FPGA: Add TS-7300 FPGA manager

Add support for loading bitstreams on the Altera Cyclone II FPGA
populated on the TS-7300 board. This is done through the configuration
and data registers offered through a memory interface between the EP93xx
SoC and the FPGA via an intermediate CPLD device.

The EP93xx SoC on the TS-7300 does not have direct means of configuring
the on-board FPGA other than by using the special memory mapped
interface to the CPLD. No other entity on the system can control the
FPGA bitstream.

Signed-off-by: Florian Fainelli <[e-mail]>
Acked-by: Alan Tull <[e-mail]>
Acked-by: Moritz Fischer <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/fpga/Kconfig

···
 	help
 	  FPGA manager driver support for Altera Arria10 SoCFPGA.
 
+config FPGA_MGR_TS73XX
+	tristate "Technologic Systems TS-73xx SBC FPGA Manager"
+	depends on ARCH_EP93XX && MACH_TS72XX
+	help
+	  FPGA manager driver support for the Altera Cyclone II FPGA
+	  present on the TS-73xx SBC boards.
+
 config FPGA_MGR_ZYNQ_FPGA
 	tristate "Xilinx Zynq FPGA"
 	depends on ARCH_ZYNQ || COMPILE_TEST

drivers/fpga/Makefile

···
 # FPGA Manager Drivers
 obj-$(CONFIG_FPGA_MGR_SOCFPGA)		+= socfpga.o
 obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10)	+= socfpga-a10.o
+obj-$(CONFIG_FPGA_MGR_TS73XX)		+= ts73xx-fpga.o
 obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)	+= zynq-fpga.o
 
 # FPGA Bridge Drivers

drivers/fpga/ts73xx-fpga.c

···
+/*
+ * Technologic Systems TS-73xx SBC FPGA loader
+ *
+ * Copyright (C) 2016 Florian Fainelli <[e-mail]>
+ *
+ * FPGA Manager Driver for the on-board Altera Cyclone II FPGA found on
+ * TS-7300, heavily based on load_fpga.c in their vendor tree.
+ *
+ * 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 program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/string.h>
+#include <linux/iopoll.h>
+#include <linux/fpga/fpga-mgr.h>
+
+#define TS73XX_FPGA_DATA_REG		0
+#define TS73XX_FPGA_CONFIG_REG		1
+
+#define TS73XX_FPGA_WRITE_DONE		0x1
+#define TS73XX_FPGA_WRITE_DONE_TIMEOUT	1000	/* us */
+#define TS73XX_FPGA_RESET		0x2
+#define TS73XX_FPGA_RESET_LOW_DELAY	30	/* us */
+#define TS73XX_FPGA_RESET_HIGH_DELAY	80	/* us */
+#define TS73XX_FPGA_LOAD_OK		0x4
+#define TS73XX_FPGA_CONFIG_LOAD		0x8
+
+struct ts73xx_fpga_priv {
+	void __iomem	*io_base;
+	struct device	*dev;
+};
+
+static enum fpga_mgr_states ts73xx_fpga_state(struct fpga_manager *mgr)
+{
+	return FPGA_MGR_STATE_UNKNOWN;
+}
+
+static int ts73xx_fpga_write_init(struct fpga_manager *mgr,
+				  struct fpga_image_info *info,
+				  const char *buf, size_t count)
+{
+	struct ts73xx_fpga_priv *priv = mgr->priv;
+
+	/* Reset the FPGA */
+	writeb(0, priv->io_base + TS73XX_FPGA_CONFIG_REG);
+	udelay(TS73XX_FPGA_RESET_LOW_DELAY);
+	writeb(TS73XX_FPGA_RESET, priv->io_base + TS73XX_FPGA_CONFIG_REG);
+	udelay(TS73XX_FPGA_RESET_HIGH_DELAY);
+
+	return 0;
+}
+
+static int ts73xx_fpga_write(struct fpga_manager *mgr, const char *buf,
+			     size_t count)
+{
+	struct ts73xx_fpga_priv *priv = mgr->priv;
+	size_t i = 0;
+	int ret;
+	u8 reg;
+
+	while (count--) {
+		ret = readb_poll_timeout(priv->io_base + TS73XX_FPGA_CONFIG_REG,
+					 reg, !(reg & TS73XX_FPGA_WRITE_DONE),
+					 1, TS73XX_FPGA_WRITE_DONE_TIMEOUT);
+		if (ret < 0)
+			return ret;
+
+		writeb(buf[i], priv->io_base + TS73XX_FPGA_DATA_REG);
+		i++;
+	}
+
+	return 0;
+}
+
+static int ts73xx_fpga_write_complete(struct fpga_manager *mgr,
+				      struct fpga_image_info *info)
+{
+	struct ts73xx_fpga_priv *priv = mgr->priv;
+	u8 reg;
+
+	usleep_range(1000, 2000);
+	reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
+	reg |= TS73XX_FPGA_CONFIG_LOAD;
+	writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
+
+	usleep_range(1000, 2000);
+	reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
+	reg &= ~TS73XX_FPGA_CONFIG_LOAD;
+	writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
+
+	reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
+	if ((reg & TS73XX_FPGA_LOAD_OK) != TS73XX_FPGA_LOAD_OK)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static const struct fpga_manager_ops ts73xx_fpga_ops = {
+	.state		= ts73xx_fpga_state,
+	.write_init	= ts73xx_fpga_write_init,
+	.write		= ts73xx_fpga_write,
+	.write_complete	= ts73xx_fpga_write_complete,
+};
+
+static int ts73xx_fpga_probe(struct platform_device *pdev)
+{
+	struct device *kdev = &pdev->dev;
+	struct ts73xx_fpga_priv *priv;
+	struct resource *res;
+
+	priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = kdev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->io_base = devm_ioremap_resource(kdev, res);
+	if (IS_ERR(priv->io_base)) {
+		dev_err(kdev, "unable to remap registers\n");
+		return PTR_ERR(priv->io_base);
+	}
+
+	return fpga_mgr_register(kdev, "TS-73xx FPGA Manager",
+				 &ts73xx_fpga_ops, priv);
+}
+
+static int ts73xx_fpga_remove(struct platform_device *pdev)
+{
+	fpga_mgr_unregister(&pdev->dev);
+
+	return 0;
+}
+
+static struct platform_driver ts73xx_fpga_driver = {
+	.driver	= {
+		.name	= "ts73xx-fpga-mgr",
+	},
+	.probe	= ts73xx_fpga_probe,
+	.remove	= ts73xx_fpga_remove,
+};
+module_platform_driver(ts73xx_fpga_driver);
+
+MODULE_AUTHOR("Florian Fainelli <[e-mail]>");
+MODULE_DESCRIPTION("TS-73xx FPGA Manager driver");
+MODULE_LICENSE("GPL v2");