Re: [PATCH v4 1/3] fpga: xilinx-spi: extract a common driver core
From: Charles Perry
Date: Sun Mar 03 2024 - 12:30:28 EST
On Feb 26, 2024, at 2:19 AM, Xu Yilun yilun.xu@xxxxxxxxxxxxxxx wrote:
> On Wed, Feb 21, 2024 at 02:50:47PM -0500, Charles Perry wrote:
>> Factor out the gpio handshaking (using PROGRAM_B, INIT_B and DONE)
>> protocol in xilinx-core so that it can be reused for another driver.
>> This commit does not change anything functionally to xilinx-spi.
>>
>> xilinx-core expects drivers to provide a single operation:
>>
>> * ->write(const char* buf, size_t count): write to the device
>>
>> As well as a struct device* for resource management.
>>
>> Signed-off-by: Charles Perry <charles.perry@xxxxxxxxxxxxxxxxxxxx>
>> ---
>> drivers/fpga/Kconfig | 4 +
>> drivers/fpga/Makefile | 1 +
>> drivers/fpga/xilinx-core.c | 208 ++++++++++++++++++++++++++++++++++++
>> drivers/fpga/xilinx-core.h | 28 +++++
>> drivers/fpga/xilinx-spi.c | 212 +++----------------------------------
>> 5 files changed, 254 insertions(+), 199 deletions(-)
>> create mode 100644 drivers/fpga/xilinx-core.c
>> create mode 100644 drivers/fpga/xilinx-core.h
>>
>> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
>> index 2f689ac4ba3a3..d27a1ebf40838 100644
>> --- a/drivers/fpga/Kconfig
>> +++ b/drivers/fpga/Kconfig
>> @@ -64,9 +64,13 @@ config FPGA_MGR_STRATIX10_SOC
>> help
>> FPGA manager driver support for the Intel Stratix10 SoC.
>>
>> +config FPGA_MGR_XILINX_CORE
>> + tristate
>> +
>> config FPGA_MGR_XILINX_SPI
>> tristate "Xilinx Configuration over Slave Serial (SPI)"
>> depends on SPI
>> + select FPGA_MGR_XILINX_CORE
>> help
>> FPGA manager driver support for Xilinx FPGA configuration
>> over slave serial interface.
>> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
>> index 352a2612623e0..7ec795b6a5a70 100644
>> --- a/drivers/fpga/Makefile
>> +++ b/drivers/fpga/Makefile
>> @@ -15,6 +15,7 @@ obj-$(CONFIG_FPGA_MGR_SOCFPGA) += socfpga.o
>> obj-$(CONFIG_FPGA_MGR_SOCFPGA_A10) += socfpga-a10.o
>> obj-$(CONFIG_FPGA_MGR_STRATIX10_SOC) += stratix10-soc.o
>> obj-$(CONFIG_FPGA_MGR_TS73XX) += ts73xx-fpga.o
>> +obj-$(CONFIG_FPGA_MGR_XILINX_CORE) += xilinx-core.o
>> obj-$(CONFIG_FPGA_MGR_XILINX_SPI) += xilinx-spi.o
>> obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA) += zynq-fpga.o
>> obj-$(CONFIG_FPGA_MGR_ZYNQMP_FPGA) += zynqmp-fpga.o
>> diff --git a/drivers/fpga/xilinx-core.c b/drivers/fpga/xilinx-core.c
>> new file mode 100644
>> index 0000000000000..597e8b7a530b7
>> --- /dev/null
>> +++ b/drivers/fpga/xilinx-core.c
>> @@ -0,0 +1,208 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Common parts of the Xilinx Spartan6 and 7 Series FPGA manager drivers.
