Date:   Fri, 16 Mar 2018 09:26:54 -0700
From:   Moritz Fischer <mdf@...nel.org>
To:     Paolo Pisati <p.pisati@...il.com>
Cc:     Alan Tull <atull@...nel.org>, Moritz Fischer <mdf@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-fpga@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] fpga: lattice machxo2: Add Lattice MachXO2 support

On Fri, Mar 16, 2018 at 04:54:29PM +0100, Paolo Pisati wrote:
> 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@...il.com>
> ---
>  drivers/fpga/Kconfig       |   8 +
>  drivers/fpga/Makefile      |   1 +
>  drivers/fpga/machxo2-spi.c | 410 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 419 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.
> +
> +
>  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..3c7fc3e
> --- /dev/null
> +++ b/drivers/fpga/machxo2-spi.c
> @@ -0,0 +1,410 @@
> +/**
> + * Lattice MachXO2 Slave SPI Driver
> + *
> + * Copyright (C) 2018 Paolo Pisati <p.pisati@...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.
SPDX please.
> + *
> + * Manage Lattice FPGA firmware that is loaded over SPI using
> + * the slave serial configuration interface.

> + */
> +
> +#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>
> +
> +//#define MACHXO2_DEBUG
?! No ;-)
> +
> +/* 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 */
> +#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;
> +	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);
> +	return 0;
> +}
> +
> +#ifdef MACHXO2_DEBUG
Not a fan of this ...
> +static void dump_status_reg(unsigned long *status)
> +{
> +	char *ferr;
> +
> +	switch (get_err(status)) {
> +	case ENOERR:
> +		ferr = "No Error";
> +		break;
> +	case EID:
> +		ferr = "ID ERR";
> +		break;
> +	case ECMD:
> +		ferr = "CMD ERR";
> +		break;
> +	case ECRC:
> +		ferr = "CRC ERR";
> +		break;
> +	case EPREAM:
> +		ferr = "Preamble ERR";
> +		break;
> +	case EABRT:
> +		ferr = "Abort ERR";
> +		break;
> +	case EOVERFL:
> +		ferr = "Overflow ERR";
> +		break;
> +	case ESDMEOF:
> +		ferr = "SDM EOF";
> +		break;
> +	default:
> +		ferr = "Default switch case";
> +	}
> +	printk(KERN_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), ferr);
Not sure we need this function in the first place, if you really think
you need it at least use pr_dbg() or pr_err() here.
> +}
> +#else
> +static void dump_status_reg(unsigned long *status) {}
> +#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)
> +			break;
> +		if (++loop >= MACHXO2_MAX_BUSY_LOOP) {
> +			ret = -EBUSY;
> +			break;
> +		}
> +	} while (test_bit(BUSY, &status));
> +
> +	return ret;
> +}
> +
> +static int machxo2_cleanup(struct fpga_manager *mgr)
> +{
> +	struct spi_device *spi = mgr->priv;
> +	struct spi_message msg;
> +	struct spi_transfer tx[2];
> +	u8 erase[] = ISC_ERASE;
> +	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;
> +}

To understand this correctly: Further up you have a way to determine the
state you're in, but then you only use that for debug printout, while
here where you should provide the status you say FPGA_MGR_STATE_UNKNOWN?

Am I missing something here?
> +
> +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];
> +	u8 enable[] = ISC_ENABLE;
> +	u8 erase[] = ISC_ERASE;
> +	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;
> +	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];
> +	u8 progdone[] = ISC_PROGRAMDONE;
> +	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;
> +		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@...il.com>");
> +MODULE_DESCRIPTION("Load Lattice FPGA firmware over SPI");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.7.4
> 

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