[PATCH v10 1/3] of: Add vendor prefix for Lattice Semiconductor

[PATCH v10 1/3] of: Add vendor prefix for Lattice Semiconductor

[Joel Holdsworth]

Lattice Semiconductor Corporation is a manufacturer of integrated
circuits and IP products, including low-power FPGAs, video connectivity
devices and millimeter wave wireless products.

Website: http://latticesemi.com

Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Alan Tull <atull@opensource.altera.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
---
 Documentation/devicetree/bindings/vendor-prefixes.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 64fdc8c..7a87932 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -158,6 +158,7 @@ kosagi	Sutajio Ko-Usagi PTE Ltd.
 kyo	Kyocera Corporation
 lacie	LaCie
 lantiq	Lantiq Semiconductor
+lattice	Lattice Semiconductor
 lenovo	Lenovo Group Ltd.
 lg	LG Corporation
 linux	Linux-specific binding
-- 
2.7.4

[PATCH v10 2/3] Documentation: Add binding document for Lattice iCE40 FPGA manager

[Joel Holdsworth]

This adds documentation of the device tree bindings of the Lattice iCE40
FPGA driver for the FPGA manager framework.

Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Alan Tull <atull@opensource.altera.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Marek Vasut <marex@denx.de>
---
 .../bindings/fpga/lattice-ice40-fpga-mgr.txt        | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt

diff --git a/Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt b/Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt
new file mode 100644
index 0000000..7e7a78b
--- /dev/null
+++ b/Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt
@@ -0,0 +1,21 @@
+Lattice iCE40 FPGA Manager
+
+Required properties:
+- compatible:		Should contain "lattice,ice40-fpga-mgr"
+- reg:			SPI chip select
+- spi-max-frequency:	Maximum SPI frequency (>=1000000, <=25000000)
+- cdone-gpios:		GPIO input connected to CDONE pin
+- reset-gpios:		Active-low GPIO output connected to CRESET_B pin. Note
+			that unless the GPIO is held low during startup, the
+			FPGA will enter Master SPI mode and drive SCK with a
+			clock signal potentially jamming other devices on the
+			bus until the firmware is loaded.
+
+Example:
+	ice40: ice40@0 {
+		compatible = "lattice,ice40-fpga-mgr";
+		reg = <0>;
+		spi-max-frequency = <1000000>;
+		cdone-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>;
+		reset-gpios = <&gpio 22 GPIO_ACTIVE_LOW>;
+	};
-- 
2.7.4

[PATCH v10 3/3] fpga: Add support for Lattice iCE40 FPGAs

[Joel Holdsworth]

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@airwebreathe.org.uk>
Reviewed-by: Marek Vasut <marex@denx.de>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Acked-by: Alan Tull <atull@opensource.altera.com>
---
 drivers/fpga/Kconfig     |   6 ++
 drivers/fpga/Makefile    |   1 +
 drivers/fpga/ice40-spi.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 226 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..16ea2c6
--- /dev/null
+++ b/drivers/fpga/ice40-spi.c
@@ -0,0 +1,219 @@
+/*
+ * 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 device_node *np = spi->dev.of_node;
+	struct ice40_fpga_priv *priv;
+	int ret;
+
+	if (!np) {
+		dev_err(dev, "No Device Tree entry\n");
+		return -EINVAL;
+	}
+
+	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)) {
+		dev_err(dev, "Failed to get CDONE GPIO: %ld\n",
+			PTR_ERR(priv->cdone));
+		return -EINVAL;
+	}
+
+	priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(priv->reset)) {
+		dev_err(dev, "Failed to get CRESET_B GPIO: %ld\n",
+			PTR_ERR(priv->reset));
+		return -EINVAL;
+	}
+
+	/* Register with the FPGA manager */
+	ret = fpga_mgr_register(dev, "Lattice iCE40 FPGA Manager",
+				&ice40_fpga_ops, priv);
+	if (ret) {
+		dev_err(dev, "Unable to register FPGA manager");
+		return ret;
+	}
+
+	return 0;
+}
+
+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@airwebreathe.org.uk>");
+MODULE_DESCRIPTION("Lattice iCE40 FPGA Manager");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

