Message-ID: <CANk1AXRm3NxWz_RNL60svx6WMo3722-NhV4iC4ufWcF+83VTpg@mail.gmail.com>
Date:   Mon, 5 Jun 2017 10:11:57 -0500
From:   Alan Tull <atull@...nel.org>
To:     Joshua Clayton <stillcompiling@...il.com>
Cc:     Moritz Fischer <moritz.fischer@...us.com>,
        Anatolij Gustschin <agust@...x.de>,
        Bastian Stender <bst@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Sascha Hauer <kernel@...gutronix.de>,
        Fabio Estevam <fabio.estevam@....com>,
        Russell King <linux@...linux.org.uk>,
        linux-fpga@...r.kernel.org,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v12 3/6] fpga manager: Add altera-ps-spi driver for Altera FPGAs

On Fri, Jun 2, 2017 at 3:30 PM, Joshua Clayton <stillcompiling@...il.com> wrote:
> altera-ps-spi loads FPGA firmware over SPI, using the "passive serial"
> interface on Altera Arria 10, Cyclone V or Stratix V FPGAs.
>
> This is one of the simpler ways to set up an FPGA at runtime.
> The signal interface is close to unidirectional SPI with lsb first.
>
> Signed-off-by: Joshua Clayton <stillcompiling@...il.com>
> Signed-off-by: Anatolij Gustschin <agust@...x.de>

Signed-off-by: Alan Tull <atull@...nel.org>

> ---
>  drivers/fpga/Kconfig         |   7 +
>  drivers/fpga/Makefile        |   1 +
>  drivers/fpga/altera-ps-spi.c | 297 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 305 insertions(+)
>  create mode 100644 drivers/fpga/altera-ps-spi.c
>
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index 161ba9dccede..00e4cae7b79e 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -26,6 +26,13 @@ config FPGA_MGR_ICE40_SPI
>         help
>           FPGA manager driver support for Lattice iCE40 FPGAs over SPI.
>
> +config FPGA_MGR_ALTERA_PS_SPI
> +       tristate "Altera FPGA Passive Serial over SPI"
> +       depends on SPI || COMPILE_TEST
> +       help
> +         FPGA manager driver support for Altera Arria/Cyclone/Stratix
> +         using the passive serial interface 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 2a4f0218145c..e75d3570e26a 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_ALTERA_PS_SPI)   += altera-ps-spi.o
>  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
> diff --git a/drivers/fpga/altera-ps-spi.c b/drivers/fpga/altera-ps-spi.c
> new file mode 100644
> index 000000000000..0db8def668ed
> --- /dev/null
> +++ b/drivers/fpga/altera-ps-spi.c
> @@ -0,0 +1,297 @@
> +/*
> + * Altera Passive Serial SPI Driver
> + *
> + *  Copyright (c) 2017 United Western Technologies, Corporation
> + *
> + *  Joshua Clayton <stillcompiling@...il.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * Manage Altera FPGA firmware that is loaded over SPI using the passive
> + * serial configuration method.
> + * Firmware must be in binary "rbf" format.
> + * Works on Arria 10, Cyclone V and Stratix V. Should work on Cyclone series.
> + * May work on other Altera FPGAs.
> + */
> +
> +#include <linux/bitrev.h>
> +#include <linux/delay.h>
> +#include <linux/fpga/fpga-mgr.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/of_device.h>
> +#include <linux/spi/spi.h>
> +#include <linux/sizes.h>
> +
> +enum altera_ps_devtype {
> +       CYCLONE5,
> +       ARRIA10,
> +};
> +
> +struct altera_ps_data {
> +       enum altera_ps_devtype devtype;
> +       int status_wait_min_us;
> +       int status_wait_max_us;
> +       int t_cfg_us;
> +       int t_st2ck_us;
> +};
> +
> +struct altera_ps_conf {
> +       struct gpio_desc *config;
> +       struct gpio_desc *confd;
> +       struct gpio_desc *status;
> +       struct spi_device *spi;
> +       const struct altera_ps_data *data;
> +       u32 info_flags;
> +       char mgr_name[64];
> +};
> +
> +/*          |   Arria 10  |   Cyclone5  |   Stratix5  |
> + * t_CF2ST0 |     [; 600] |     [; 600] |     [; 600] |ns
> + * t_CFG    |        [2;] |        [2;] |        [2;] |µs
> + * t_STATUS | [268; 3000] | [268; 1506] | [268; 1506] |µs
> + * t_CF2ST1 |    [; 3000] |    [; 1506] |    [; 1506] |µs
> + * t_CF2CK  |     [3010;] |     [1506;] |     [1506;] |µs
> + * t_ST2CK  |       [10;] |        [2;] |        [2;] |µs
> + * t_CD2UM  |  [175; 830] |  [175; 437] |  [175; 437] |µs
> + */
> +static struct altera_ps_data c5_data = {
> +       /* these values for Cyclone5 are compatible with Stratix5 */
> +       .devtype = CYCLONE5,
> +       .status_wait_min_us = 268,
> +       .status_wait_max_us = 1506,
> +       .t_cfg_us = 2,
> +       .t_st2ck_us = 2,
> +};
> +
> +static struct altera_ps_data a10_data = {
> +       .devtype = ARRIA10,
> +       .status_wait_min_us = 268,  /* min(t_STATUS) */
> +       .status_wait_max_us = 3000, /* max(t_CF2ST1) */
> +       .t_cfg_us = 2,    /* max { min(t_CFG), max(tCF2ST0) } */
> +       .t_st2ck_us = 10, /* min(t_ST2CK) */
> +};
> +
> +static const struct of_device_id of_ef_match[] = {
> +       { .compatible = "altr,fpga-passive-serial", .data = &c5_data },
> +       { .compatible = "altr,fpga-arria10-passive-serial", .data = &a10_data },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, of_ef_match);
> +
> +static enum fpga_mgr_states altera_ps_state(struct fpga_manager *mgr)
> +{
> +       struct altera_ps_conf *conf = mgr->priv;
> +
> +       if (gpiod_get_value_cansleep(conf->status))
> +               return FPGA_MGR_STATE_RESET;
> +
> +       return FPGA_MGR_STATE_UNKNOWN;
> +}
> +
> +static inline void altera_ps_delay(int delay_us)
> +{
> +       if (delay_us > 10)
> +               usleep_range(delay_us, delay_us + 5);
> +       else
> +               udelay(delay_us);
> +}
> +
> +static int altera_ps_write_init(struct fpga_manager *mgr,
> +                               struct fpga_image_info *info,
> +                               const char *buf, size_t count)
> +{
> +       struct altera_ps_conf *conf = mgr->priv;
> +       int min, max, waits;
> +       int i;
> +
> +       conf->info_flags = info->flags;
> +
> +       if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
> +               dev_err(&mgr->dev, "Partial reconfiguration not supported.\n");
> +               return -EINVAL;
> +       }
> +
> +       gpiod_set_value_cansleep(conf->config, 1);
> +
> +       /* wait min reset pulse time */
> +       altera_ps_delay(conf->data->t_cfg_us);
> +
> +       if (!gpiod_get_value_cansleep(conf->status)) {
> +               dev_err(&mgr->dev, "Status pin failed to show a reset\n");
> +               return -EIO;
> +       }
> +
> +       gpiod_set_value_cansleep(conf->config, 0);
> +
> +       min = conf->data->status_wait_min_us;
> +       max = conf->data->status_wait_max_us;
> +       waits = max / min;
> +       if (max % min)
> +               waits++;
> +
> +       /* wait for max { max(t_STATUS), max(t_CF2ST1) } */
> +       for (i = 0; i < waits; i++) {
> +               usleep_range(min, min + 10);
> +               if (!gpiod_get_value_cansleep(conf->status)) {
> +                       /* wait for min(t_ST2CK)*/
> +                       altera_ps_delay(conf->data->t_st2ck_us);
> +                       return 0;
> +               }
> +       }
> +
> +       dev_err(&mgr->dev, "Status pin not ready.\n");
> +       return -EIO;
> +}
> +
> +static void rev_buf(char *buf, size_t len)
> +{
> +       const char *fw_end = (buf + len);
> +
> +       /* set buffer to lsb first */
> +       while (buf < fw_end) {
> +               *buf = bitrev8(*buf);
> +               buf++;
> +       }
> +}
> +
> +static int altera_ps_write(struct fpga_manager *mgr, const char *buf,
> +                          size_t count)
> +{
> +       struct altera_ps_conf *conf = mgr->priv;
> +       const char *fw_data = buf;
> +       const char *fw_data_end = fw_data + count;
> +
> +       while (fw_data < fw_data_end) {
> +               int ret;
> +               size_t stride = min_t(size_t, fw_data_end - fw_data, SZ_4K);
> +
> +               if (!(conf->info_flags & FPGA_MGR_BITSTREAM_LSB_FIRST))
> +                       rev_buf((char *)fw_data, stride);
> +
> +               ret = spi_write(conf->spi, fw_data, stride);
> +               if (ret) {
> +                       dev_err(&mgr->dev, "spi error in firmware write: %d\n",
> +                               ret);
> +                       return ret;
> +               }
> +               fw_data += stride;
> +       }
> +
> +       return 0;
> +}
> +
> +static int altera_ps_write_complete(struct fpga_manager *mgr,
> +                                   struct fpga_image_info *info)
> +{
> +       struct altera_ps_conf *conf = mgr->priv;
> +       const char dummy[] = {0};
> +       int ret;
> +
> +       if (gpiod_get_value_cansleep(conf->status)) {
> +               dev_err(&mgr->dev, "Error during configuration.\n");
> +               return -EIO;
> +       }
> +
> +       if (!IS_ERR(conf->confd)) {
> +               if (!gpiod_get_raw_value_cansleep(conf->confd)) {
> +                       dev_err(&mgr->dev, "CONF_DONE is inactive!\n");
> +                       return -EIO;
> +               }
> +       }
> +
> +       /*
> +        * After CONF_DONE goes high, send two additional falling edges on DCLK
> +        * to begin initialization and enter user mode
> +        */
> +       ret = spi_write(conf->spi, dummy, 1);
> +       if (ret) {
> +               dev_err(&mgr->dev, "spi error during end sequence: %d\n", ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct fpga_manager_ops altera_ps_ops = {
> +       .state = altera_ps_state,
> +       .write_init = altera_ps_write_init,
> +       .write = altera_ps_write,
> +       .write_complete = altera_ps_write_complete,
> +};
> +
> +static int altera_ps_probe(struct spi_device *spi)
> +{
> +       struct altera_ps_conf *conf;
> +       const struct of_device_id *of_id;
> +
> +       conf = devm_kzalloc(&spi->dev, sizeof(*conf), GFP_KERNEL);
> +       if (!conf)
> +               return -ENOMEM;
> +
> +       of_id = of_match_device(of_ef_match, &spi->dev);
> +       if (!of_id)
> +               return -ENODEV;
> +
> +       conf->data = of_id->data;
> +       conf->spi = spi;
> +       conf->config = devm_gpiod_get(&spi->dev, "nconfig", GPIOD_OUT_HIGH);
> +       if (IS_ERR(conf->config)) {
> +               dev_err(&spi->dev, "Failed to get config gpio: %ld\n",
> +                       PTR_ERR(conf->config));
> +               return PTR_ERR(conf->config);
> +       }
> +
> +       conf->status = devm_gpiod_get(&spi->dev, "nstat", GPIOD_IN);
> +       if (IS_ERR(conf->status)) {
> +               dev_err(&spi->dev, "Failed to get status gpio: %ld\n",
> +                       PTR_ERR(conf->status));
> +               return PTR_ERR(conf->status);
> +       }
> +
> +       conf->confd = devm_gpiod_get(&spi->dev, "confd", GPIOD_IN);
> +       if (IS_ERR(conf->confd)) {
> +               dev_warn(&spi->dev, "Not using confd gpio: %ld\n",
> +                        PTR_ERR(conf->confd));
> +       }
> +
> +       /* Register manager with unique name */
> +       snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s %s",
> +                dev_driver_string(&spi->dev), dev_name(&spi->dev));
> +
> +       return fpga_mgr_register(&spi->dev, conf->mgr_name,
> +                                &altera_ps_ops, conf);
> +}
> +
> +static int altera_ps_remove(struct spi_device *spi)
> +{
> +       fpga_mgr_unregister(&spi->dev);
> +
> +       return 0;
> +}
> +
> +static const struct spi_device_id altera_ps_spi_ids[] = {
> +       {"cyclone-ps-spi", 0},
> +       {}
> +};
> +MODULE_DEVICE_TABLE(spi, altera_ps_spi_ids);
> +
> +static struct spi_driver altera_ps_driver = {
> +       .driver = {
> +               .name = "altera-ps-spi",
> +               .owner = THIS_MODULE,
> +               .of_match_table = of_match_ptr(of_ef_match),
> +       },
> +       .id_table = altera_ps_spi_ids,
> +       .probe = altera_ps_probe,
> +       .remove = altera_ps_remove,
> +};
> +
> +module_spi_driver(altera_ps_driver)
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_AUTHOR("Joshua Clayton <stillcompiling@...il.com>");
> +MODULE_DESCRIPTION("Module to load Altera FPGA firmware over SPI");
> --
> 2.11.0
>

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