Mostly little stuff.
The polling on the int in ns_bus_poll_stat_timeout should be refactored.
Tom
On 7/23/20 7:09 PM, Xu Yilun wrote:
> This patch adds support for the nios handshake private feature on Intel
> N3000 FPGA Card. This private feature provides a handshake interface to
> FPGA NIOS firmware, which receives retimer configuration command from host
> and executes via an internal SPI master. When nios finished the
> configuration, host takes over the ownership of the SPI master to control
> an Intel MAX10 BMC Chip on the SPI bus.
>
> For NIOS firmware handshake part, this driver requests the retimer
> configuration for NIOS with parameters from module param, and adds some
> sysfs nodes for user to query NIOS state.
>
> For SPI part, this driver adds a spi-altera platform device as well as
> the MAX10 BMC spi slave info. A spi-altera driver will be matched to
> handle following the SPI work.
>
> Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
> Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
> ---
> .../ABI/testing/sysfs-bus-dfl-devices-n3000-nios | 16 +
> drivers/fpga/Kconfig | 12 +
> drivers/fpga/Makefile | 2 +
> drivers/fpga/dfl-n3000-nios.c | 483 +++++++++++++++++++++
> 4 files changed, 513 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-dfl-devices-n3000-nios
> create mode 100644 drivers/fpga/dfl-n3000-nios.c
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-dfl-devices-n3000-nios b/Documentation/ABI/testing/sysfs-bus-dfl-devices-n3000-nios
> new file mode 100644
> index 0000000..8346b74
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-dfl-devices-n3000-nios
> @@ -0,0 +1,16 @@
> +What: /sys/bus/dfl/devices/dfl-fme.X.X/fec_mode
> +Date: July 2020
> +KernelVersion: 5.9
> +Contact: Xu Yilun <yilun.xu@xxxxxxxxx>
> +Description: Read-only. It returns the FEC mode of the ethernet retimer
> + configured by NIOS firmware. "rs" for RS FEC mode, "kr" for
> + KR FEC mode, "no" FOR NO FEC mode.
> + Format: string
> +
> +What: /sys/bus/dfl/devices/dfl-fme.X.X/nios_fw_version
> +Date: July 2020
> +KernelVersion: 5.9
> +Contact: Xu Yilun <yilun.xu@xxxxxxxxx>
> +Description: Read-only. It returns the NIOS firmware version in FPGA. Its
> + format is "major.minor.patch".
> + Format: %x.%x.%x
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index b2408a7..fa5f3ab 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -191,6 +191,18 @@ config FPGA_DFL_AFU
> to the FPGA infrastructure via a Port. There may be more than one
> Port/AFU per DFL based FPGA device.
>
> +config FPGA_DFL_N3000_NIOS
> + tristate "FPGA DFL N3000 NIOS Driver"
> + depends on FPGA_DFL
> + select REGMAP
depends on SPI_MASTER ?
> + help
> + This is the driver for the nios handshake private feature on Intel
> + N3000 FPGA Card. This private feature provides a handshake interface
> + to FPGA NIOS firmware, which receives retimer configuration command
> + from host and executes via an internal SPI master. When nios finished
> + the configuration, host takes over the ownership of the SPI master to
> + control an Intel MAX10 BMC Chip on the SPI bus.
> +
> config FPGA_DFL_PCI
> tristate "FPGA DFL PCIe Device Driver"
> depends on PCI && FPGA_DFL
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> index d8e21df..27f20f2 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -44,5 +44,7 @@ dfl-fme-objs += dfl-fme-perf.o
> dfl-afu-objs := dfl-afu-main.o dfl-afu-region.o dfl-afu-dma-region.o
> dfl-afu-objs += dfl-afu-error.o
>
> +obj-$(CONFIG_FPGA_DFL_N3000_NIOS) += dfl-n3000-nios.o
> +
> # Drivers for FPGAs which implement DFL
> obj-$(CONFIG_FPGA_DFL_PCI) += dfl-pci.o
> diff --git a/drivers/fpga/dfl-n3000-nios.c b/drivers/fpga/dfl-n3000-nios.c
> new file mode 100644
> index 0000000..d098a10
> --- /dev/null
> +++ b/drivers/fpga/dfl-n3000-nios.c
> @@ -0,0 +1,483 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for DFL N3000 NIOS private feature
> + *
> + * Copyright (C) 2019-2020 Intel Corporation, Inc.
