Re: [PATCH v4 4/4] fpga: dfl: add support for N3000 Nios private feature

From: Xu Yilun
Date: Mon Aug 10 2020 - 12:19:17 EST

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On Mon, Aug 10, 2020 at 03:00:08PM +0800, Wu, Hao wrote:
> > Subject: [PATCH v4 4/4] fpga: dfl: add support for N3000 Nios private feature
> >
> > This patch adds support for the Nios handshake private feature on Intel
> > N3000 FPGA Card.
> >
> > The terminology "Nios" stands for the NIOS II - 32 bit embedded soft
> > processor designed for FPGAs. This private feature provides a handshake
> > interface to FPGA Nois firmware, which receives retimer configuration
> > command from host and executes via an internal SPI master. When Nios
> > finishes 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>
> > Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
> > ---
> > v3: Add the doc for this driver
> > Minor fixes for comments from Tom
> > v4: Move the err log in regmap implementation, and delete
> > n3000_nios_writel/readl(), they have nothing to wrapper now.
> > Some minor fixes and comments improvement.
> > ---
> > .../ABI/testing/sysfs-bus-dfl-devices-n3000-nios | 18 +
> > Documentation/fpga/dfl-n3000-nios.rst | 41 ++
> > Documentation/fpga/index.rst | 1 +
> > drivers/fpga/Kconfig | 12 +
> > drivers/fpga/Makefile | 2 +
> > drivers/fpga/dfl-n3000-nios.c | 475 +++++++++++++++++++++
> > 6 files changed, 549 insertions(+)
> > create mode 100644 Documentation/ABI/testing/sysfs-bus-dfl-devices-
> > n3000-nios
> > create mode 100644 Documentation/fpga/dfl-n3000-nios.rst
> > 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..4b2b9c5
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-dfl-devices-n3000-nios
> > @@ -0,0 +1,18 @@
> > +What:/sys/bus/dfl/devices/dfl_dev.X/fec_mode
> > +Date:July 2020
> > +KernelVersion:5.10
> > +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. The FEC mode could
> > be set
> > +by module parameters, but it could only be set once after the
> > +board powers up.
> > +Format: string
> > +
> > +What:/sys/bus/dfl/devices/dfl_dev.X/nios_fw_version
> > +Date:July 2020
> > +KernelVersion:5.10
> > +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/Documentation/fpga/dfl-n3000-nios.rst
> > b/Documentation/fpga/dfl-n3000-nios.rst
> > new file mode 100644
> > index 0000000..ecc14e3
> > --- /dev/null
> > +++ b/Documentation/fpga/dfl-n3000-nios.rst
> > @@ -0,0 +1,41 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +=====================================
> > +DFL N3000 Nios Private Feature Driver
> > +=====================================
> > +
> > +The dfl N3000 Nios driver supports for the Nios handshake private feature
> > on
> > +Intel N3000 FPGA Card.
> > +
> > +The terminology "Nios" stands for the NIOS II - 32 bit embedded soft
> > processor
> > +designed for FPGAs. This private feature provides a handshake interface to
> > FPGA
> > +Nios firmware, which receives the ethernet retimer configuration command
> > from
> > +host and does the configuration via an internal SPI master. When Nios
> > finishes
> > +the configuration, host takes over the ownership of the SPI master to
> > control
> > +an Intel MAX10 BMC Chip on the SPI bus.
> > +
> > +So the driver does 2 major tasks on probe, uses the Nios firmware to
> > configure
> > +the ethernet retimer, and then creates a spi master platform device with
> > the
> > +MAX10 device info in spi_board_info.
> > +
> > +Module Parameters
> > +=================
> > +
> > +The dfl N3000 Nios driver supports the following module parameters:
> > +
> > +* fec_mode: string
> > + Require the Nios firmware to set the FEC (Forward Error Correction) mode
> > of
> > + the ethernet retimer on the PAC N3000 FPGA card. The possible values
> > could
> > + be:
> > +
> > + - "rs": Reed Solomon FEC (default)
> > + - "kr": Fire Code FEC
> > + - "no": No FEC
> > +
> > + The configuration can only be set once after the board powers up, the
> > + firmware will not accept second configuration afterward. So the fec mode
> > + will not be changed if the module is reloaded with a different param value.
> > +
> > + The configured value of the fec mode could be queried from sysfs node:
> > +
> > + /sys/bus/dfl/devices/dfl_dev.X/fec_mode
> > diff --git a/Documentation/fpga/index.rst b/Documentation/fpga/index.rst
> > index f80f956..5fd3c37 100644
> > --- a/Documentation/fpga/index.rst
> > +++ b/Documentation/fpga/index.rst
> > @@ -8,6 +8,7 @@ fpga
> > :maxdepth: 1
> >
> > dfl
> > + dfl-n3000-nios
> >
> > .. only:: subproject and html
> >
> > diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> > index 7cd5a29..f820142 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
> > + 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..b3093a2
> > --- /dev/null
> > +++ b/drivers/fpga/dfl-n3000-nios.c
> > @@ -0,0 +1,475 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * DFL device driver for Nios private feature on Intel PAC N3000
> > + *
> > + * 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(fec_mode, "FEC mode of the ethernet retimer on
> > PAC N3000 FPGA card");
>
> Intel PAC..

