Message-ID: <b92450e6-afca-638c-6eff-bfbcdbd89e9b@redhat.com>
Date:   Tue, 4 May 2021 07:08:52 -0700
From:   Tom Rix <trix@...hat.com>
To:     Lizhi Hou <lizhi.hou@...inx.com>, linux-kernel@...r.kernel.org
Cc:     linux-fpga@...r.kernel.org, maxz@...inx.com,
        sonal.santan@...inx.com, yliu@...inx.com, michal.simek@...inx.com,
        stefanos@...inx.com, devicetree@...r.kernel.org, mdf@...nel.org,
        robh@...nel.org, Max Zhen <max.zhen@...inx.com>
Subject: Re: [PATCH V5 XRT Alveo 16/20] fpga: xrt: clock driver


On 4/27/21 1:54 PM, Lizhi Hou wrote:
> Add clock driver. Clock is a hardware function discovered by walking
> xclbin metadata. A xrt device node will be created for it. Other part of
> driver configures clock through clock driver.
>
> Signed-off-by: Sonal Santan <sonal.santan@...inx.com>
> Signed-off-by: Max Zhen <max.zhen@...inx.com>
> Signed-off-by: Lizhi Hou <lizhi.hou@...inx.com>

v4 was also ok, please add my Reviewed-by line

Reviewed-by: Tom Rix <trix@...hat.com>

> ---
>   drivers/fpga/xrt/include/xleaf/clock.h |  29 ++
>   drivers/fpga/xrt/lib/xleaf/clock.c     | 652 +++++++++++++++++++++++++
>   2 files changed, 681 insertions(+)
>   create mode 100644 drivers/fpga/xrt/include/xleaf/clock.h
>   create mode 100644 drivers/fpga/xrt/lib/xleaf/clock.c
>
> diff --git a/drivers/fpga/xrt/include/xleaf/clock.h b/drivers/fpga/xrt/include/xleaf/clock.h
> new file mode 100644
> index 000000000000..6858473fd096
> --- /dev/null
> +++ b/drivers/fpga/xrt/include/xleaf/clock.h
> @@ -0,0 +1,29 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *	Lizhi Hou <Lizhi.Hou@...inx.com>
> + */
> +
> +#ifndef _XRT_CLOCK_H_
> +#define _XRT_CLOCK_H_
> +
> +#include "xleaf.h"
> +#include <linux/xrt/xclbin.h>
> +
> +/*
> + * CLOCK driver leaf calls.
> + */
> +enum xrt_clock_leaf_cmd {
> +	XRT_CLOCK_SET = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
> +	XRT_CLOCK_GET,
> +	XRT_CLOCK_VERIFY,
> +};
> +
> +struct xrt_clock_get {
> +	u16 freq;
> +	u32 freq_cnter;
> +};
> +
> +#endif	/* _XRT_CLOCK_H_ */
> diff --git a/drivers/fpga/xrt/lib/xleaf/clock.c b/drivers/fpga/xrt/lib/xleaf/clock.c
> new file mode 100644
> index 000000000000..7303be55c07a
> --- /dev/null
> +++ b/drivers/fpga/xrt/lib/xleaf/clock.c
> @@ -0,0 +1,652 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx Alveo FPGA Clock Wizard Driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *      Lizhi Hou<Lizhi.Hou@...inx.com>
> + *      Sonal Santan <sonals@...inx.com>
> + *      David Zhang <davidzha@...inx.com>
> + */
> +
> +#include <linux/mod_devicetable.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/regmap.h>
> +#include <linux/io.h>
> +#include "metadata.h"
> +#include "xleaf.h"