>> + *
>> + * Copyright (C) 2017 DENX Software Engineering
>> + *
>> + * Anatolij Gustschin <agust@xxxxxxx>
>> + */
>> +
>> +#include "xilinx-core.h"
>> +
>> +#include <linux/delay.h>
>> +#include <linux/fpga/fpga-mgr.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/of.h>
>> +
>> +static int get_done_gpio(struct fpga_manager *mgr)
>> +{
>> + struct xilinx_fpga_core *core = mgr->priv;
>> + int ret;
>> +
>> + ret = gpiod_get_value(core->done);
>> + if (ret < 0)
>> + dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret);
>> +
>> + return ret;
>> +}
>> +
>> +static enum fpga_mgr_states xilinx_core_state(struct fpga_manager *mgr)
>> +{
>> + if (!get_done_gpio(mgr))
>> + return FPGA_MGR_STATE_RESET;
>> +
>> + return FPGA_MGR_STATE_UNKNOWN;
>> +}
>> +
>> +/**
>> + * wait_for_init_b - wait for the INIT_B pin to have a given state, or wait
>> + * a given delay if the pin is unavailable
>> + *
>> + * @mgr: The FPGA manager object
>> + * @value: Value INIT_B to wait for (1 = asserted = low)
>> + * @alt_udelay: Delay to wait if the INIT_B GPIO is not available
>> + *
>> + * Returns 0 when the INIT_B GPIO reached the given state or -ETIMEDOUT if
>> + * too much time passed waiting for that. If no INIT_B GPIO is available
>> + * then always return 0.
>> + */
>> +static int wait_for_init_b(struct fpga_manager *mgr, int value,
>> + unsigned long alt_udelay)
>> +{
>> + struct xilinx_fpga_core *core = mgr->priv;
>> + unsigned long timeout = jiffies + msecs_to_jiffies(1000);
>> +
>> + if (core->init_b) {
>> + while (time_before(jiffies, timeout)) {
>> + int ret = gpiod_get_value(core->init_b);
>> +
>> + if (ret == value)
>> + return 0;
>> +
>> + if (ret < 0) {
>> + dev_err(&mgr->dev,
>> + "Error reading INIT_B (%d)\n", ret);
>> + return ret;
>> + }
>> +
>> + usleep_range(100, 400);
>> + }
>> +
>> + dev_err(&mgr->dev, "Timeout waiting for INIT_B to %s\n",
>> + value ? "assert" : "deassert");
>> + return -ETIMEDOUT;
>> + }
>> +
>> + udelay(alt_udelay);
>> +
>> + return 0;
>> +}
>> +
>> +static int xilinx_core_write_init(struct fpga_manager *mgr,
>> + struct fpga_image_info *info, const char *buf,
>> + size_t count)
>> +{
>> + struct xilinx_fpga_core *core = mgr->priv;
>> + int err;
>> +
>> + if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
>> + dev_err(&mgr->dev, "Partial reconfiguration not supported\n");
>> + return -EINVAL;
>> + }
>> +
>> + gpiod_set_value(core->prog_b, 1);
>> +
>> + err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
>> + if (err) {
>> + gpiod_set_value(core->prog_b, 0);
>> + return err;
>> + }
>> +
>> + gpiod_set_value(core->prog_b, 0);
>> +
>> + err = wait_for_init_b(mgr, 0, 0);
>> + if (err)
>> + return err;
>> +
>> + if (get_done_gpio(mgr)) {
>> + dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
>> + return -EIO;
>> + }
>> +
>> + /* program latency */
>> + usleep_range(7500, 7600);
>> + return 0;
>> +}
>> +
>> +static int xilinx_core_write(struct fpga_manager *mgr, const char *buf,
>> + size_t count)
>> +{
>> + struct xilinx_fpga_core *core = mgr->priv;
>> +
>> + return core->write(core, buf, count);
>> +}
>> +
>> +static int xilinx_core_write_complete(struct fpga_manager *mgr,
>> + struct fpga_image_info *info)
>> +{
>> + struct xilinx_fpga_core *core = mgr->priv;
>> + unsigned long timeout =
>> + jiffies + usecs_to_jiffies(info->config_complete_timeout_us);
>> + bool expired = false;
>> + int done;
>> + int ret;
>> + const char padding[1] = { 0xff };
>> +
>> + /*
>> + * This loop is carefully written such that if the driver is
>> + * scheduled out for more than 'timeout', we still check for DONE
>> + * before giving up and we apply 8 extra CCLK cycles in all cases.
>> + */
>> + while (!expired) {
>> + expired = time_after(jiffies, timeout);
>> +
>> + done = get_done_gpio(mgr);
>> + if (done < 0)
>> + return done;
>> +
>> + ret = core->write(core, padding, 1);
> ^
>
> sizeof(padding), Use as less immediate numbers as possible.
>
Ok
>> + if (ret)
>> + return ret;
>> +
>> + if (done)
>> + return 0;
>> + }
>> +
>> + if (core->init_b) {
>> + ret = gpiod_get_value(core->init_b);
>> +
>> + if (ret < 0) {
>> + dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
>> + return ret;
>> + }
>> +
>> + dev_err(&mgr->dev,
>> + ret ? "CRC error or invalid device\n" :
>> + "Missing sync word or incomplete bitstream\n");
>> + } else {
>> + dev_err(&mgr->dev, "Timeout after config data transfer\n");
>> + }
>> +
>> + return -ETIMEDOUT;
>> +}
>> +
>> +static const struct fpga_manager_ops xilinx_core_ops = {
>> + .state = xilinx_core_state,
>> + .write_init = xilinx_core_write_init,
>> + .write = xilinx_core_write,
>> + .write_complete = xilinx_core_write_complete,
>> +};
>> +
>> +int xilinx_core_probe(struct xilinx_fpga_core *core)
>> +{
>> + struct fpga_manager *mgr;
>> +
>> + if (!core || !core->dev || !core->write)
>> + return -EINVAL;
>> +
>> + /* PROGRAM_B is active low */
>> + core->prog_b = devm_gpiod_get(core->dev, "prog_b", GPIOD_OUT_LOW);
>> + if (IS_ERR(core->prog_b))
>> + return dev_err_probe(core->dev, PTR_ERR(core->prog_b),
>> + "Failed to get PROGRAM_B gpio\n");
>> +
>> + core->init_b = devm_gpiod_get_optional(core->dev, "init-b", GPIOD_IN);
>> + if (IS_ERR(core->init_b))
>> + return dev_err_probe(core->dev, PTR_ERR(core->init_b),
>> + "Failed to get INIT_B gpio\n");
>> +
>> + core->done = devm_gpiod_get(core->dev, "done", GPIOD_IN);
>> + if (IS_ERR(core->done))
>> + return dev_err_probe(core->dev, PTR_ERR(core->done),
>> + "Failed to get DONE gpio\n");
>> +
>> + mgr = devm_fpga_mgr_register(core->dev,
>> + "Xilinx Slave Serial FPGA Manager",
>> + &xilinx_core_ops, core);
>> + return PTR_ERR_OR_ZERO(mgr);
>> +}
>
> EXPORT_SYMBOL_GPL() is needed? Have you ever built them as modules?
> Try to follow Documentation/process/submit-checklist.rst as much as you can.
>
>
> And MODULE_LICENSE() & MODULE_DESCRIPTION() please.
>
Yes, there are some missing symbol info when building as a module. Will fix.
>> diff --git a/drivers/fpga/xilinx-core.h b/drivers/fpga/xilinx-core.h
>> new file mode 100644
>> index 0000000000000..bea190287b403
>> --- /dev/null
>> +++ b/drivers/fpga/xilinx-core.h
>> @@ -0,0 +1,28 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +
>> +#ifndef __XILINX_CORE_H
>> +#define __XILINX_CORE_H
>> +
>> +#include <linux/device.h>
>> +
>> +/**
>> + * struct xilinx_fpga_core - interface between the driver and the core manager
>> + * of Xilinx 7 Series FPGA manager
>> + * @dev: device node, must be set by the driver
>> + * @write: write callback of the driver, must be set by the driver
>> + * @prog_b: PROGRAM_B gpio, handled by the core manager
>> + * @init_b: INIT_B gpio, handled by the core manager
>> + * @done: DONE gpio, handled by the core manager
>
> Internal fields are not listed in the generated output documentation.
>
Ok, will remove.
>> + */
>> +struct xilinx_fpga_core {
>> + struct device *dev;
>> + int (*write)(struct xilinx_fpga_core *core, const char *buf,
>> + size_t count);
>> + struct gpio_desc *prog_b;
>> + struct gpio_desc *init_b;
>> + struct gpio_desc *done;
>
> Use private tag here.
>
> Please follow Documentation/doc-guide/kernel-doc.rst
>
Didn't knew about that, thank you!
>> +};
>> +
>> +int xilinx_core_probe(struct xilinx_fpga_core *core);
>> +
>> +#endif /* __XILINX_CORE_H */
>> diff --git a/drivers/fpga/xilinx-spi.c b/drivers/fpga/xilinx-spi.c
>> index e1a227e7ff2ae..12f401502a53a 100644
>> --- a/drivers/fpga/xilinx-spi.c
>> +++ b/drivers/fpga/xilinx-spi.c
>> @@ -10,127 +10,24 @@
>> * the slave serial configuration interface.
>> */
>>
>> -#include <linux/delay.h>
>> -#include <linux/device.h>
>> -#include <linux/fpga/fpga-mgr.h>
>> -#include <linux/gpio/consumer.h>
>> +#include "xilinx-core.h"
>> +
>> #include <linux/module.h>
>> #include <linux/mod_devicetable.h>
>> #include <linux/of.h>
>> #include <linux/spi/spi.h>
>> -#include <linux/sizes.h>
>>
>> struct xilinx_spi_conf {
>> + struct xilinx_fpga_core core;
>> struct spi_device *spi;
>> - struct gpio_desc *prog_b;
>> - struct gpio_desc *init_b;
>> - struct gpio_desc *done;
>> };
>>
>> -static int get_done_gpio(struct fpga_manager *mgr)
>> -{
>> - struct xilinx_spi_conf *conf = mgr->priv;
>> - int ret;
>> -
>> - ret = gpiod_get_value(conf->done);
>> -
>> - if (ret < 0)
>> - dev_err(&mgr->dev, "Error reading DONE (%d)\n", ret);
>> -
>> - return ret;
>> -}
>> -
>> -static enum fpga_mgr_states xilinx_spi_state(struct fpga_manager *mgr)
>> -{
>> - if (!get_done_gpio(mgr))
>> - return FPGA_MGR_STATE_RESET;
>> -
>> - return FPGA_MGR_STATE_UNKNOWN;
>> -}
>> -
>> -/**
>> - * wait_for_init_b - wait for the INIT_B pin to have a given state, or wait
>> - * a given delay if the pin is unavailable
>> - *
>> - * @mgr: The FPGA manager object
>> - * @value: Value INIT_B to wait for (1 = asserted = low)
>> - * @alt_udelay: Delay to wait if the INIT_B GPIO is not available
>> - *
>> - * Returns 0 when the INIT_B GPIO reached the given state or -ETIMEDOUT if
>> - * too much time passed waiting for that. If no INIT_B GPIO is available
>> - * then always return 0.
>> - */
>> -static int wait_for_init_b(struct fpga_manager *mgr, int value,
>> - unsigned long alt_udelay)
>> -{
>> - struct xilinx_spi_conf *conf = mgr->priv;
>> - unsigned long timeout = jiffies + msecs_to_jiffies(1000);
>> -
>> - if (conf->init_b) {
>> - while (time_before(jiffies, timeout)) {
>> - int ret = gpiod_get_value(conf->init_b);
>> -
>> - if (ret == value)
>> - return 0;
>> -
>> - if (ret < 0) {
>> - dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
>> - return ret;
>> - }
>> -
>> - usleep_range(100, 400);
>> - }
>> -
>> - dev_err(&mgr->dev, "Timeout waiting for INIT_B to %s\n",
>> - value ? "assert" : "deassert");
>> - return -ETIMEDOUT;
>> - }
>> -
>> - udelay(alt_udelay);
>> -
>> - return 0;
>> -}
>> -
>> -static int xilinx_spi_write_init(struct fpga_manager *mgr,
>> - struct fpga_image_info *info,
>> - const char *buf, size_t count)
>> -{
>> - struct xilinx_spi_conf *conf = mgr->priv;
>> - int err;
>> -
>> - if (info->flags & FPGA_MGR_PARTIAL_RECONFIG) {
>> - dev_err(&mgr->dev, "Partial reconfiguration not supported\n");
>> - return -EINVAL;
>> - }
>> -
>> - gpiod_set_value(conf->prog_b, 1);
>> -
>> - err = wait_for_init_b(mgr, 1, 1); /* min is 500 ns */
>> - if (err) {
>> - gpiod_set_value(conf->prog_b, 0);
>> - return err;
>> - }
>> -
>> - gpiod_set_value(conf->prog_b, 0);
>> +#define to_xilinx_spi_conf(obj) container_of(obj, struct xilinx_spi_conf, core)
>
> Use to_spi_device(), then no need the MACRO or struct xilinx_spi_conf
>
> Thanks,
> Yilun
>
Ok, good idea.
Thank you for the review, I'll send a v5 in ~2 weeks as I don't have access to my hw
right now.
Regards,
Charles
>>
>> - err = wait_for_init_b(mgr, 0, 0);
>> - if (err)
>> - return err;
>> -
>> - if (get_done_gpio(mgr)) {
>> - dev_err(&mgr->dev, "Unexpected DONE pin state...\n");
>> - return -EIO;
>> - }
>> -
>> - /* program latency */
>> - usleep_range(7500, 7600);
>> - return 0;
>> -}
>> -
>> -static int xilinx_spi_write(struct fpga_manager *mgr, const char *buf,
>> +static int xilinx_spi_write(struct xilinx_fpga_core *core, const char *buf,
>> size_t count)
>> {
>> - struct xilinx_spi_conf *conf = mgr->priv;
>> + struct xilinx_spi_conf *conf = to_xilinx_spi_conf(core);
>> const char *fw_data = buf;
>> const char *fw_data_end = fw_data + count;
>>
>> @@ -143,7 +40,7 @@ static int xilinx_spi_write(struct fpga_manager *mgr, const
>> char *buf,
>>
>> ret = spi_write(conf->spi, fw_data, stride);
>> if (ret) {
>> - dev_err(&mgr->dev, "SPI error in firmware write: %d\n",
>> + dev_err(core->dev, "SPI error in firmware write: %d\n",
>> ret);
>> return ret;
>> }
>> @@ -153,109 +50,26 @@ static int xilinx_spi_write(struct fpga_manager *mgr,
>> const char *buf,
>> return 0;
>> }
>>
>> -static int xilinx_spi_apply_cclk_cycles(struct xilinx_spi_conf *conf)
>> -{
>> - struct spi_device *spi = conf->spi;
>> - const u8 din_data[1] = { 0xff };
>> - int ret;
>> -
>> - ret = spi_write(conf->spi, din_data, sizeof(din_data));
>> - if (ret)
>> - dev_err(&spi->dev, "applying CCLK cycles failed: %d\n", ret);
>> -
>> - return ret;
>> -}
>> -
>> -static int xilinx_spi_write_complete(struct fpga_manager *mgr,
>> - struct fpga_image_info *info)
>> -{
>> - struct xilinx_spi_conf *conf = mgr->priv;
>> - unsigned long timeout = jiffies +
>> usecs_to_jiffies(info->config_complete_timeout_us);
>> - bool expired = false;
>> - int done;
>> - int ret;
>> -
>> - /*
>> - * This loop is carefully written such that if the driver is
>> - * scheduled out for more than 'timeout', we still check for DONE
>> - * before giving up and we apply 8 extra CCLK cycles in all cases.