Yes.

> > +
> > +/* N3000 Nios private feature registers */
> > +#define NIOS_SPI_PARAM0x8
> > +#define PARAM_SHIFT_MODE_MSKBIT_ULL(1)
> > +#define PARAM_SHIFT_MODE_MSB0
> > +#define PARAM_SHIFT_MODE_LSB1
> > +#define PARAM_DATA_WIDTHGENMASK_ULL(7, 2)
> > +#define PARAM_NUM_CSGENMASK_ULL(13, 8)
> > +#define PARAM_CLK_POLBIT_ULL(14)
> > +#define PARAM_CLK_PHASEBIT_ULL(15)
> > +#define PARAM_PERIPHERAL_IDGENMASK_ULL(47, 32)
> > +
> > +#define NIOS_SPI_CTRL0x10
> > +#define CTRL_WR_DATAGENMASK_ULL(31, 0)
> > +#define CTRL_ADDRGENMASK_ULL(44, 32)
> > +#define CTRL_CMD_MSKGENMASK_ULL(63, 62)
> > +#define CTRL_CMD_NOP0
> > +#define CTRL_CMD_RD1
> > +#define CTRL_CMD_WR2
> > +
> > +#define NIOS_SPI_STAT0x18
> > +#define STAT_RD_DATAGENMASK_ULL(31, 0)
> > +#define STAT_RW_VALBIT_ULL(32)
> > +
> > +/* Nios handshake registers, indirect access */
> > +#define NIOS_INIT0x1000
> > +#define NIOS_INIT_DONEBIT(0)
> > +#define NIOS_INIT_STARTBIT(1)
> > +/* Mode for PKVL A, link 0, the same below */
> > +#define REQ_FEC_MODE_A0_MSKGENMASK(9, 8)
> > +#define REQ_FEC_MODE_A1_MSKGENMASK(11, 10)
> > +#define REQ_FEC_MODE_A2_MSKGENMASK(13, 12)
> > +#define REQ_FEC_MODE_A3_MSKGENMASK(15, 14)
> > +#define REQ_FEC_MODE_B0_MSKGENMASK(17, 16)
> > +#define REQ_FEC_MODE_B1_MSKGENMASK(19, 18)
> > +#define REQ_FEC_MODE_B2_MSKGENMASK(21, 20)
> > +#define REQ_FEC_MODE_B3_MSKGENMASK(23, 22)
> > +#define REQ_FEC_MODE_NO0x0
> > +#define REQ_FEC_MODE_KR0x1
> > +#define REQ_FEC_MODE_RS0x2
> > +
> > +#define NIOS_FW_VERSION0x1004
> > +#define NIOS_FW_VERSION_PATCHGENMASK(23, 20)
> > +#define NIOS_FW_VERSION_MINORGENMASK(27, 24)
> > +#define NIOS_FW_VERSION_MAJORGENMASK(31, 28)
> > +
> > +#define PKVL_A_MODE_STS0x1020
> > +#define PKVL_B_MODE_STS0x1024
> > +#define PKVL_MODE_STS_GROUP_MSKGENMASK(15, 8)
> > +#define PKVL_MODE_STS_GROUP_OK0x0
> > +#define PKVL_MODE_STS_ID_MSKGENMASK(7, 0)
> > +
> > +#define NS_REGBUS_WAIT_TIMEOUT10000/* loop count */
> > +#define NIOS_INIT_TIMEOUT10000000/* usec */
> > +#define NIOS_INIT_TIME_INTV100000/* usec */
> > +
> > +struct dfl_n3000_nios {
> > +void __iomem *base;
> > +struct regmap *regmap;
> > +struct device *dev;
> > +struct platform_device *altera_spi;
> > +};
> > +
> > +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;
> > +
> > +ret = regmap_read(ns->regmap, 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 = regmap_read(ns->regmap, 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_MSK, val);
> > +if (mode != FIELD_GET(REQ_FEC_MODE_A1_MSK, val) ||
> > + mode != FIELD_GET(REQ_FEC_MODE_A2_MSK, val) ||
> > + mode != FIELD_GET(REQ_FEC_MODE_A3_MSK, val) ||
> > + mode != FIELD_GET(REQ_FEC_MODE_B0_MSK, val) ||
> > + mode != FIELD_GET(REQ_FEC_MODE_B1_MSK, val) ||
> > + mode != FIELD_GET(REQ_FEC_MODE_B2_MSK, val) ||
> > + mode != FIELD_GET(REQ_FEC_MODE_B3_MSK, val))
> > +return -EFAULT;
> > +
> > +switch (mode) {
> > +case REQ_FEC_MODE_NO:
> > +return sprintf(buf, "no\n");
> > +case REQ_FEC_MODE_KR:
> > +return sprintf(buf, "kr\n");
> > +case REQ_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 bool init_error_detected(struct dfl_n3000_nios *ns)
> > +{
> > +unsigned int val;
> > +
> > +if (regmap_read(ns->regmap, PKVL_A_MODE_STS, &val))
> > +return true;
> > +
> > +if (FIELD_GET(PKVL_MODE_STS_GROUP_MSK, val) ==
> > PKVL_MODE_STS_GROUP_OK)
> > +return true;
> > +
> > +if (regmap_read(ns->regmap, PKVL_B_MODE_STS, &val))
> > +return true;
> > +
> > +if (FIELD_GET(PKVL_MODE_STS_GROUP_MSK, val) ==
> > PKVL_MODE_STS_GROUP_OK)
> > +return true;
> > +
> > +return false;
> > +}
> > +
> > +static void dump_error_stat(struct dfl_n3000_nios *ns)
> > +{
> > +unsigned int val;
> > +
> > +if (regmap_read(ns->regmap, PKVL_A_MODE_STS, &val))
> > +return;
> > +
> > +dev_info(ns->dev, "PKVL_A_MODE_STS %x\n", val);
> > +
> > +if (regmap_read(ns->regmap, 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 = regmap_read(ns->regmap, 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",
>
> Seems no place introduced the PKVL or just use retimer to replace PKVL?

