = ice40_fpga_ops_write_complete, };
static int ice40_fpga_probe(struct spi_device *spi) { struct device *dev = &spi->dev; struct ice40_fpga_priv *priv; int ret; priv = devm_kzalloc(&spi->dev, sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; priv->dev = spi; /* Check board setup data. */ if (spi->max_speed_hz > ICE40_SPI_MAX_SPEED) { dev_err(dev, "SPI speed is too high, maximum speed is " __stringify(ICE40_SPI_MAX_SPEED) "\n"); return -EINVAL; } if (spi->max_speed_hz < ICE40_SPI_MIN_SPEED) { dev_err(dev, "SPI speed is too low, minimum speed is " __stringify(ICE40_SPI_MIN_SPEED) "\n"); return -EINVAL; } if (spi->mode & SPI_CPHA) { dev_err(dev, "Bad SPI mode, CPHA not supported\n"); return -EINVAL; } /* Set up the GPIOs */ priv->cdone = devm_gpiod_get(dev, "cdone", GPIOD_IN); if (IS_ERR(priv->cdone)) { ret = PTR_ERR(priv->cdone); dev_err(dev, "Failed to get CDONE GPIO: %d\n", ret); return ret; } priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); if (IS_ERR(priv->reset)) { ret = PTR_ERR(priv->reset); dev_err(dev, "Failed to get CRESET_B GPIO: %d\n", ret); return ret; } /* Register with the FPGA manager */ return fpga_mgr_register(dev, "Lattice iCE40 FPGA Manager", &ice40_fpga_ops, priv); }

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Joel Holdsworth241100.00%1100.00%
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static int ice40_fpga_remove(struct spi_device *spi) { fpga_mgr_unregister(&spi->dev); return 0; }

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Joel Holdsworth22100.00%1100.00%
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static const struct of_device_id ice40_fpga_of_match[] = { { .compatible = "lattice,ice40-fpga-mgr", }, {}, }; MODULE_DEVICE_TABLE(of, ice40_fpga_of_match); static struct spi_driver ice40_fpga_driver = { .probe = ice40_fpga_probe, .remove = ice40_fpga_remove, .driver = { .name = "ice40spi", .of_match_table = of_match_ptr(ice40_fpga_of_match), }, }; module_spi_driver(ice40_fpga_driver); MODULE_AUTHOR("Joel Holdsworth <joel@airwebreathe.org.uk>"); MODULE_DESCRIPTION("Lattice iCE40 FPGA Manager"); MODULE_LICENSE("GPL v2");

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Joel Holdsworth823100.00%1100.00%
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Directory: drivers/fpga
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