> + *
> + * Authors:
> + * Wu Hao <hao.wu@xxxxxxxxx>
> + * Xu Yilun <yilun.xu@xxxxxxxxx>
> + */
> +#include <linux/bitfield.h>
> +#include <linux/errno.h>
> +#include <linux/io.h>
> +#include <linux/io-64-nonatomic-lo-hi.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/stddef.h>
> +#include <linux/spi/altera.h>
> +#include <linux/spi/spi.h>
> +#include <linux/types.h>
> +
> +#include "dfl.h"
> +
> +static char *fec_mode = "rs";
> +module_param(fec_mode, charp, 0444);
> +MODULE_PARM_DESC(child, "FEC mode");
Should document what the valid values are and what they mean.
ex/ what is 'rs' ?
Maybe append something in the sysfs doc about fec_mode being settable.
> +
> +/* N3000 NIOS private feature registers */
> +#define NIOS_SPI_PARAM 0x8
> +#define SHIFT_MODE BIT_ULL(1)
> +#define SHIFT_MODE_MSB 0
> +#define SHIFT_MODE_LSB 1
> +#define DATA_WIDTH GENMASK_ULL(7, 2)
> +#define NUM_CHIPSELECT GENMASK_ULL(13, 8)
> +#define CLK_POLARITY BIT_ULL(14)
> +#define CLK_PHASE BIT_ULL(15)
> +#define PERIPHERAL_ID GENMASK_ULL(47, 32)
> +
> +#define NIOS_SPI_CTRL 0x10
> +#define CTRL_WR_DATA GENMASK_ULL(31, 0)
> +#define CTRL_ADDR GENMASK_ULL(44, 32)
> +#define CTRL_CMD GENMASK_ULL(63, 62)
> +#define CMD_NOP 0
> +#define CMD_RD 1
> +#define CMD_WR 2
These are fairly generic #define names, consider adding a prefix.
> +
> +#define NIOS_SPI_STAT 0x18
> +#define STAT_RD_DATA GENMASK_ULL(31, 0)
> +#define STAT_RW_VAL BIT_ULL(32)
> +
> +/* nios handshake registers, indirect access */
> +#define NIOS_INIT 0x1000
> +#define NIOS_INIT_DONE BIT(0)
> +#define NIOS_INIT_START BIT(1)
> +/* Mode for PKVL A, link 0, the same below */
> +#define REQ_FEC_MODE_A0 GENMASK(9, 8)
> +#define REQ_FEC_MODE_A1 GENMASK(11, 10)
> +#define REQ_FEC_MODE_A2 GENMASK(13, 12)
> +#define REQ_FEC_MODE_A3 GENMASK(15, 14)
> +#define REQ_FEC_MODE_B0 GENMASK(17, 16)
> +#define REQ_FEC_MODE_B1 GENMASK(19, 18)
> +#define REQ_FEC_MODE_B2 GENMASK(21, 20)
> +#define REQ_FEC_MODE_B3 GENMASK(23, 22)
> +#define FEC_MODE_NO 0x0
> +#define FEC_MODE_KR 0x1
> +#define FEC_MODE_RS 0x2
> +
> +#define NIOS_FW_VERSION 0x1004
> +#define NIOS_FW_VERSION_PATCH GENMASK(23, 20)
> +#define NIOS_FW_VERSION_MINOR GENMASK(27, 24)
> +#define NIOS_FW_VERSION_MAJOR GENMASK(31, 28)
> +
> +#define PKVL_A_MODE_STS 0x1020
> +#define PKVL_B_MODE_STS 0x1024
> +
> +#define NS_REGBUS_WAIT_TIMEOUT 10000 /* loop count */
> +#define NIOS_INIT_TIMEOUT 10000000 /* usec */
> +#define NIOS_INIT_TIME_INTV 100000 /* usec */
> +
> +struct dfl_n3000_nios {
> + void __iomem *base;
> + struct regmap *regmap;
> + struct device *dev;
> + struct platform_device *altr_spi;
Make this element more meaningful, expand to 'altera_spi'
> +};
> +
> +static int n3000_nios_writel(struct dfl_n3000_nios *ns, unsigned int reg,
> + unsigned int val)
> +{
> + int ret;
> +
