Re: [PATCH v2 4/4] fpga: dfl: add support for N3000 nios private feature

From: Tom Rix
Date: Sat Aug 01 2020 - 11:36:09 EST

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See below.

On 7/31/20 1:56 AM, Xu Yilun wrote:
> On Sat, Jul 25, 2020 at 07:53:59AM -0700, Tom Rix wrote:
>> 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 ?
> I think we don't have to add this. The driver doesn't call any API
> provided by SPI core, just fills the spi_board_info structure.
ok
>
>>> + 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.
> Yes, I'll add the documents.
>
>>> +
>>> +/* 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.
> Yes.
>
>>> +
>>> +#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'
> Yes.
>
>>> +};
>>> +
>>> +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.
> I think it may not be necessary. It is not reasonable n3000_nios_readl()
> has the return type ssize_t. So no matter how you define the ret, the
> cast is always needed.
>
> I see the general handling of this case in drivers is "int ret".

Ok.

>
>>> +
>>> + 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
> Yes.
>
>>> +{
>>> + 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
> Yes, I could improve this.
>
>>> + 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
> Yes, I could add the error log.
>
>>> +
>>> + 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.
> We do use strcmp here, so are we OK here?
Yes.
>>> + 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
> Yes
>
>>> +{
>>> + 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.
> Time based timeout is more reasonable, but it will drop the performance:
> 1. The indirect bus is accessed so frequently. It is on the critical
> path of FPGA image flashing.
> 2. The state change time is very short, usually in 1 or 2 loops.
>
> We've profiled that if we add time check here then, FPGA image flash
> time would be several minutes longer.
>
> Anyway, 10000 times loop is large enough.
As this is unusual, please add a comment with this explanation.
>> Could this polling be switch to interrupt ?
> We don't have interrupt source here.
>
>>> +
>>> + /*
>>> + * 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_' ?
> It is the abbreviation of nios_spi, is that OK?
> I don't want a long prefix for everything, but still want a namespace.
Ok, then add a comment 'ns = nios_spi'
>> 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.
> I'm going to abstract the dfl-bus related stuff in a new head file,
> maybe we could change it when more dfl devices are added.

Yes. that is fine.

Reviewed-by: Tom Rix <trix@xxxxxxxxxx>

>
> Thanks,
> Yilun.
>
>>> +
>>> +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");

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