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From:   Alan Tull <atull@kernel.org>
Date:   Wed, 28 Mar 2018 15:03:42 -0500
Message-ID: <CANk1AXQyZdoxXnLTtwR0fkYjgdB36XABQSwdxk6eQoQJtLC80w@mail.gmail.com>
Subject: Re: [PATCH 2/2] fpga: lattice machxo2: Add Lattice MachXO2 support
To:     Paolo Pisati <p.pisati@gmail.com>
Cc:     Moritz Fischer <mdf@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-fpga@vger.kernel.org,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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On Wed, Mar 28, 2018 at 11:26 AM, Alan Tull <atull@kernel.org> wrote:
> On Fri, Mar 23, 2018 at 7:27 AM, Paolo Pisati <p.pisati@gmail.com> wrote:
>
> Hi Paolo,

One more thing.  The api for registering a FPGA manager is changing.
It won't be hard to adapt.  I've pushed a branch that includes the
patches that add this change.  Please rebase on top of that branch so
your patch can go in on top of that.

My git repo is at:
git://git.kernel.org/pub/scm/linux/kernel/git/atull/linux-fpga.git

The branch name is
for-review-next-20180327-drvdata-v3

Alan

>
> Looking good.  A few things below.  Also, when you post, please use
> the '-v' parameter of 'git format-patch' to add the version to the
> subject line such as [PATCH v9].
>
>> This patch adds support to the FPGA manager for programming
>> MachXO2 device’s internal flash memory, via slave SPI.
>>
>> Signed-off-by: Paolo Pisati <p.pisati@gmail.com>
>> ---
>>  drivers/fpga/Kconfig       |   8 +
>>  drivers/fpga/Makefile      |   1 +
>>  drivers/fpga/machxo2-spi.c | 388 +++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 397 insertions(+)
>>  create mode 100644 drivers/fpga/machxo2-spi.c
>>
>> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
>> index ad5448f..65ccbc5 100644
>> --- a/drivers/fpga/Kconfig
>> +++ b/drivers/fpga/Kconfig
>> @@ -38,6 +38,14 @@ config FPGA_MGR_ALTERA_PS_SPI
>>           FPGA manager driver support for Altera Arria/Cyclone/Stratix
>>           using the passive serial interface over SPI.
>>
>> +config FPGA_MGR_MACHXO2_SPI
>> +       tristate "Lattice MachXO2 SPI"
>> +       depends on SPI
>> +       help
>> +         FPGA manager driver support for Lattice MachXO2 configuration
>> +         over slave SPI interface.
>> +
>> +
>
> Please move this section after FPGA_MGR_ICE40_SPI.  That keeps the two
> lattice drivers together in the Kconfig.  You may need to rebase your
> driver to go onto linux-next.
>
> Also, please delete the extra line feed above.
>
>>  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 f98dcf1..38abb08 100644
>> --- a/drivers/fpga/Makefile
>> +++ b/drivers/fpga/Makefile
>> @@ -10,6 +10,7 @@ obj-$(CONFIG_FPGA)                    += fpga-mgr.o
>>  obj-$(CONFIG_FPGA_MGR_ALTERA_CVP)      += altera-cvp.o
>>  obj-$(CONFIG_FPGA_MGR_ALTERA_PS_SPI)   += altera-ps-spi.o
>>  obj-$(CONFIG_FPGA_MGR_ICE40_SPI)       += ice40-spi.o
>> +obj-$(CONFIG_FPGA_MGR_MACHXO2_SPI)     += machxo2-spi.o
>>  obj-$(CONFIG_FPGA_MGR_SOCFPGA)         += socfpga.o
>>  obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10)     += socfpga-a10.o
>>  obj-$(CONFIG_FPGA_MGR_TS73XX)          += ts73xx-fpga.o
>> diff --git a/drivers/fpga/machxo2-spi.c b/drivers/fpga/machxo2-spi.c
>> new file mode 100644
>> index 0000000..6a5c5c7
>> --- /dev/null
>> +++ b/drivers/fpga/machxo2-spi.c
>> @@ -0,0 +1,388 @@
>> +// SPDX-License-Identifier: GPL-2.0
>
> The above line is good but...
