This patch adds support to the FPGA manager for configuring the SRAM of
iCE40LM, iCE40LP, iCE40HX, iCE40 Ultra, iCE40 UltraLite and iCE40
UltraPlus devices, through slave SPI.
Signed-off-by: Joel Holdsworth <joel@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Marek Vasut <marex@xxxxxxx>
Reviewed-by: Moritz Fischer <moritz.fischer@xxxxxxxxx>
Acked-by: Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/fpga/Kconfig | 6 ++
drivers/fpga/Makefile | 1 +
drivers/fpga/ice40-spi.c | 207 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 214 insertions(+)
create mode 100644 drivers/fpga/ice40-spi.c
diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index ce861a2..967cda4 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -20,6 +20,12 @@ config FPGA_REGION
FPGA Regions allow loading FPGA images under control of
the Device Tree.
+config FPGA_MGR_ICE40_SPI
+ tristate "Lattice iCE40 SPI"
+ depends on OF && SPI
+ help
+ FPGA manager driver support for Lattice iCE40 FPGAs over SPI.
+
config FPGA_MGR_SOCFPGA
tristate "Altera SOCFPGA FPGA Manager"
depends on ARCH_SOCFPGA || COMPILE_TEST
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index 8df07bc..cc0d364 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -6,6 +6,7 @@
obj-$(CONFIG_FPGA) += fpga-mgr.o
# FPGA Manager Drivers
+obj-$(CONFIG_FPGA_MGR_ICE40_SPI) += ice40-spi.o
obj-$(CONFIG_FPGA_MGR_SOCFPGA) += socfpga.o
obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10) += socfpga-a10.o
obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA) += zynq-fpga.o
diff --git a/drivers/fpga/ice40-spi.c b/drivers/fpga/ice40-spi.c
new file mode 100644
index 0000000..6a4194b
--- /dev/null
+++ b/drivers/fpga/ice40-spi.c
@@ -0,0 +1,207 @@
+/*
+ * 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;
+}
+
+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;
+}
+
+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);
+}
+
+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));
+}
+
+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: %ld\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: %ld\n", ret);
+ return ret;
+ }
+
+ /* Register with the FPGA manager */
+ return fpga_mgr_register(dev, "Lattice iCE40 FPGA Manager",
+ &ice40_fpga_ops, priv);
+}
+
+static int ice40_fpga_remove(struct spi_device *spi)
+{
+ fpga_mgr_unregister(&spi->dev);
+ return 0;
+}
+
+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@xxxxxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Lattice iCE40 FPGA Manager");
+MODULE_LICENSE("GPL v2");
--
2.7.4
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