On 2022-08-25 at 16:13:43 +0200, Johannes Zink wrote:
> From: Peter Jensen <pdj@xxxxxxxxxxxxxxx>
>
> The configuration flash of the machxo2 fpga can also be erased and
> written over i2c instead of spi. Add this functionality to the
> refactored common driver. Since some commands are shorter over I2C than
> they are over SPI some quirks are added to the common driver in order to
> account for that.
>
> Signed-off-by: Peter Jensen <pdj@xxxxxxxxxxxxxxx>
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
> Signed-off-by: Johannes Zink <j.zink@xxxxxxxxxxxxxx>
> ---
> drivers/fpga/Kconfig | 8 ++
> drivers/fpga/Makefile | 1 +
> drivers/fpga/machxo2-common.c | 15 +++-
> drivers/fpga/machxo2-common.h | 3 +
> drivers/fpga/machxo2-i2c.c | 137 ++++++++++++++++++++++++++++++++++
> 5 files changed, 163 insertions(+), 1 deletion(-)
> create mode 100644 drivers/fpga/machxo2-i2c.c
>
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index e5869a732246..97081bbd7c19 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -90,6 +90,14 @@ config FPGA_MGR_MACHXO2_SPI
> FPGA manager driver support for Lattice MachXO2 configuration
> over slave SPI interface.
>
> +config FPGA_MGR_MACHXO2_I2C
> + tristate "Lattice MachXO2 I2C"
> + depends on I2C
> + select FPGA_MGR_MACHXO2_COMMON
> + help
> + FPGA manager driver support for Lattice MachXO2 configuration
> + over slave I2C interface.
> +
> config FPGA_MGR_TS73XX
> tristate "Technologic Systems TS-73xx SBC FPGA Manager"
> depends on ARCH_EP93XX && MACH_TS72XX
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> index f247a8de83ad..fcdf79f4d424 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_FPGA_MGR_ALTERA_PS_SPI) += altera-ps-spi.o
> obj-$(CONFIG_FPGA_MGR_ICE40_SPI) += ice40-spi.o
> obj-$(CONFIG_FPGA_MGR_MACHXO2_COMMON) += machxo2-common.o
> obj-$(CONFIG_FPGA_MGR_MACHXO2_SPI) += machxo2-spi.o
> +obj-$(CONFIG_FPGA_MGR_MACHXO2_I2C) += machxo2-i2c.o
> obj-$(CONFIG_FPGA_MGR_SOCFPGA) += socfpga.o
> obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10) += socfpga-a10.o
> obj-$(CONFIG_FPGA_MGR_STRATIX10_SOC) += stratix10-soc.o
> diff --git a/drivers/fpga/machxo2-common.c b/drivers/fpga/machxo2-common.c
> index e8967cdee2c6..0a3c126675da 100644
> --- a/drivers/fpga/machxo2-common.c
> +++ b/drivers/fpga/machxo2-common.c
> @@ -100,7 +100,7 @@ static void dump_status_reg(struct device *dev, u32 status)
> !!FIELD_GET(MACHXO2_DVER, status), get_err_string(get_err(status)));
> }
>
> -static int machxo2_wait_until_not_busy(struct machxo2_common_priv *priv)
> +int machxo2_wait_until_not_busy(struct machxo2_common_priv *priv)
> {
> u32 status;
> int ret, loop = 0;
> @@ -143,6 +143,11 @@ static int machxo2_cleanup(struct fpga_manager *mgr)
> cmd.cmd = refresh;
> cmd.cmd_len = sizeof(refresh);
> cmd.delay_us = MACHXO2_REFRESH_USEC;
> +
> + /* quirk: refresh command over i2c is 1 byte shorter */
> + if (priv->refresh_3b)
> + cmd.cmd_len--;
> +
> ret = priv->write_commands(priv, &cmd, 1);
> if (ret)
> goto fail;
> @@ -207,6 +212,10 @@ static int machxo2_write_init(struct fpga_manager *mgr,
> cmd[0].cmd_len = sizeof(enable);
> cmd[0].delay_us = MACHXO2_LOW_DELAY_USEC;
>
> + /* quirk: enable command over i2c is 1 byte shorter */
> + if (priv->enable_3b)
> + cmd[0].cmd_len--;
> +
> cmd[1].cmd = (u8 *)&priv->erase_cmd;
> cmd[1].cmd_len = sizeof(priv->erase_cmd);
>
> @@ -313,6 +322,10 @@ static int machxo2_write_complete(struct fpga_manager *mgr,
> cmd.cmd_len = sizeof(refresh);
> cmd.delay_us = MACHXO2_REFRESH_USEC;
>
> + /* quirk: refresh command over i2c is 1 byte shorter */
> + if (priv->refresh_3b)
> + cmd.cmd_len--;
> +
> do {
> ret = priv->write_commands(priv, &cmd, 1);
> if (ret)
> diff --git a/drivers/fpga/machxo2-common.h b/drivers/fpga/machxo2-common.h
> index 0f9f53b48152..8c09345adee5 100644
> --- a/drivers/fpga/machxo2-common.h
> +++ b/drivers/fpga/machxo2-common.h
> @@ -32,9 +32,12 @@ struct machxo2_common_priv {
> int (*get_status)(struct machxo2_common_priv *priv, u32 *status);
> struct device *dev;
> __be32 erase_cmd;
> + u8 enable_3b:1;
> + u8 refresh_3b:1;
> struct gpio_desc *fpga_program_n;
> };
>
> int machxo2_common_init(struct machxo2_common_priv *priv, struct device *dev);
> +int machxo2_wait_until_not_busy(struct machxo2_common_priv *priv);
>
> #endif
> diff --git a/drivers/fpga/machxo2-i2c.c b/drivers/fpga/machxo2-i2c.c
> new file mode 100644
> index 000000000000..a309016def1c
> --- /dev/null
> +++ b/drivers/fpga/machxo2-i2c.c
> @@ -0,0 +1,137 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Lattice MachXO2 Slave I2C Driver
> + *
> + * Manage Lattice FPGA firmware that is loaded over I2C using
> + * the slave serial configuration interface.