> +#include "xleaf/clock.h"
> +#include "xleaf/clkfreq.h"
> +
> +/* XRT_CLOCK_MAX_NUM_CLOCKS should be a concept from XCLBIN_ in the future */
> +#define XRT_CLOCK_MAX_NUM_CLOCKS	4
> +#define XRT_CLOCK_STATUS_MASK		0xffff
> +#define XRT_CLOCK_STATUS_MEASURE_START	0x1
> +#define XRT_CLOCK_STATUS_MEASURE_DONE	0x2
> +
> +#define XRT_CLOCK_STATUS_REG		0x4
> +#define XRT_CLOCK_CLKFBOUT_REG		0x200
> +#define XRT_CLOCK_CLKOUT0_REG		0x208
> +#define XRT_CLOCK_LOAD_SADDR_SEN_REG	0x25C
> +#define XRT_CLOCK_DEFAULT_EXPIRE_SECS	1
> +
> +#define CLOCK_ERR(clock, fmt, arg...)	\
> +	xrt_err((clock)->xdev, fmt "\n", ##arg)
> +#define CLOCK_WARN(clock, fmt, arg...)	\
> +	xrt_warn((clock)->xdev, fmt "\n", ##arg)
> +#define CLOCK_INFO(clock, fmt, arg...)	\
> +	xrt_info((clock)->xdev, fmt "\n", ##arg)
> +#define CLOCK_DBG(clock, fmt, arg...)	\
> +	xrt_dbg((clock)->xdev, fmt "\n", ##arg)
> +
> +#define XRT_CLOCK	"xrt_clock"
> +
> +XRT_DEFINE_REGMAP_CONFIG(clock_regmap_config);
> +
> +struct clock {
> +	struct xrt_device	*xdev;
> +	struct regmap		*regmap;
> +	struct mutex		clock_lock; /* clock dev lock */
> +
> +	const char		*clock_ep_name;
> +};
> +
> +/*
> + * Precomputed table with config0 and config2 register values together with
> + * target frequency. The steps are approximately 5 MHz apart. Table is
> + * generated by platform creation tool.
> + */
> +static const struct xmgnt_ocl_clockwiz {
> +	/* target frequency */
> +	u16 ocl;
> +	/* config0 register */
> +	u32 config0;
> +	/* config2 register */
> +	u32 config2;
> +} frequency_table[] = {
> +	/*1275.000*/ { 10, 0x02EE0C01, 0x0001F47F },
> +	/*1575.000*/ { 15, 0x02EE0F01, 0x00000069},
> +	/*1600.000*/ { 20, 0x00001001, 0x00000050},
> +	/*1600.000*/ { 25, 0x00001001, 0x00000040},
> +	/*1575.000*/ { 30, 0x02EE0F01, 0x0001F434},
> +	/*1575.000*/ { 35, 0x02EE0F01, 0x0000002D},
> +	/*1600.000*/ { 40, 0x00001001, 0x00000028},
> +	/*1575.000*/ { 45, 0x02EE0F01, 0x00000023},
> +	/*1600.000*/ { 50, 0x00001001, 0x00000020},
> +	/*1512.500*/ { 55, 0x007D0F01, 0x0001F41B},
> +	/*1575.000*/ { 60, 0x02EE0F01, 0x0000FA1A},
> +	/*1462.500*/ { 65, 0x02710E01, 0x0001F416},
> +	/*1575.000*/ { 70, 0x02EE0F01, 0x0001F416},
> +	/*1575.000*/ { 75, 0x02EE0F01, 0x00000015},
> +	/*1600.000*/ { 80, 0x00001001, 0x00000014},
> +	/*1487.500*/ { 85, 0x036B0E01, 0x0001F411},
> +	/*1575.000*/ { 90, 0x02EE0F01, 0x0001F411},
> +	/*1425.000*/ { 95, 0x00FA0E01, 0x0000000F},
> +	/*1600.000*/ { 100, 0x00001001, 0x00000010},
> +	/*1575.000*/ { 105, 0x02EE0F01, 0x0000000F},
> +	/*1512.500*/ { 110, 0x007D0F01, 0x0002EE0D},
> +	/*1437.500*/ { 115, 0x01770E01, 0x0001F40C},
> +	/*1575.000*/ { 120, 0x02EE0F01, 0x00007D0D},