>> - */
>> - while (!expired) {
>> - expired = time_after(jiffies, timeout);
>> -
>> - done = get_done_gpio(mgr);
>> - if (done < 0)
>> - return done;
>> -
>> - ret = xilinx_spi_apply_cclk_cycles(conf);
>> - if (ret)
>> - return ret;
>> -
>> - if (done)
>> - return 0;
>> - }
>> -
>> - if (conf->init_b) {
>> - ret = gpiod_get_value(conf->init_b);
>> -
>> - if (ret < 0) {
>> - dev_err(&mgr->dev, "Error reading INIT_B (%d)\n", ret);
>> - return ret;
>> - }
>> -
>> - dev_err(&mgr->dev,
>> - ret ? "CRC error or invalid device\n"
>> - : "Missing sync word or incomplete bitstream\n");
>> - } else {
>> - dev_err(&mgr->dev, "Timeout after config data transfer\n");
>> - }
>> -
>> - return -ETIMEDOUT;
>> -}
>> -
>> -static const struct fpga_manager_ops xilinx_spi_ops = {
>> - .state = xilinx_spi_state,
>> - .write_init = xilinx_spi_write_init,
>> - .write = xilinx_spi_write,
>> - .write_complete = xilinx_spi_write_complete,
>> -};
>> -
>> static int xilinx_spi_probe(struct spi_device *spi)
>> {
>> struct xilinx_spi_conf *conf;
>> - struct fpga_manager *mgr;
>>
>> conf = devm_kzalloc(&spi->dev, sizeof(*conf), GFP_KERNEL);
>> if (!conf)
>> return -ENOMEM;
>>
>> + conf->core.dev = &spi->dev;
>> + conf->core.write = xilinx_spi_write;
>> conf->spi = spi;
>>
>> - /* PROGRAM_B is active low */
>> - conf->prog_b = devm_gpiod_get(&spi->dev, "prog_b", GPIOD_OUT_LOW);
>> - if (IS_ERR(conf->prog_b))
>> - return dev_err_probe(&spi->dev, PTR_ERR(conf->prog_b),
>> - "Failed to get PROGRAM_B gpio\n");
>> -
>> - conf->init_b = devm_gpiod_get_optional(&spi->dev, "init-b", GPIOD_IN);
>> - if (IS_ERR(conf->init_b))
>> - return dev_err_probe(&spi->dev, PTR_ERR(conf->init_b),
>> - "Failed to get INIT_B gpio\n");
>> -
>> - conf->done = devm_gpiod_get(&spi->dev, "done", GPIOD_IN);
>> - if (IS_ERR(conf->done))
>> - return dev_err_probe(&spi->dev, PTR_ERR(conf->done),
>> - "Failed to get DONE gpio\n");
>> -
>> - mgr = devm_fpga_mgr_register(&spi->dev,
>> - "Xilinx Slave Serial FPGA Manager",
>> - &xilinx_spi_ops, conf);
>> - return PTR_ERR_OR_ZERO(mgr);
>> + return xilinx_core_probe(&conf->core);
>> }
>>
>> #ifdef CONFIG_OF
>> static const struct of_device_id xlnx_spi_of_match[] = {
>> - { .compatible = "xlnx,fpga-slave-serial", },
>> + {
>> + .compatible = "xlnx,fpga-slave-serial",
>> + },
>> {}
>> };
>> MODULE_DEVICE_TABLE(of, xlnx_spi_of_match);
>> --
>> 2.43.0
>>