> + *
> + * Copyright (C) 2018 Paolo Pisati <p.pisati@xxxxxxxxx>
> + * Copyright (C) 2021 Peter Jensen <pdj@xxxxxxxxxxxxxxx>
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/container_of.h>
> +#include <linux/delay.h>
> +#include "machxo2-common.h"
> +
> +
> +struct machxo2_i2c_priv {
> + struct machxo2_common_priv common;
> + struct i2c_client *client;
> +};
> +
> +static inline struct machxo2_i2c_priv *to_machxo2_i2c_priv(struct machxo2_common_priv *common)
> +{
> + return container_of(common, struct machxo2_i2c_priv, common);
> +}
> +
> +static int machxo2_i2c_get_status(struct machxo2_common_priv *bus, u32 *status)
> +{
> + struct machxo2_i2c_priv *i2cPriv = to_machxo2_i2c_priv(bus);
> + struct i2c_client *client = i2cPriv->client;
> + u8 read_status[] = LSC_READ_STATUS;
The command word could also be bus agnostic. I think a callback like
write_then_read(bus, txbuf, n_tx, rxbuf, n_rx) could be a better
abstraction.
> + __be32 tmp;
> + int ret;
> + struct i2c_msg msg[] = {
> + {
> + .addr = client->addr,
> + .flags = 0,
> + .buf = read_status,
> + .len = ARRAY_SIZE(read_status),
> + }, {
> + .addr = client->addr,
> + .flags = I2C_M_RD,
> + .buf = (u8 *) &tmp,
> + .len = sizeof(tmp)
> + }
> + };
> +
> + ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
> + if (ret < 0)
> + return ret;
> + if (ret != ARRAY_SIZE(msg))
> + return -EIO;
> + *status = be32_to_cpu(tmp);
> +
> + return 0;
> +}
> +
> +static int machxo2_i2c_write(struct machxo2_common_priv *common,
> + struct machxo2_cmd *cmds, size_t cmd_count)
> +{
> + struct machxo2_i2c_priv *i2c_priv = to_machxo2_i2c_priv(common);
> + struct i2c_client *client = i2c_priv->client;
> + size_t i;
> + int ret;
> +
> + for (i = 0; i < cmd_count; i++) {
> + struct i2c_msg msg[] = {
> + {
> + .addr = client->addr,
> + .buf = cmds[i].cmd,
> + .len = cmds[i].cmd_len,
> + },
> + };
> +
> + ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
> + if (ret < 0)
> + return ret;
> + if (ret != ARRAY_SIZE(msg))
> + return -EIO;
> + if (cmds[i].delay_us)
> + usleep_range(cmds[i].delay_us, cmds[i].delay_us +
> + cmds[i].delay_us / 4);
> + if (i < cmd_count - 1) /* on any iteration except for the last one... */
> + ret = machxo2_wait_until_not_busy(common);
Seems no need to implement the loop and wait in transportation layer,
they are common. A callback like write(bus, txbuf, n_tx) is better?
Thanks,
Yilun
> + }
> +
> + return 0;
> +}
> +
> +static int machxo2_i2c_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct device *dev = &client->dev;
> + struct machxo2_i2c_priv *priv;
> +
> + priv = devm_kzalloc(dev, sizeof(struct machxo2_i2c_priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->client = client;
> + priv->common.get_status = machxo2_i2c_get_status;
> + priv->common.write_commands = machxo2_i2c_write;
> +
> + /* Commands are usually 4b, but these aren't for i2c */
> + priv->common.enable_3b = true;
> + priv->common.refresh_3b = true;
> +
> + return machxo2_common_init(&priv->common, dev);
> +}
> +
> +static const struct of_device_id of_match[] = {
> + { .compatible = "lattice,machxo2-slave-i2c", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, of_match);
> +
> +static const struct i2c_device_id lattice_ids[] = {
> + { "machxo2-slave-i2c", 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, lattice_ids);
> +
> +static struct i2c_driver machxo2_i2c_driver = {
> + .driver = {
> + .name = "machxo2-slave-i2c",
> + .of_match_table = of_match_ptr(of_match),
> + },
> + .probe = machxo2_i2c_probe,
> + .id_table = lattice_ids,
> +};
> +
> +module_i2c_driver(machxo2_i2c_driver);
> +
> +MODULE_AUTHOR("Peter Jensen <pdj@xxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Load Lattice FPGA firmware over I2C");
> +MODULE_LICENSE("GPL");
> --
> 2.30.2
>