> +	/*1562.500*/ { 125, 0x02710F01, 0x0001F40C},
> +	/*1462.500*/ { 130, 0x02710E01, 0x0000FA0B},
> +	/*1350.000*/ { 135, 0x01F40D01, 0x0000000A},
> +	/*1575.000*/ { 140, 0x02EE0F01, 0x0000FA0B},
> +	/*1450.000*/ { 145, 0x01F40E01, 0x0000000A},
> +	/*1575.000*/ { 150, 0x02EE0F01, 0x0001F40A},
> +	/*1550.000*/ { 155, 0x01F40F01, 0x0000000A},
> +	/*1600.000*/ { 160, 0x00001001, 0x0000000A},
> +	/*1237.500*/ { 165, 0x01770C01, 0x0001F407},
> +	/*1487.500*/ { 170, 0x036B0E01, 0x0002EE08},
> +	/*1575.000*/ { 175, 0x02EE0F01, 0x00000009},
> +	/*1575.000*/ { 180, 0x02EE0F01, 0x0002EE08},
> +	/*1387.500*/ { 185, 0x036B0D01, 0x0001F407},
> +	/*1425.000*/ { 190, 0x00FA0E01, 0x0001F407},
> +	/*1462.500*/ { 195, 0x02710E01, 0x0001F407},
> +	/*1600.000*/ { 200, 0x00001001, 0x00000008},
> +	/*1537.500*/ { 205, 0x01770F01, 0x0001F407},
> +	/*1575.000*/ { 210, 0x02EE0F01, 0x0001F407},
> +	/*1075.000*/ { 215, 0x02EE0A01, 0x00000005},
> +	/*1512.500*/ { 220, 0x007D0F01, 0x00036B06},
> +	/*1575.000*/ { 225, 0x02EE0F01, 0x00000007},
> +	/*1437.500*/ { 230, 0x01770E01, 0x0000FA06},
> +	/*1175.000*/ { 235, 0x02EE0B01, 0x00000005},
> +	/*1500.000*/ { 240, 0x00000F01, 0x0000FA06},
> +	/*1225.000*/ { 245, 0x00FA0C01, 0x00000005},
> +	/*1562.500*/ { 250, 0x02710F01, 0x0000FA06},
> +	/*1275.000*/ { 255, 0x02EE0C01, 0x00000005},
> +	/*1462.500*/ { 260, 0x02710E01, 0x00027105},
> +	/*1325.000*/ { 265, 0x00FA0D01, 0x00000005},
> +	/*1350.000*/ { 270, 0x01F40D01, 0x00000005},
> +	/*1512.500*/ { 275, 0x007D0F01, 0x0001F405},
> +	/*1575.000*/ { 280, 0x02EE0F01, 0x00027105},
> +	/*1425.000*/ { 285, 0x00FA0E01, 0x00000005},
> +	/*1450.000*/ { 290, 0x01F40E01, 0x00000005},
> +	/*1475.000*/ { 295, 0x02EE0E01, 0x00000005},
> +	/*1575.000*/ { 300, 0x02EE0F01, 0x0000FA05},
> +	/*1525.000*/ { 305, 0x00FA0F01, 0x00000005},
> +	/*1550.000*/ { 310, 0x01F40F01, 0x00000005},
> +	/*1575.000*/ { 315, 0x02EE0F01, 0x00000005},
> +	/*1600.000*/ { 320, 0x00001001, 0x00000005},
> +	/*1462.500*/ { 325, 0x02710E01, 0x0001F404},
> +	/*1237.500*/ { 330, 0x01770C01, 0x0002EE03},
> +	/* 837.500*/ { 335, 0x01770801, 0x0001F402},
> +	/*1487.500*/ { 340, 0x036B0E01, 0x00017704},
> +	/* 862.500*/ { 345, 0x02710801, 0x0001F402},
> +	/*1575.000*/ { 350, 0x02EE0F01, 0x0001F404},
> +	/* 887.500*/ { 355, 0x036B0801, 0x0001F402},
> +	/*1575.000*/ { 360, 0x02EE0F01, 0x00017704},
> +	/* 912.500*/ { 365, 0x007D0901, 0x0001F402},
> +	/*1387.500*/ { 370, 0x036B0D01, 0x0002EE03},
> +	/*1500.000*/ { 375, 0x00000F01, 0x00000004},
> +	/*1425.000*/ { 380, 0x00FA0E01, 0x0002EE03},
> +	/* 962.500*/ { 385, 0x02710901, 0x0001F402},
> +	/*1462.500*/ { 390, 0x02710E01, 0x0002EE03},
> +	/* 987.500*/ { 395, 0x036B0901, 0x0001F402},
> +	/*1600.000*/ { 400, 0x00001001, 0x00000004},
> +	/*1012.500*/ { 405, 0x007D0A01, 0x0001F402},
> +	/*1537.500*/ { 410, 0x01770F01, 0x0002EE03},
> +	/*1037.500*/ { 415, 0x01770A01, 0x0001F402},
> +	/*1575.000*/ { 420, 0x02EE0F01, 0x0002EE03},
> +	/*1487.500*/ { 425, 0x036B0E01, 0x0001F403},
> +	/*1075.000*/ { 430, 0x02EE0A01, 0x0001F402},
> +	/*1087.500*/ { 435, 0x036B0A01, 0x0001F402},
> +	/*1375.000*/ { 440, 0x02EE0D01, 0x00007D03},
> +	/*1112.500*/ { 445, 0x007D0B01, 0x0001F402},
> +	/*1575.000*/ { 450, 0x02EE0F01, 0x0001F403},
> +	/*1137.500*/ { 455, 0x01770B01, 0x0001F402},
> +	/*1437.500*/ { 460, 0x01770E01, 0x00007D03},
> +	/*1162.500*/ { 465, 0x02710B01, 0x0001F402},
> +	/*1175.000*/ { 470, 0x02EE0B01, 0x0001F402},
> +	/*1425.000*/ { 475, 0x00FA0E01, 0x00000003},
> +	/*1500.000*/ { 480, 0x00000F01, 0x00007D03},
> +	/*1212.500*/ { 485, 0x007D0C01, 0x0001F402},
> +	/*1225.000*/ { 490, 0x00FA0C01, 0x0001F402},
> +	/*1237.500*/ { 495, 0x01770C01, 0x0001F402},
> +	/*1562.500*/ { 500, 0x02710F01, 0x00007D03},
> +	/*1262.500*/ { 505, 0x02710C01, 0x0001F402},
> +	/*1275.000*/ { 510, 0x02EE0C01, 0x0001F402},
> +	/*1287.500*/ { 515, 0x036B0C01, 0x0001F402},
> +	/*1300.000*/ { 520, 0x00000D01, 0x0001F402},
> +	/*1575.000*/ { 525, 0x02EE0F01, 0x00000003},
> +	/*1325.000*/ { 530, 0x00FA0D01, 0x0001F402},
> +	/*1337.500*/ { 535, 0x01770D01, 0x0001F402},
> +	/*1350.000*/ { 540, 0x01F40D01, 0x0001F402},
> +	/*1362.500*/ { 545, 0x02710D01, 0x0001F402},
> +	/*1512.500*/ { 550, 0x007D0F01, 0x0002EE02},
> +	/*1387.500*/ { 555, 0x036B0D01, 0x0001F402},
> +	/*1400.000*/ { 560, 0x00000E01, 0x0001F402},
> +	/*1412.500*/ { 565, 0x007D0E01, 0x0001F402},
> +	/*1425.000*/ { 570, 0x00FA0E01, 0x0001F402},
> +	/*1437.500*/ { 575, 0x01770E01, 0x0001F402},
> +	/*1450.000*/ { 580, 0x01F40E01, 0x0001F402},
> +	/*1462.500*/ { 585, 0x02710E01, 0x0001F402},
> +	/*1475.000*/ { 590, 0x02EE0E01, 0x0001F402},
> +	/*1487.500*/ { 595, 0x036B0E01, 0x0001F402},
> +	/*1575.000*/ { 600, 0x02EE0F01, 0x00027102},
> +	/*1512.500*/ { 605, 0x007D0F01, 0x0001F402},
> +	/*1525.000*/ { 610, 0x00FA0F01, 0x0001F402},
> +	/*1537.500*/ { 615, 0x01770F01, 0x0001F402},
> +	/*1550.000*/ { 620, 0x01F40F01, 0x0001F402},
> +	/*1562.500*/ { 625, 0x02710F01, 0x0001F402},
> +	/*1575.000*/ { 630, 0x02EE0F01, 0x0001F402},
> +	/*1587.500*/ { 635, 0x036B0F01, 0x0001F402},
> +	/*1600.000*/ { 640, 0x00001001, 0x0001F402},
> +	/*1290.000*/ { 645, 0x01F44005, 0x00000002},
> +	/*1462.500*/ { 650, 0x02710E01, 0x0000FA02}
> +};
> +
> +static u32 find_matching_freq_config(unsigned short freq,
> +				     const struct xmgnt_ocl_clockwiz *table,
> +				     int size)
> +{
> +	u32 end = size - 1;
> +	u32 start = 0;
> +	u32 idx;
> +
> +	if (freq < table[0].ocl)
> +		return 0;
> +
> +	if (freq > table[size - 1].ocl)
> +		return size - 1;
> +
> +	while (start < end) {
> +		idx = (start + end) / 2;
> +		if (freq == table[idx].ocl)
> +			break;
> +		if (freq < table[idx].ocl)
> +			end = idx;
> +		else
> +			start = idx + 1;
> +	}
> +	if (freq < table[idx].ocl)
> +		idx--;
> +
> +	return idx;
> +}
> +
> +static u32 find_matching_freq(u32 freq,
> +			      const struct xmgnt_ocl_clockwiz *freq_table,
> +			      int freq_table_size)
> +{
> +	int idx = find_matching_freq_config(freq, freq_table, freq_table_size);
> +
> +	return freq_table[idx].ocl;
> +}
> +
> +static inline int clock_wiz_busy(struct clock *clock, int cycle, int interval)
> +{
> +	u32 val = 0;
> +	int count;
> +	int ret;
> +
> +	for (count = 0; count < cycle; count++) {
> +		ret = regmap_read(clock->regmap, XRT_CLOCK_STATUS_REG, &val);
> +		if (ret) {
> +			CLOCK_ERR(clock, "read status failed %d", ret);
> +			return ret;
> +		}
> +		if (val == 1)
> +			break;
> +
> +		mdelay(interval);
> +	}
> +	if (val != 1) {
> +		CLOCK_ERR(clock, "clockwiz is (%u) busy after %d ms",
> +			  val, cycle * interval);
> +		return -EBUSY;
> +	}
> +
> +	return 0;
> +}
> +
> +static int get_freq(struct clock *clock, u16 *freq)
> +{
> +	u32 mul_frac0 = 0;
> +	u32 div_frac1 = 0;
> +	u32 mul0, div0;
> +	u64 input;
> +	u32 div1;
> +	u32 val;
> +	int ret;
> +
> +	WARN_ON(!mutex_is_locked(&clock->clock_lock));
> +
> +	ret = regmap_read(clock->regmap, XRT_CLOCK_STATUS_REG, &val);
> +	if (ret) {
> +		CLOCK_ERR(clock, "read status failed %d", ret);
> +		return ret;
> +	}
> +
> +	if ((val & 0x1) == 0) {
> +		CLOCK_ERR(clock, "clockwiz is busy %x", val);
> +		*freq = 0;
> +		return -EBUSY;
> +	}
> +
> +	ret = regmap_read(clock->regmap, XRT_CLOCK_CLKFBOUT_REG, &val);
> +	if (ret) {
> +		CLOCK_ERR(clock, "read clkfbout failed %d", ret);
> +		return ret;
> +	}
> +
> +	div0 = val & 0xff;
> +	mul0 = (val & 0xff00) >> 8;
> +	if (val & BIT(26)) {
> +		mul_frac0 = val >> 16;
> +		mul_frac0 &= 0x3ff;
> +	}
> +
> +	/*
> +	 * Multiply both numerator (mul0) and the denominator (div0) with 1000
> +	 * to account for fractional portion of multiplier
> +	 */
> +	mul0 *= 1000;
> +	mul0 += mul_frac0;
> +	div0 *= 1000;
> +
> +	ret = regmap_read(clock->regmap, XRT_CLOCK_CLKOUT0_REG, &val);
> +	if (ret) {
> +		CLOCK_ERR(clock, "read clkout0 failed %d", ret);
> +		return ret;
> +	}
> +
> +	div1 = val & 0xff;
> +	if (val & BIT(18)) {
> +		div_frac1 = val >> 8;
> +		div_frac1 &= 0x3ff;
> +	}
> +
> +	/*
> +	 * Multiply both numerator (mul0) and the denominator (div1) with
> +	 * 1000 to account for fractional portion of divider
> +	 */
> +
> +	div1 *= 1000;
> +	div1 += div_frac1;
> +	div0 *= div1;
> +	mul0 *= 1000;
> +	if (div0 == 0) {
> +		CLOCK_ERR(clock, "clockwiz 0 divider");
> +		return 0;
> +	}
> +
> +	input = mul0 * 100;
> +	do_div(input, div0);
> +	*freq = (u16)input;
> +
> +	return 0;
> +}
> +
> +static int set_freq(struct clock *clock, u16 freq)
> +{
> +	int err = 0;
> +	u32 idx = 0;
> +	u32 val = 0;
> +	u32 config;
> +
> +	mutex_lock(&clock->clock_lock);
> +	idx = find_matching_freq_config(freq, frequency_table,
> +					ARRAY_SIZE(frequency_table));
> +
> +	CLOCK_INFO(clock, "New: %d Mhz", freq);
> +	err = clock_wiz_busy(clock, 20, 50);
> +	if (err)
> +		goto fail;
> +
> +	config = frequency_table[idx].config0;
> +	err = regmap_write(clock->regmap, XRT_CLOCK_CLKFBOUT_REG, config);
> +	if (err) {
> +		CLOCK_ERR(clock, "write clkfbout failed %d", err);
> +		goto fail;
> +	}
> +
> +	config = frequency_table[idx].config2;
> +	err = regmap_write(clock->regmap, XRT_CLOCK_CLKOUT0_REG, config);
> +	if (err) {
> +		CLOCK_ERR(clock, "write clkout0 failed %d", err);
> +		goto fail;
> +	}
> +
> +	mdelay(10);
> +	err = regmap_write(clock->regmap, XRT_CLOCK_LOAD_SADDR_SEN_REG, 7);
> +	if (err) {
> +		CLOCK_ERR(clock, "write load_saddr_sen failed %d", err);
> +		goto fail;
> +	}
> +
> +	mdelay(1);
> +	err = regmap_write(clock->regmap, XRT_CLOCK_LOAD_SADDR_SEN_REG, 2);
> +	if (err) {
> +		CLOCK_ERR(clock, "write saddr failed %d", err);
> +		goto fail;
> +	}
> +
> +	CLOCK_INFO(clock, "clockwiz waiting for locked signal");
> +
> +	err = clock_wiz_busy(clock, 100, 100);
> +	if (err) {
> +		CLOCK_ERR(clock, "clockwiz MMCM/PLL did not lock");
> +		/* restore */
> +		regmap_write(clock->regmap, XRT_CLOCK_LOAD_SADDR_SEN_REG, 4);
> +		mdelay(10);
> +		regmap_write(clock->regmap, XRT_CLOCK_LOAD_SADDR_SEN_REG, 0);
> +		goto fail;
> +	}
> +	regmap_read(clock->regmap, XRT_CLOCK_CLKFBOUT_REG, &val);
> +	CLOCK_INFO(clock, "clockwiz CONFIG(0) 0x%x", val);
> +	regmap_read(clock->regmap, XRT_CLOCK_CLKOUT0_REG, &val);
> +	CLOCK_INFO(clock, "clockwiz CONFIG(2) 0x%x", val);
> +
> +fail:
> +	mutex_unlock(&clock->clock_lock);
> +	return err;
> +}
> +
> +static int get_freq_counter(struct clock *clock, u32 *freq)
> +{
> +	struct xrt_subdev_platdata *pdata = DEV_PDATA(clock->xdev);
> +	struct xrt_device *xdev = clock->xdev;
> +	struct xrt_device *counter_leaf;
> +	const void *counter;
> +	int err;
> +
> +	WARN_ON(!mutex_is_locked(&clock->clock_lock));
> +
> +	err = xrt_md_get_prop(DEV(xdev), pdata->xsp_dtb, clock->clock_ep_name,
> +			      NULL, XRT_MD_PROP_CLK_CNT, &counter, NULL);
> +	if (err) {
> +		xrt_err(xdev, "no counter specified");
> +		return err;
> +	}
> +
> +	counter_leaf = xleaf_get_leaf_by_epname(xdev, counter);
> +	if (!counter_leaf) {