> + ret = regmap_write(ns->regmap, reg, val);
> + if (ret)
> + dev_err(ns->dev, "fail to write reg 0x%x val 0x%x: %d\n",
> + reg, val, ret);
> +
> + return ret;
> +}
> +
> +static int n3000_nios_readl(struct dfl_n3000_nios *ns, unsigned int reg,
> + unsigned int *val)
> +{
> + int ret;
> +
> + ret = regmap_read(ns->regmap, reg, val);
> + if (ret)
> + dev_err(ns->dev, "fail to read reg 0x%x: %d\n", reg, ret);
> +
> + return ret;
> +}
> +
> +static ssize_t nios_fw_version_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct dfl_n3000_nios *ns = dev_get_drvdata(dev);
> + unsigned int val;
> + int ret;
This and similar could be
ssize_t ret.
> +
> + ret = n3000_nios_readl(ns, NIOS_FW_VERSION, &val);
> + if (ret)
> + return ret;
> +
> + return sprintf(buf, "%x.%x.%x\n",
> + (u8)FIELD_GET(NIOS_FW_VERSION_MAJOR, val),
> + (u8)FIELD_GET(NIOS_FW_VERSION_MINOR, val),
> + (u8)FIELD_GET(NIOS_FW_VERSION_PATCH, val));
> +}
> +static DEVICE_ATTR_RO(nios_fw_version);
> +
> +static ssize_t fec_mode_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct dfl_n3000_nios *ns = dev_get_drvdata(dev);
> + unsigned int val, mode;
> + int ret;
> +
> + ret = n3000_nios_readl(ns, NIOS_INIT, &val);
> + if (ret)
> + return ret;
> +
> + /*
> + * FEC mode should always be the same for all links, as we set them
> + * in this way.
> + */
> + mode = FIELD_GET(REQ_FEC_MODE_A0, val);
> + if (mode != FIELD_GET(REQ_FEC_MODE_A1, val) ||
> + mode != FIELD_GET(REQ_FEC_MODE_A2, val) ||
> + mode != FIELD_GET(REQ_FEC_MODE_A3, val) ||
> + mode != FIELD_GET(REQ_FEC_MODE_B0, val) ||
> + mode != FIELD_GET(REQ_FEC_MODE_B1, val) ||
> + mode != FIELD_GET(REQ_FEC_MODE_B2, val) ||
> + mode != FIELD_GET(REQ_FEC_MODE_B3, val))
> + return -EFAULT;
> +
> + switch (mode) {
> + case FEC_MODE_NO:
> + return sprintf(buf, "no\n");
> + case FEC_MODE_KR:
> + return sprintf(buf, "kr\n");
> + case FEC_MODE_RS:
> + return sprintf(buf, "rs\n");
> + }
> +
> + return -EFAULT;
> +}
> +static DEVICE_ATTR_RO(fec_mode);
> +
> +static struct attribute *n3000_nios_attrs[] = {
> + &dev_attr_nios_fw_version.attr,
> + &dev_attr_fec_mode.attr,
> + NULL,
> +};
> +ATTRIBUTE_GROUPS(n3000_nios);
> +
> +static int init_error_detected(struct dfl_n3000_nios *ns)
returning true/false, the return type should be boolean
> +{
> + unsigned int val;
> +
> + if (n3000_nios_readl(ns, PKVL_A_MODE_STS, &val))
> + return true;
> +
> + if (val >= 0x100)
A magic number like 0x100 should be #define-ed.
similar below
> + return true;
> +
> + if (n3000_nios_readl(ns, PKVL_B_MODE_STS, &val))
> + return true;
> +
> + if (val >= 0x100)
> + return true;
> +
> + return false;
> +}
> +
> +static void dump_error_stat(struct dfl_n3000_nios *ns)
> +{
> + unsigned int val;
> +
> + if (n3000_nios_readl(ns, PKVL_A_MODE_STS, &val))
> + return;
Not being able to read the register is itself and error.
Should add something like 'Could not read register PKVL_A_MODE_STS'
similar below
> +
> + dev_info(ns->dev, "PKVL_A_MODE_STS %x\n", val);
> +
> + if (n3000_nios_readl(ns, PKVL_B_MODE_STS, &val))
> + return;
> +
> + dev_info(ns->dev, "PKVL_B_MODE_STS %x\n", val);
> +}
> +
> +static int n3000_nios_init_done_check(struct dfl_n3000_nios *ns)
> +{
> + struct device *dev = ns->dev;
> + unsigned int val, mode;
> + int ret;
> +
> + /*
> + * this SPI is shared by NIOS core inside FPGA, NIOS will use this SPI
> + * master to do some one time initialization after power up, and then
> + * release the control to OS. driver needs to poll on INIT_DONE to
> + * see when driver could take the control.
> + *
> + * Please note that after 3.x.x version, INIT_START is introduced, so
> + * driver needs to trigger START firstly and then check INIT_DONE.
> + */
> +
> + ret = n3000_nios_readl(ns, NIOS_FW_VERSION, &val);
> + if (ret)
> + return ret;
> +
> + /*
> + * If NIOS version register is totally uninitialized(== 0x0), then the
> + * NIOS firmware is missing. So host could take control of SPI master
> + * safely, but initialization work for NIOS is not done. This is an
> + * issue of FPGA image. We didn't error out because we need SPI master
> + * to reprogram a new image.
> + */
> + if (val == 0) {
> + dev_warn(dev, "NIOS version reg = 0x%x, skip INIT_DONE check, but PKVL may be uninitialized\n",
> + val);
> + return 0;
> + }
> +
> + if (FIELD_GET(NIOS_FW_VERSION_MAJOR, val) >= 3) {
> + /* read NIOS_INIT to check if PKVL INIT done or not */
> + ret = n3000_nios_readl(ns, NIOS_INIT, &val);
> + if (ret)
> + return ret;
> +
> + /* check if PKVLs are initialized already */
> + if (val & NIOS_INIT_DONE || val & NIOS_INIT_START)
> + goto nios_init_done;
> +
> + /* configure FEC mode per module param */
> + val = NIOS_INIT_START;
> +
> + /* FEC mode will be ignored by hardware in 10G mode */
> + if (!strcmp(fec_mode, "no"))
strncmp is safer but would lead to 'no123' being valid.
> + mode = FEC_MODE_NO;
> + else if (!strcmp(fec_mode, "kr"))
> + mode = FEC_MODE_KR;
> + else if (!strcmp(fec_mode, "rs"))
> + mode = FEC_MODE_RS;
> + else
> + return -EINVAL;
> +
> + /* set the same FEC mode for all links */
> + val |= FIELD_PREP(REQ_FEC_MODE_A0, mode) |
> + FIELD_PREP(REQ_FEC_MODE_A1, mode) |
> + FIELD_PREP(REQ_FEC_MODE_A2, mode) |
> + FIELD_PREP(REQ_FEC_MODE_A3, mode) |
> + FIELD_PREP(REQ_FEC_MODE_B0, mode) |
> + FIELD_PREP(REQ_FEC_MODE_B1, mode) |
> + FIELD_PREP(REQ_FEC_MODE_B2, mode) |
> + FIELD_PREP(REQ_FEC_MODE_B3, mode);
> +
> + ret = n3000_nios_writel(ns, NIOS_INIT, val);
> + if (ret)
> + return ret;
> + }
> +
> +nios_init_done:
> + /* polls on NIOS_INIT_DONE */
> + ret = regmap_read_poll_timeout(ns->regmap, NIOS_INIT, val,
> + val & NIOS_INIT_DONE,
> + NIOS_INIT_TIME_INTV,
> + NIOS_INIT_TIMEOUT);
> + if (ret) {
> + dev_err(dev, "NIOS_INIT_DONE %s\n",
> + (ret == -ETIMEDOUT) ? "timed out" : "check error");
> + goto dump_sts;
> + }
> +
> + /*
> + * after INIT_DONE is detected, it still needs to check if any ERR
> + * detected.
> + * We won't error out here even if error detected. Nios will release
> + * spi controller when INIT_DONE is set, so driver could continue to
> + * initialize spi controller device.
> + */
> + if (init_error_detected(ns)) {
> + dev_warn(dev, "NIOS_INIT_DONE OK, but err found during init\n");
> + goto dump_sts;
> + }
> + return 0;
> +
> +dump_sts:
> + dump_error_stat(ns);
> +
> + return ret;
> +}
> +
> +struct spi_board_info m10_n3000_info = {
> + .modalias = "m10-n3000",
> + .max_speed_hz = 12500000,
> + .bus_num = 0,
> + .chip_select = 0,
> +};
> +
> +static int create_altr_spi_controller(struct dfl_n3000_nios *ns)
Also here, altr -> altera
> +{
> + struct altera_spi_platform_data pdata = { 0 };
> + struct platform_device_info pdevinfo = { 0 };
> + void __iomem *base = ns->base;
> + u64 v;
> +
> + v = readq(base + NIOS_SPI_PARAM);
> +
> + pdata.mode_bits = SPI_CS_HIGH;
> + if (FIELD_GET(CLK_POLARITY, v))
> + pdata.mode_bits |= SPI_CPOL;
> + if (FIELD_GET(CLK_PHASE, v))
> + pdata.mode_bits |= SPI_CPHA;
> +
> + pdata.num_chipselect = FIELD_GET(NUM_CHIPSELECT, v);
> + pdata.bits_per_word_mask =
> + SPI_BPW_RANGE_MASK(1, FIELD_GET(DATA_WIDTH, v));
> +
> + pdata.num_devices = 1;
> + pdata.devices = &m10_n3000_info;
> +
> + dev_dbg(ns->dev, "%s cs %u bpm 0x%x mode 0x%x\n", __func__,
> + pdata.num_chipselect, pdata.bits_per_word_mask,
> + pdata.mode_bits);
> +
> + pdevinfo.name = "subdev_spi_altera";
> + pdevinfo.id = PLATFORM_DEVID_AUTO;
> + pdevinfo.parent = ns->dev;
> + pdevinfo.data = &pdata;
> + pdevinfo.size_data = sizeof(pdata);
> +
> + ns->altr_spi = platform_device_register_full(&pdevinfo);
> + return PTR_ERR_OR_ZERO(ns->altr_spi);
> +}
> +
> +static void destroy_altr_spi_controller(struct dfl_n3000_nios *ns)
> +{
> + platform_device_unregister(ns->altr_spi);
> +}
> +
> +static int ns_bus_poll_stat_timeout(void __iomem *base, u64 *v)
> +{
> + int loops = NS_REGBUS_WAIT_TIMEOUT;
Would not this be better as time based timeout ?
Looping over int is only good if you know the clock freq etc.
Could this polling be switch to interrupt ?
> +
> + /*
> + * Usually the state changes in few loops, so we try to be simple here
> + * for performance.
> + */
> + do {
> + *v = readq(base + NIOS_SPI_STAT);
> + if (*v & STAT_RW_VAL)
> + break;
> + cpu_relax();
> + } while (--loops);
> +
> + return loops ? 0 : -ETIMEDOUT;
> +}
> +
> +static int ns_bus_reg_write(void *context, unsigned int reg, unsigned int val)
what is 'ns_' ?