>
>> +// Lattice MachXO2 Slave SPI Driver
>> +//
>> +// Manage Lattice FPGA firmware that is loaded over SPI using
>> +// the slave serial configuration interface.
>> +//
>> +// Copyright (C) 2018 Paolo Pisati <p.pisati@gmail.com>
>
> This stuff should be as:
> /*
>  * some stuff
>  * more stuff
>  */
>
>> +
>> +//#define DEBUG
>
> Please remove the //#define DEBUG
>
>> +
>> +#include <linux/delay.h>
>> +#include <linux/fpga/fpga-mgr.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/spi/spi.h>
>> +
>> +/* MachXO2 Programming Guide - sysCONFIG Programming Commands */
>> +#define IDCODE_PUB                     {0xe0, 0x00, 0x00, 0x00}
>> +#define ISC_ENABLE                     {0xc6, 0x08, 0x00, 0x00}
>> +#define ISC_ERASE                      {0x0e, 0x04, 0x00, 0x00}
>> +#define ISC_PROGRAMDONE                {0x5e, 0x00, 0x00, 0x00}
>> +#define LSC_INITADDRESS                {0x46, 0x00, 0x00, 0x00}
>> +#define LSC_PROGINCRNV         {0x70, 0x00, 0x00, 0x01}
>> +#define LSC_READ_STATUS                {0x3c, 0x00, 0x00, 0x00}
>> +#define LSC_REFRESH                    {0x79, 0x00, 0x00, 0x00}
>> +
>> +/*
>> + * Max CCLK in Slave SPI mode according to 'MachXO2 Family Data
>> + * Sheet' sysCONFIG Port Timing Specifications (3-36)
>> + */
>> +#define MACHXO2_MAX_SPEED                      66000000
>> +
>> +#define MACHXO2_LOW_DELAY                      5               /* us */
>
> I'd prefer MACHXO2_LOW_DELAY_USEC so that you don't need the comment
> here and it's clear in the rest of the driver.  Same for the next two.
>
>> +#define MACHXO2_HIGH_DELAY                     200             /* us */
>> +#define MACHXO2_REFRESH                                4800    /* us */
>> +#define MACHXO2_MAX_BUSY_LOOP          128
>> +#define MACHXO2_MAX_REFRESH_LOOP       16
>> +
>> +#define MACHXO2_PAGE_SIZE                      16
>> +#define MACHXO2_BUF_SIZE                       (MACHXO2_PAGE_SIZE + 4)
>> +
>> +/* Status register bits, errors and error mask */
>> +#define BUSY   12
>> +#define DONE   8
>> +#define DVER   27
>> +#define ENAB   9
>> +#define ERRBITS        23
>> +#define ERRMASK        7
>> +#define FAIL   13
>> +
>> +#define ENOERR 0 /* no error */
>> +#define EID            1
>> +#define ECMD   2
>> +#define        ECRC    3
>> +#define EPREAM 4 /* preamble error */
>> +#define EABRT  5 /* abort error */
>> +#define EOVERFL 6 /* overflow error */
>> +#define ESDMEOF 7 /* SDM EOF */
>> +
>> +static inline u8 get_err(unsigned long *status)
>> +{
>> +       return (*status >> ERRBITS) & ERRMASK;
>> +}
>> +
>> +static int get_status(struct spi_device *spi, unsigned long *status)
>> +{
>> +       struct spi_message msg;
>> +       struct spi_transfer rx, tx;
>> +       static const u8 cmd[] = LSC_READ_STATUS;
>> +       int ret;
>> +
>> +       memset(&rx, 0, sizeof(rx));
>> +       memset(&tx, 0, sizeof(tx));
>> +       tx.tx_buf = cmd;
>> +       tx.len = sizeof(cmd);
>> +       rx.rx_buf = status;
>> +       rx.len = 4;
>> +       spi_message_init(&msg);
>> +       spi_message_add_tail(&tx, &msg);
>> +       spi_message_add_tail(&rx, &msg);
>> +       ret = spi_sync(spi, &msg);
>> +       if (ret)
>> +               return ret;
>> +
>> +       *status = be32_to_cpu(*status);
>
> Add a line feed before returning.