> +		xrt_err(xdev, "can't find counter");
> +		return -ENOENT;
> +	}
> +
> +	err = xleaf_call(counter_leaf, XRT_CLKFREQ_READ, freq);
> +	if (err)
> +		xrt_err(xdev, "can't read counter");
> +	xleaf_put_leaf(clock->xdev, counter_leaf);
> +
> +	return err;
> +}
> +
> +static int clock_get_freq(struct clock *clock, u16 *freq, u32 *freq_cnter)
> +{
> +	int err = 0;
> +
> +	mutex_lock(&clock->clock_lock);
> +
> +	if (err == 0 && freq)
> +		err = get_freq(clock, freq);
> +
> +	if (err == 0 && freq_cnter)
> +		err = get_freq_counter(clock, freq_cnter);
> +
> +	mutex_unlock(&clock->clock_lock);
> +	return err;
> +}
> +
> +static int clock_verify_freq(struct clock *clock)
> +{
> +	u32 lookup_freq, clock_freq_counter, request_in_khz, tolerance;
> +	int err = 0;
> +	u16 freq;
> +
> +	mutex_lock(&clock->clock_lock);
> +
> +	err = get_freq(clock, &freq);
> +	if (err) {
> +		xrt_err(clock->xdev, "get freq failed, %d", err);
> +		goto end;
> +	}
> +
> +	err = get_freq_counter(clock, &clock_freq_counter);
> +	if (err) {
> +		xrt_err(clock->xdev, "get freq counter failed, %d", err);
> +		goto end;
> +	}
> +
> +	lookup_freq = find_matching_freq(freq, frequency_table,
> +					 ARRAY_SIZE(frequency_table));
> +	request_in_khz = lookup_freq * 1000;
> +	tolerance = lookup_freq * 50;
> +	if (tolerance < abs(clock_freq_counter - request_in_khz)) {
> +		CLOCK_ERR(clock,
> +			  "set clock(%s) failed, request %ukhz, actual %dkhz",
> +			  clock->clock_ep_name, request_in_khz, clock_freq_counter);
> +		err = -EDOM;
> +	} else {
> +		CLOCK_INFO(clock, "verified clock (%s)", clock->clock_ep_name);
> +	}
> +
> +end:
> +	mutex_unlock(&clock->clock_lock);
> +	return err;
> +}
> +
> +static int clock_init(struct clock *clock)
> +{
> +	struct xrt_subdev_platdata *pdata = DEV_PDATA(clock->xdev);
> +	const u16 *freq;
> +	int err = 0;
> +
> +	err = xrt_md_get_prop(DEV(clock->xdev), pdata->xsp_dtb,
> +			      clock->clock_ep_name, NULL, XRT_MD_PROP_CLK_FREQ,
> +		(const void **)&freq, NULL);
> +	if (err) {
> +		xrt_info(clock->xdev, "no default freq");
> +		return 0;
> +	}
> +
> +	err = set_freq(clock, be16_to_cpu(*freq));
> +
> +	return err;
> +}
> +
> +static ssize_t freq_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct clock *clock = xrt_get_drvdata(to_xrt_dev(dev));
> +	ssize_t count;
> +	u16 freq = 0;
> +
> +	count = clock_get_freq(clock, &freq, NULL);
> +	if (count < 0)
> +		return count;
> +
> +	count = snprintf(buf, 64, "%u\n", freq);
> +
> +	return count;
> +}
> +static DEVICE_ATTR_RO(freq);
> +
> +static struct attribute *clock_attrs[] = {
> +	&dev_attr_freq.attr,
> +	NULL,
> +};
> +
> +static struct attribute_group clock_attr_group = {
> +	.attrs = clock_attrs,
> +};
> +