Maybe this should be 'nios_spi' or just drop the prefix.
> +{
> + void __iomem *base = context;
> + u64 v = 0;
> +
> + v |= FIELD_PREP(CTRL_CMD, CMD_WR);
> + v |= FIELD_PREP(CTRL_ADDR, reg);
> + v |= FIELD_PREP(CTRL_WR_DATA, val);
> + writeq(v, base + NIOS_SPI_CTRL);
> +
> + return ns_bus_poll_stat_timeout(base, &v);
> +}
> +
> +static int ns_bus_reg_read(void *context, unsigned int reg, unsigned int *val)
> +{
> + void __iomem *base = context;
> + u64 v = 0;
> + int ret;
> +
> + v |= FIELD_PREP(CTRL_CMD, CMD_RD);
> + v |= FIELD_PREP(CTRL_ADDR, reg);
> + writeq(v, base + NIOS_SPI_CTRL);
> +
> + ret = ns_bus_poll_stat_timeout(base, &v);
> + if (!ret)
> + *val = FIELD_GET(STAT_RD_DATA, v);
> +
> + return ret;
> +}
> +
> +static const struct regmap_config ns_regbus_cfg = {
> + .reg_bits = 32,
> + .reg_stride = 4,
> + .val_bits = 32,
> + .fast_io = true,
> +
> + .reg_write = ns_bus_reg_write,
> + .reg_read = ns_bus_reg_read,
> +};
> +
> +static int dfl_n3000_nios_probe(struct dfl_device *dfl_dev)
> +{
> + struct device *dev = &dfl_dev->dev;
> + struct dfl_n3000_nios *ns;
> + int ret;
> +
> + ns = devm_kzalloc(dev, sizeof(*ns), GFP_KERNEL);
> + if (!ns)
> + return -ENOMEM;
> +
> + dev_set_drvdata(&dfl_dev->dev, ns);
> +
> + ns->dev = dev;
> +
> + ns->base = devm_ioremap_resource(&dfl_dev->dev, &dfl_dev->mmio_res);
> + if (IS_ERR(ns->base)) {
> + dev_err(dev, "get mem resource fail!\n");
> + return PTR_ERR(ns->base);
> + }
> +
> + ns->regmap = devm_regmap_init(dev, NULL, ns->base, &ns_regbus_cfg);
> + if (IS_ERR(ns->regmap))
> + return PTR_ERR(ns->regmap);
> +
> + ret = n3000_nios_init_done_check(ns);
> + if (ret)
> + return ret;
> +
> + ret = create_altr_spi_controller(ns);
> + if (ret)
> + dev_err(dev, "altr spi controller create failed: %d\n", ret);
> +
> + return ret;
> +}
> +
> +static void dfl_n3000_nios_remove(struct dfl_device *dfl_dev)
> +{
> + struct dfl_n3000_nios *ns = dev_get_drvdata(&dfl_dev->dev);
> +
> + destroy_altr_spi_controller(ns);
> +}
> +
> +#define FME_FEATURE_ID_N3000_NIOS 0xd
To minimize collisions, maybe collect these to a new common header like 'dfl-features-ids.h' or just add to some other visible existing header.
> +
> +static const struct dfl_device_id dfl_n3000_nios_ids[] = {
> + { FME_ID, FME_FEATURE_ID_N3000_NIOS },
> + { }
> +};
> +
> +static struct dfl_driver dfl_n3000_nios_driver = {
> + .drv = {
> + .name = "dfl-n3000-nios",
> + .dev_groups = n3000_nios_groups,
> + },
> + .id_table = dfl_n3000_nios_ids,
> + .probe = dfl_n3000_nios_probe,
> + .remove = dfl_n3000_nios_remove,
> +};
> +
> +module_dfl_driver(dfl_n3000_nios_driver);
> +
> +MODULE_DEVICE_TABLE(dfl, dfl_n3000_nios_ids);
> +MODULE_DESCRIPTION("DFL N3000 NIOS driver");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_LICENSE("GPL v2");
