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

[Moritz Fischer]

Hi Florian,

can you Cc: linxu-fpga@xxxxxxxxxxxxxxx for your next round?

On Sun, Dec 11, 2016 at 2:17 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.
>
> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> ---
>  drivers/fpga/Kconfig       |   7 ++
>  drivers/fpga/Makefile      |   1 +
>  drivers/fpga/ts73xx-fpga.c | 165 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 173 insertions(+)
>  create mode 100644 drivers/fpga/ts73xx-fpga.c
>
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index cd84934774cc..109625707ef0 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -26,6 +26,13 @@ config FPGA_MGR_ZYNQ_FPGA
>         help
>           FPGA manager driver support for Xilinx Zynq FPGAs.
>
> +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.
> +
>  endif # FPGA
>
>  endmenu
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> index 8d83fc6b1613..5d51265cc1b4 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -8,3 +8,4 @@ obj-$(CONFIG_FPGA)                      += fpga-mgr.o
>  # FPGA Manager Drivers
>  obj-$(CONFIG_FPGA_MGR_SOCFPGA)         += socfpga.o
>  obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)       += zynq-fpga.o
> +obj-$(CONFIG_FPGA_MGR_TS73XX)          += ts73xx-fpga.o
> diff --git a/drivers/fpga/ts73xx-fpga.c b/drivers/fpga/ts73xx-fpga.c
> new file mode 100644
> index 000000000000..2b3d5d668dfc
> --- /dev/null
> +++ b/drivers/fpga/ts73xx-fpga.c
> @@ -0,0 +1,165 @@
> +/*
> + * 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/bitrev.h>
> +#include <linux/fpga/fpga-mgr.h>
> +
> +#define TS73XX_FPGA_DATA_REG   0
> +#define TS73XX_FPGA_CONFIG_REG 1
> +
> +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, u32 flags,
> +                                 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(30);
> +       writeb(0x2, priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +       udelay(80);
> +
> +       return 0;
> +}
> +
> +static inline int ts73xx_fpga_can_write(struct ts73xx_fpga_priv *priv)
> +{
> +       unsigned int timeout = 1000;
> +       u8 reg;
> +
> +       while (timeout--) {
> +               reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +               if (!(reg & 0x1))
> +                       return 0;
> +               cpu_relax();
> +       }

You can use readb_poll_timeout() for this I think.
> +
> +       return -ETIMEDOUT;
> +}
> +
> +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 = ts73xx_fpga_can_write(priv);
> +               if (ret < 0)
> +                       return ret;
> +
> +               writeb(buf[i], priv->io_base + TS73XX_FPGA_DATA_REG);
> +               i++;
> +       }
> +
> +       usleep_range(1000, 2000);
> +       reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +       reg |= 0x8;

What's happening here?

> +       writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +       usleep_range(1000, 2000);
> +
> +       reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +       reg &= ~0x8;

and here? Can we have a named constant for these, or a comment to
explain what happens?
> +       writeb(reg, priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +
> +       return 0;
> +}
> +
> +static int ts73xx_fpga_write_complete(struct fpga_manager *mgr, u32 flags)
> +{
> +       struct ts73xx_fpga_priv *priv = mgr->priv;
> +       u8 reg;
> +
> +       reg = readb(priv->io_base + TS73XX_FPGA_CONFIG_REG);
> +       if ((reg & 0x4) != 0x4)

Named constants, please

> +               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 fpga_manager *mgr;
> +       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))
> +               return PTR_ERR(priv->io_base);

Maybe an error message here?
> +
> +       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