Yes.

>
> Thanks
> Hao
>
> > + val);
> > +return 0;
> > +}
> > +
> > +if (FIELD_GET(NIOS_FW_VERSION_MAJOR, val) >= 3) {
> > +/* read NIOS_INIT to check if PKVL INIT done or not */
> > +ret = regmap_read(ns->regmap, 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 */
>
> So always no fec mode from hardware? Or software should force it
> in 10G mode? Or 10G mode, below code can be skipped?

I'm not sure about the 10G mode behavior since HW ignores the config in
this case. I'll check it.

Thanks
Yilun

>
> > +if (!strcmp(fec_mode, "no"))
> > +mode = REQ_FEC_MODE_NO;
> > +else if (!strcmp(fec_mode, "kr"))
> > +mode = REQ_FEC_MODE_KR;
> > +else if (!strcmp(fec_mode, "rs"))
> > +mode = REQ_FEC_MODE_RS;
> > +else
> > +return -EINVAL;
> > +
> > +/* set the same FEC mode for all links */
> > +val |= FIELD_PREP(REQ_FEC_MODE_A0_MSK, mode) |
> > + FIELD_PREP(REQ_FEC_MODE_A1_MSK, mode) |
> > + FIELD_PREP(REQ_FEC_MODE_A2_MSK, mode) |
> > + FIELD_PREP(REQ_FEC_MODE_A3_MSK, mode) |
> > + FIELD_PREP(REQ_FEC_MODE_B0_MSK, mode) |
> > + FIELD_PREP(REQ_FEC_MODE_B1_MSK, mode) |
> > + FIELD_PREP(REQ_FEC_MODE_B2_MSK, mode) |
> > + FIELD_PREP(REQ_FEC_MODE_B3_MSK, mode);
> > +
> > +ret = regmap_write(ns->regmap, 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_altera_spi_controller(struct dfl_n3000_nios *ns)
> > +{
> > +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(PARAM_CLK_POL, v))
> > +pdata.mode_bits |= SPI_CPOL;
> > +if (FIELD_GET(PARAM_CLK_PHASE, v))
> > +pdata.mode_bits |= SPI_CPHA;
> > +
> > +pdata.num_chipselect = FIELD_GET(PARAM_NUM_CS, v);
> > +pdata.bits_per_word_mask =
> > +SPI_BPW_RANGE_MASK(1, FIELD_GET(PARAM_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->altera_spi = platform_device_register_full(&pdevinfo);
> > +return PTR_ERR_OR_ZERO(ns->altera_spi);
> > +}
> > +
> > +static void destroy_altera_spi_controller(struct dfl_n3000_nios *ns)
> > +{
> > +platform_device_unregister(ns->altera_spi);
> > +}
> > +
> > +/* ns is the abbreviation of nios_spi */
> > +static int ns_poll_stat_timeout(void __iomem *base, u64 *v)
> > +{
> > +int loops = NS_REGBUS_WAIT_TIMEOUT;
> > +
> > +/*
> > + * We don't use the time based timeout here for performance.
> > + *
> > + * The image reprograming engine is on max10 bmc chip, which is the
> > spi
> > + * device connected to altera spi controller. So the regbus read/write
> > + * is on the critical path of PAC N3000 image reprograming. And
> > usually
> > + * the state changes in few loops, the time based timeout checking
> > will
> > + * add too much overhead on it.
> > + *
> > + * Anyway, 10000 times loop is large enough.
> > + */
> > +do {
> > +*v = readq(base + NIOS_SPI_STAT);
> > +if (*v & STAT_RW_VAL)
> > +break;
> > +cpu_relax();
> > +} while (--loops);
> > +
> > +return loops ? 0 : -ETIMEDOUT;
> > +}
> > +
> > +static int ns_reg_write(void *context, unsigned int reg, unsigned int val)
> > +{
> > +struct dfl_n3000_nios *ns = context;
> > +u64 v = 0;
> > +int ret;
> > +
> > +v |= FIELD_PREP(CTRL_CMD_MSK, CTRL_CMD_WR);
> > +v |= FIELD_PREP(CTRL_ADDR, reg);
> > +v |= FIELD_PREP(CTRL_WR_DATA, val);
> > +writeq(v, ns->base + NIOS_SPI_CTRL);
> > +
> > +ret = ns_poll_stat_timeout(ns->base, &v);
> > +if (ret)
> > +dev_err(ns->dev, "fail to write reg 0x%x val 0x%x: %d\n",
> > +reg, val, ret);
> > +
> > +return ret;
> > +}
> > +
> > +static int ns_reg_read(void *context, unsigned int reg, unsigned int *val)
> > +{
> > +struct dfl_n3000_nios *ns = context;
> > +u64 v = 0;
> > +int ret;
> > +
> > +v |= FIELD_PREP(CTRL_CMD_MSK, CTRL_CMD_RD);
> > +v |= FIELD_PREP(CTRL_ADDR, reg);
> > +writeq(v, ns->base + NIOS_SPI_CTRL);
> > +
> > +ret = ns_poll_stat_timeout(ns->base, &v);
> > +if (ret)
> > +dev_err(ns->dev, "fail to read reg 0x%x: %d\n", reg, ret);
> > +else
> > +*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_reg_write,
> > +.reg_read = ns_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))
> > +return PTR_ERR(ns->base);
> > +
> > +ns->regmap = devm_regmap_init(dev, NULL, ns, &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_altera_spi_controller(ns);
> > +if (ret)
> > +dev_err(dev, "altera 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_altera_spi_controller(ns);
> > +}
> > +
> > +#define FME_FEATURE_ID_N3000_NIOS0xd
> > +
> > +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 private feature driver");
> > +MODULE_AUTHOR("Intel Corporation");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.7.4

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