> +static int
> +xrt_clock_leaf_call(struct xrt_device *xdev, u32 cmd, void *arg)
> +{
> +	struct clock *clock;
> +	int ret = 0;
> +
> +	clock = xrt_get_drvdata(xdev);
> +
> +	switch (cmd) {
> +	case XRT_XLEAF_EVENT:
> +		/* Does not handle any event. */
> +		break;
> +	case XRT_CLOCK_SET: {
> +		u16	freq = (u16)(uintptr_t)arg;
> +
> +		ret = set_freq(clock, freq);
> +		break;
> +	}
> +	case XRT_CLOCK_VERIFY:
> +		ret = clock_verify_freq(clock);
> +		break;
> +	case XRT_CLOCK_GET: {
> +		struct xrt_clock_get *get =
> +			(struct xrt_clock_get *)arg;
> +
> +		ret = clock_get_freq(clock, &get->freq, &get->freq_cnter);
> +		break;
> +	}
> +	default:
> +		xrt_err(xdev, "unsupported cmd %d", cmd);
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static void clock_remove(struct xrt_device *xdev)
> +{
> +	sysfs_remove_group(&xdev->dev.kobj, &clock_attr_group);
> +}
> +
> +static int clock_probe(struct xrt_device *xdev)
> +{
> +	struct clock *clock = NULL;
> +	void __iomem *base = NULL;
> +	struct resource *res;
> +	int ret;
> +
> +	clock = devm_kzalloc(&xdev->dev, sizeof(*clock), GFP_KERNEL);
> +	if (!clock)
> +		return -ENOMEM;
> +
> +	xrt_set_drvdata(xdev, clock);
> +	clock->xdev = xdev;
> +	mutex_init(&clock->clock_lock);
> +
> +	res = xrt_get_resource(xdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		ret = -EINVAL;
> +		goto failed;
> +	}
> +
> +	base = devm_ioremap_resource(&xdev->dev, res);
> +	if (IS_ERR(base)) {
> +		ret = PTR_ERR(base);
> +		goto failed;
> +	}
> +
> +	clock->regmap = devm_regmap_init_mmio(&xdev->dev, base, &clock_regmap_config);
> +	if (IS_ERR(clock->regmap)) {
> +		CLOCK_ERR(clock, "regmap %pR failed", res);
> +		ret = PTR_ERR(clock->regmap);
> +		goto failed;
> +	}
> +	clock->clock_ep_name = res->name;
> +
> +	ret = clock_init(clock);
> +	if (ret)
> +		goto failed;
> +
> +	ret = sysfs_create_group(&xdev->dev.kobj, &clock_attr_group);
> +	if (ret) {
> +		CLOCK_ERR(clock, "create clock attrs failed: %d", ret);
> +		goto failed;
> +	}
> +
> +	CLOCK_INFO(clock, "successfully initialized Clock subdev");
> +
> +	return 0;
> +
> +failed:
> +	return ret;
> +}
> +
> +static struct xrt_dev_endpoints xrt_clock_endpoints[] = {
> +	{
> +		.xse_names = (struct xrt_dev_ep_names[]) {
> +			{ .compat = "clkwiz" },
> +			{ NULL },
> +		},
> +		.xse_min_ep = 1,
> +	},
> +	{ 0 },
> +};
> +
> +static struct xrt_driver xrt_clock_driver = {
> +	.driver = {
> +		.name = XRT_CLOCK,
> +	},
> +	.subdev_id = XRT_SUBDEV_CLOCK,
> +	.endpoints = xrt_clock_endpoints,
> +	.probe = clock_probe,
> +	.remove = clock_remove,
> +	.leaf_call = xrt_clock_leaf_call,
> +};
> +
> +XRT_LEAF_INIT_FINI_FUNC(clock);

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