>
>> +       return 0;
>> +}
>> +
>> +#ifdef DEBUG
>> +static const char *get_err_string(u8 err)
>> +{
>> +       switch (err) {
>> +       case ENOERR:    return "No Error";
>> +       case EID:               return "ID ERR";
>> +       case ECMD:              return "CMD ERR";
>> +       case ECRC:              return "CRC ERR";
>> +       case EPREAM:    return "Preamble ERR";
>> +       case EABRT:             return "Abort ERR";
>> +       case EOVERFL:   return "Overflow ERR";
>> +       case ESDMEOF:   return "SDM EOF";
>> +       }
>
> Line feed before returning
>
>> +       return "Default switch case";
>> +}
>> +#endif
>> +
>> +static void dump_status_reg(unsigned long *status)
>> +{
>> +#ifdef DEBUG
>> +       pr_debug("machxo2 status: 0x%08lX - done=%d, cfgena=%d, busy=%d, fail=%d, devver=%d, err=%s\n",
>> +               *status, test_bit(DONE, status), test_bit(ENAB, status),
>> +               test_bit(BUSY, status), test_bit(FAIL, status),
>> +               test_bit(DVER, status), get_err_string(get_err(status)));
>
> Please align the the 3 lines after the pr_debug to match the above parentheses.
>
>> +#endif
>> +}
>> +
>> +static int wait_until_not_busy(struct spi_device *spi)
>> +{
>> +       unsigned long status;
>> +       int ret, loop = 0;
>> +
>> +       do {
>> +               ret = get_status(spi, &status);
>> +               if (ret)
>> +                       return ret;
>> +               if (++loop >= MACHXO2_MAX_BUSY_LOOP)
>> +                       return -EBUSY;
>> +       } while (test_bit(BUSY, &status));
>> +
>> +       return 0;
>> +}
>> +
>> +static int machxo2_cleanup(struct fpga_manager *mgr)
>> +{
>> +       struct spi_device *spi = mgr->priv;
>> +       struct spi_message msg;
>> +       struct spi_transfer tx[2];
>> +       static const u8 erase[] = ISC_ERASE;
>> +       static const u8 refresh[] = LSC_REFRESH;
>> +       int ret;
>> +
>> +       memset(tx, 0, sizeof(tx));
>> +       spi_message_init(&msg);
>> +       tx[0].tx_buf = &erase;
>> +       tx[0].len = sizeof(erase);
>> +       spi_message_add_tail(&tx[0], &msg);
>> +       ret = spi_sync(spi, &msg);
>> +       if (ret)
>> +               goto fail;
>> +
>> +       ret = wait_until_not_busy(spi);
>> +       if (ret)
>> +               goto fail;
>> +
>> +       spi_message_init(&msg);
>> +       tx[1].tx_buf = &refresh;
>> +       tx[1].len = sizeof(refresh);
>> +       tx[1].delay_usecs = MACHXO2_REFRESH;
>> +       spi_message_add_tail(&tx[1], &msg);
>> +       ret = spi_sync(spi, &msg);
>> +       if (ret)
>> +               goto fail;
>> +
>> +       return 0;
>> +fail:
>> +       dev_err(&mgr->dev, "Cleanup failed\n");
>> +       return ret;
>> +}
>> +
>> +static enum fpga_mgr_states machxo2_spi_state(struct fpga_manager *mgr)
>> +{
>> +       return FPGA_MGR_STATE_UNKNOWN;
>
> If you have a way of reporting whether the FPGA is in operating state
> or some error state, etc here, that would be nice.
>
>> +}
>> +
>> +static int machxo2_write_init(struct fpga_manager *mgr,
>> +                             struct fpga_image_info *info,
>> +                             const char *buf, size_t count)
>> +{
>> +       struct spi_device *spi = mgr->priv;
>> +       struct spi_message msg;
>> +       struct spi_transfer tx[3];
>> +       static const u8 enable[] = ISC_ENABLE;
>> +       static const u8 erase[] = ISC_ERASE;
>> +       static const u8 initaddr[] = LSC_INITADDRESS;
>> +       unsigned long status;
>> +       int ret;
>> +
>> +       if ((info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
>> +               dev_err(&mgr->dev,
>> +                       "Partial reconfiguration is not supported\n");
>> +               return -ENOTSUPP;
>> +       }
>> +
>> +       get_status(spi, &status);
>> +       dump_status_reg(&status);
>> +       memset(tx, 0, sizeof(tx));
>> +       spi_message_init(&msg);
>> +       tx[0].tx_buf = &enable;
>> +       tx[0].len = sizeof(enable);
>> +       tx[0].delay_usecs = MACHXO2_LOW_DELAY;
>> +       spi_message_add_tail(&tx[0], &msg);
>> +
>> +       tx[1].tx_buf = &erase;
>> +       tx[1].len = sizeof(erase);
>> +       spi_message_add_tail(&tx[1], &msg);
>> +       ret = spi_sync(spi, &msg);
>> +       if (ret)
>> +               goto fail;
>> +
>> +       ret = wait_until_not_busy(spi);
>> +       if (ret)
>> +               goto fail;
>> +
>> +       get_status(spi, &status);
>> +       if (test_bit(FAIL, &status))
>> +               goto fail;
>> +       dump_status_reg(&status);
>> +
>> +       spi_message_init(&msg);
>> +       tx[2].tx_buf = &initaddr;
>> +       tx[2].len = sizeof(initaddr);
>> +       spi_message_add_tail(&tx[2], &msg);
>> +       ret = spi_sync(spi, &msg);
>> +       if (ret)
>> +               goto fail;
>> +
>> +       get_status(spi, &status);
>> +       dump_status_reg(&status);
>> +       return 0;
>> +fail:
>> +       dev_err(&mgr->dev, "Error during FPGA init.\n");
>> +       return ret;
>> +}
>> +
>> +static int machxo2_write(struct fpga_manager *mgr, const char *buf,
>> +                        size_t count)
>> +{
>> +       struct spi_device *spi = mgr->priv;
>> +       struct spi_message msg;
>> +       struct spi_transfer tx;
>> +       static const u8 progincr[] = LSC_PROGINCRNV;
>> +       u8 payload[MACHXO2_BUF_SIZE];
>> +       unsigned long status;
>> +       int i, ret;
>> +
>> +       if (count % MACHXO2_PAGE_SIZE != 0) {
>> +               dev_err(&mgr->dev, "Malformed payload.\n");
>> +               return -EINVAL;
>> +       }
>> +       get_status(spi, &status);
>> +       dump_status_reg(&status);
>> +       memcpy(payload, &progincr, sizeof(progincr));
>> +       for (i = 0; i < count; i += MACHXO2_PAGE_SIZE) {
>> +               memcpy(&payload[sizeof(progincr)], &buf[i], MACHXO2_PAGE_SIZE);
>> +               memset(&tx, 0, sizeof(tx));
>> +               spi_message_init(&msg);
>> +               tx.tx_buf = payload;
>> +               tx.len = MACHXO2_BUF_SIZE;
>> +               tx.delay_usecs = MACHXO2_HIGH_DELAY;
>> +               spi_message_add_tail(&tx, &msg);
>> +               ret = spi_sync(spi, &msg);
>> +               if (ret) {
>> +                       dev_err(&mgr->dev, "Error loading the bitstream.\n");
>> +                       return ret;
>> +               }
>> +       }
>> +       get_status(spi, &status);
>> +       dump_status_reg(&status);
>> +
>> +       return 0;
>> +}
>> +
>> +static int machxo2_write_complete(struct fpga_manager *mgr,
>> +                                 struct fpga_image_info *info)
>> +{
>> +       struct spi_device *spi = mgr->priv;
>> +       struct spi_message msg;
>> +       struct spi_transfer tx[2];
>> +       static const u8 progdone[] = ISC_PROGRAMDONE;
>> +       static const u8 refresh[] = LSC_REFRESH;
>> +       unsigned long status;
>> +       int ret, refreshloop = 0;
>> +
>> +       memset(tx, 0, sizeof(tx));
>> +       spi_message_init(&msg);
>> +       tx[0].tx_buf = &progdone;
>> +       tx[0].len = sizeof(progdone);
>> +       spi_message_add_tail(&tx[0], &msg);
>> +       ret = spi_sync(spi, &msg);
>> +       if (ret)
>> +               goto fail;
>> +       ret = wait_until_not_busy(spi);
>> +       if (ret)
>> +               goto fail;
>> +
>> +       get_status(spi, &status);
>> +       dump_status_reg(&status);
>> +       if (!test_bit(DONE, &status)) {
>> +               machxo2_cleanup(mgr);
>> +               goto fail;
>> +       }
>> +
>> +       do {
>> +               spi_message_init(&msg);
>> +               tx[1].tx_buf = &refresh;
>> +               tx[1].len = sizeof(refresh);
>> +               tx[1].delay_usecs = MACHXO2_REFRESH;
>> +               spi_message_add_tail(&tx[1], &msg);
>> +               ret = spi_sync(spi, &msg);
>> +               if (ret)
>> +                       goto fail;
>> +
>> +               /* check refresh status */
>> +               get_status(spi, &status);
>> +               dump_status_reg(&status);
>> +               if (!test_bit(BUSY, &status) && test_bit(DONE, &status) &&
>> +                       get_err(&status) == ENOERR)
>> +                               break;
>
> The get_err should be aligned with the above parentheses.  Then you
> can adjust the indentation of the break.
>
>> +               if (++refreshloop == MACHXO2_MAX_REFRESH_LOOP) {
>> +                       machxo2_cleanup(mgr);
>> +                       goto fail;
>> +               }
>> +       } while (1);
>> +
>> +       get_status(spi, &status);
>> +       dump_status_reg(&status);
>> +       return 0;
>> +fail:
>> +       dev_err(&mgr->dev, "Refresh failed.\n");
>> +       return ret;
>> +}
>> +
>> +static const struct fpga_manager_ops machxo2_ops = {
>> +       .state = machxo2_spi_state,
>> +       .write_init = machxo2_write_init,
>> +       .write = machxo2_write,
>> +       .write_complete = machxo2_write_complete,
>> +};
>> +
>> +static int machxo2_spi_probe(struct spi_device *spi)
>> +{
>> +       struct device *dev = &spi->dev;
>> +
>> +       if (spi->max_speed_hz > MACHXO2_MAX_SPEED) {
>> +               dev_err(dev, "Speed is too high\n");
>> +               return -EINVAL;
>> +       }
>> +
>> +       return fpga_mgr_register(dev, "Lattice MachXO2 SPI FPGA Manager",
>> +                                &machxo2_ops, spi);
>> +}
>> +
>> +static int machxo2_spi_remove(struct spi_device *spi)
>> +{
>> +       struct device *dev = &spi->dev;
>> +
>> +       fpga_mgr_unregister(dev);
>> +
>> +       return 0;
>> +}
>> +
>> +static const struct of_device_id of_match[] = {
>> +       { .compatible = "lattice,machxo2-slave-spi", },
>> +       {}
>> +};
>> +MODULE_DEVICE_TABLE(of, of_match);
>> +
>> +static const struct spi_device_id lattice_ids[] = {
>> +       { "machxo2-slave-spi", 0 },
>> +       { },
>> +};
>> +MODULE_DEVICE_TABLE(spi, lattice_ids);
>> +
>> +static struct spi_driver machxo2_spi_driver = {
>> +       .driver = {
>> +               .name = "machxo2-slave-spi",
>> +               .of_match_table = of_match_ptr(of_match),
>> +       },
>> +       .probe = machxo2_spi_probe,
>> +       .remove = machxo2_spi_remove,
>> +       .id_table = lattice_ids,
>> +};
>> +
>> +module_spi_driver(machxo2_spi_driver)
>> +
>> +MODULE_AUTHOR("Paolo Pisati <p.pisati@gmail.com>");
>> +MODULE_DESCRIPTION("Load Lattice FPGA firmware over SPI");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 2.7.4
>>