Re: [PATCH v10 3/3] fpga: Add support for Lattice iCE40 FPGAs

[Vladimir Zapolskiy]

Hi Joel,

On 12/18/2016 07:33 AM, Joel Holdsworth wrote:
> 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@airwebreathe.org.uk>
> Reviewed-by: Marek Vasut <marex@denx.de>
> Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
> Acked-by: Alan Tull <atull@opensource.altera.com>
> ---

[snip]

> +
> +static int ice40_fpga_probe(struct spi_device *spi)
> +{
> +	struct device *dev = &spi->dev;
> +	struct device_node *np = spi->dev.of_node;

struct device_node *np = dev->of_node?

And actually I don't see why local variable 'np' is needed in the function,
see the next comment.

> +	struct ice40_fpga_priv *priv;
> +	int ret;
> +
> +	if (!np) {
> +		dev_err(dev, "No Device Tree entry\n");
> +		return -EINVAL;
> +	}

I would suggest to remove this check completely, I don't see a good
reason why it is needed.

> +
> +	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)) {
> +		dev_err(dev, "Failed to get CDONE GPIO: %ld\n",
> +			PTR_ERR(priv->cdone));
> +		return -EINVAL;

You should do 'return PTR_ERR(priv->cdone)' here, this will allow
to handle at lease -EPROBE_DEFER correctly.

> +	}
> +
> +	priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(priv->reset)) {
> +		dev_err(dev, "Failed to get CRESET_B GPIO: %ld\n",
> +			PTR_ERR(priv->reset));
> +		return -EINVAL;

Same as above.

> +	}
> +
> +	/* Register with the FPGA manager */
> +	ret = fpga_mgr_register(dev, "Lattice iCE40 FPGA Manager",
> +				&ice40_fpga_ops, priv);
> +	if (ret) {
> +		dev_err(dev, "Unable to register FPGA manager");
> +		return ret;

I would suggest to do just 'return fpga_mgr_register(dev, ....);' here,
if the driver is not registered, the core will let the user know about it.

> +	}
> +
> +	return 0;
> +}
> +

--
With best wishes,
Vladimir

Re: [PATCH v10 2/3] Documentation: Add binding document for Lattice iCE40 FPGA manager

[Geert Uytterhoeven]

Hi Joel,

On Sun, Dec 18, 2016 at 6:33 AM, Joel Holdsworth
<joel@airwebreathe.org.uk> wrote:
> This adds documentation of the device tree bindings of the Lattice iCE40
> FPGA driver for the FPGA manager framework.
>
> Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>
> Acked-by: Rob Herring <robh@kernel.org>
> Acked-by: Alan Tull <atull@opensource.altera.com>
> Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
> Acked-by: Marek Vasut <marex@denx.de>

> --- /dev/null
> +++ b/Documentation/devicetree/bindings/fpga/lattice-ice40-fpga-mgr.txt
> @@ -0,0 +1,21 @@
> +Lattice iCE40 FPGA Manager
> +
> +Required properties:
> +- compatible:          Should contain "lattice,ice40-fpga-mgr"
> +- reg:                 SPI chip select
> +- spi-max-frequency:   Maximum SPI frequency (>=1000000, <=25000000)
> +- cdone-gpios:         GPIO input connected to CDONE pin
> +- reset-gpios:         Active-low GPIO output connected to CRESET_B pin. Note
> +                       that unless the GPIO is held low during startup, the
> +                       FPGA will enter Master SPI mode and drive SCK with a
> +                       clock signal potentially jamming other devices on the
> +                       bus until the firmware is loaded.
> +
> +Example:
> +       ice40: ice40@0 {

As per ePAPR, node names should be generic names, e.g. "fpga@0".
Sorry for not noticing before.

> +               compatible = "lattice,ice40-fpga-mgr";
> +               reg = <0>;
> +               spi-max-frequency = <1000000>;
> +               cdone-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>;
> +               reset-gpios = <&gpio 22 GPIO_ACTIVE_LOW>;
> +       };

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds