Re: [PATCH v3 2/2] FPGA: Add TS-7300 FPGA manager

From: Moritz Fischer
Date: Wed Dec 14 2016 - 01:07:57 EST


Hi Florian,

On Tue, Dec 13, 2016 at 6:35 PM, Florian Fainelli <f.fainelli@xxxxxxxxx> wrote:
> 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 <f.fainelli@xxxxxxxxx>
> ---
> drivers/fpga/Kconfig | 7 ++
> drivers/fpga/Makefile | 1 +
> drivers/fpga/ts73xx-fpga.c | 163 +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 171 insertions(+)
> create mode 100644 drivers/fpga/ts73xx-fpga.c
>
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index ce861a2853a4..d9cbef60db80 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -33,6 +33,13 @@ config FPGA_MGR_SOCFPGA_A10
> 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
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> index 8df07bcf42a6..a1160169e6d9 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_FPGA) += fpga-mgr.o
> # FPGA Manager Drivers
> obj-$(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
> diff --git a/drivers/fpga/ts73xx-fpga.c b/drivers/fpga/ts73xx-fpga.c
> new file mode 100644
> index 000000000000..38d78d8c6b1e
> --- /dev/null
> +++ b/drivers/fpga/ts73xx-fpga.c
> @@ -0,0 +1,163 @@
> +/*
> + * Technologic Systems TS-73xx SBC FPGA loader
> + *
> + * Copyright (C) 2016 Florian Fainelli <f.fainelli@xxxxxxxxx>
> + *
> + * 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++;
> + }
> +

<snip>
> + 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);

</snip>

Just to clarify is this block what triggers the actual write? I'm asking because
I'm wondering if in the current implementation the ts73xx_fpga_write() function
can be called multiple times in your implementation before you finally get to
the write complete callback.

> +
> + reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
> + reg &= ~TS73XX_FPGA_CONFIG_LOAD;
> + writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +
> + 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;
> +
> + 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;
> + int err;
> +
> + 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);
> + }
> +
> + err = fpga_mgr_register(kdev, "TS-73xx FPGA Manager",
> + &ts73xx_fpga_ops, priv);
> + if (err) {
> + dev_err(kdev, "failed to register FPGA manager\n");
> + return err;
> + }
> +
> + return err;
> +}
> +
> +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 <f.fainelli@xxxxxxxxx>");
> +MODULE_DESCRIPTION("TS-73xx FPGA Manager driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.9.3
>

Thanks,
Moritz