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Message-ID: <augqwu7iv42ges4x53ysulbfv43x6hadku7rgwjlscelsx5iwk@xmpeutszvjev>
Date: Fri, 22 Nov 2024 03:42:09 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Yongbang Shi <shiyongbang@...wei.com>
Cc: xinliang.liu@...aro.org, tiantao6@...ilicon.com,
maarten.lankhorst@...ux.intel.com, mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com,
daniel@...ll.ch, kong.kongxinwei@...ilicon.com, liangjian010@...wei.com,
chenjianmin@...wei.com, lidongming5@...wei.com, libaihan@...wei.com,
shenjian15@...wei.com, shaojijie@...wei.com, dri-devel@...ts.freedesktop.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 drm-dp 1/5] drm/hisilicon/hibmc: add dp aux in hibmc
On Mon, Nov 18, 2024 at 10:28:01PM +0800, Yongbang Shi wrote:
> From: baihan li <libaihan@...wei.com>
>
> Add dp aux read/write functions. They are basic functions
> and will be used later.
>
> Signed-off-by: Baihan Li <libaihan@...wei.com>
> Signed-off-by: Yongbang Shi <shiyongbang@...wei.com>
> ---
> ChangeLog:
> v4 -> v5:
> - fixing build errors reported by kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202411131438.RZWYrWTE-lkp@intel.com/
> v3 -> v4:
> - retun error codes in result incorrect branch, suggested by Dmitry Baryshkov.
> - replacing all ret= with returns, suggested by Dmitry Baryshkov.
> - moving the comment below the judgment statement, suggested by Dmitry Baryshkov.
> - moving definations to the source file and clearing headers, suggested by Dmitry Baryshkov.
> - reanaming dp_prefix to hibmc_dp_prefix, suggested by Dmitry Baryshkov.
> - changing hibmc_dp_reg_write_field to static inline and lock, suggested by Dmitry Baryshkov.
> - moving some structs to later patch, suggested by Dmitry Baryshkov.
> v2 -> v3:
> - put the macro definations in latter patch where they are actually used, suggested by Dmitry Baryshkov.
> - rename some macro definations to make them sensible, suggested by Dmitry Baryshkov.
> - using FIELD_PREP and FIELD_GET, suggested by Dmitry Baryshkov.
> - using DP_DPCD_REV_foo, suggested by Dmitry Baryshkov.
> - fix build errors reported by kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202410250305.UHKDhtxy-lkp@intel.com/
> v1 -> v2:
> - using drm_dp_aux frame implement dp aux read and write functions, suggested by Jani Nikula.
> - using drm dp header files' dp macros instead, suggested by Andy Yan.
> v1:https://lore.kernel.org/all/20240930100610.782363-1-shiyongbang@huawei.com/
> ---
> drivers/gpu/drm/hisilicon/hibmc/Makefile | 3 +-
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c | 164 +++++++++++++++++++
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h | 38 +++++
> drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h | 27 +++
> 4 files changed, 231 insertions(+), 1 deletion(-)
> create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
> create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
> create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
>
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/Makefile b/drivers/gpu/drm/hisilicon/hibmc/Makefile
> index d25c75e60d3d..8770ec6dfffd 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/Makefile
> +++ b/drivers/gpu/drm/hisilicon/hibmc/Makefile
> @@ -1,4 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0-only
> -hibmc-drm-y := hibmc_drm_drv.o hibmc_drm_de.o hibmc_drm_vdac.o hibmc_drm_i2c.o
> +hibmc-drm-y := hibmc_drm_drv.o hibmc_drm_de.o hibmc_drm_vdac.o hibmc_drm_i2c.o \
> + dp/dp_aux.o
>
> obj-$(CONFIG_DRM_HISI_HIBMC) += hibmc-drm.o
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
> new file mode 100644
> index 000000000000..16bdfefbf255
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
> @@ -0,0 +1,164 @@
> +// SPDX-License-Identifier: GPL-2.0-or-laterHIBMC_BYTES_IN_U32
> +// Copyright (c) 2024 Hisilicon Limited.
> +
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/minmax.h>
> +#include <drm/drm_device.h>
> +#include <drm/drm_print.h>
> +#include "dp_comm.h"
> +#include "dp_reg.h"
> +
> +#define HIBMC_AUX_CMD_REQ_LEN GENMASK(7, 4)
> +#define HIBMC_AUX_CMD_ADDR GENMASK(27, 8)
> +#define HIBMC_AUX_CMD_I2C_ADDR_ONLY BIT(28)
> +#define HIBMC_BYTES_IN_U32 4
> +#define HIBMC_AUX_I2C_WRITE_SUCCESS 0x1
> +#define HIBMC_DP_MIN_PULSE_NUM 0x9
> +#define BITS_IN_U8 8
> +
> +static inline void hibmc_dp_aux_reset(struct hibmc_dp_dev *dp)
> +{
> + hibmc_dp_reg_write_field(dp, HIBMC_DP_DPTX_RST_CTRL, HIBMC_DP_CFG_AUX_RST_N, 0x0);
> + usleep_range(10, 15);
> + hibmc_dp_reg_write_field(dp, HIBMC_DP_DPTX_RST_CTRL, HIBMC_DP_CFG_AUX_RST_N, 0x1);
> +}
> +
> +static void hibmc_dp_aux_read_data(struct hibmc_dp_dev *dp, u8 *buf, u8 size)
> +{
> + u32 reg_num;
> + u32 value;
> + u32 num;
> + u8 i, j;
> +
> + reg_num = DIV_ROUND_UP(size, HIBMC_BYTES_IN_U32);
> + for (i = 0; i < reg_num; i++) {
> + /* number of bytes read from a single register */
> + num = min(size - i * HIBMC_BYTES_IN_U32, HIBMC_BYTES_IN_U32);
> + value = readl(dp->base + HIBMC_DP_AUX_RD_DATA0 + i * HIBMC_BYTES_IN_U32);
> + /* convert the 32-bit value of the register to the buffer. */
> + for (j = 0; j < num; j++)
> + buf[i * HIBMC_BYTES_IN_U32 + j] = value >> (j * BITS_IN_U8);
> + }
> +}
> +
> +static void hibmc_dp_aux_write_data(struct hibmc_dp_dev *dp, u8 *buf, u8 size)
> +{
> + u32 reg_num;
> + u32 value;
> + u32 num;
> + u8 i, j;
> +
> + reg_num = DIV_ROUND_UP(size, HIBMC_BYTES_IN_U32);
> + for (i = 0; i < reg_num; i++) {
> + /* number of bytes written to a single register */
> + num = min_t(u8, size - i * HIBMC_BYTES_IN_U32, HIBMC_BYTES_IN_U32);
> + value = 0;
> + /* obtain the 32-bit value written to a single register. */
> + for (j = 0; j < num; j++)
> + value |= buf[i * HIBMC_BYTES_IN_U32 + j] << (j * BITS_IN_U8);
> + /* writing data to a single register */
> + writel(value, dp->base + HIBMC_DP_AUX_WR_DATA0 + i * HIBMC_BYTES_IN_U32);
> + }
> +}
> +
> +static u32 hibmc_dp_aux_build_cmd(const struct drm_dp_aux_msg *msg)
> +{
> + u32 aux_cmd = msg->request;
> +
> + if (msg->size)
> + aux_cmd |= FIELD_PREP(HIBMC_AUX_CMD_REQ_LEN, (msg->size - 1));
> + else
> + aux_cmd |= FIELD_PREP(HIBMC_AUX_CMD_I2C_ADDR_ONLY, 1);
> +
> + aux_cmd |= FIELD_PREP(HIBMC_AUX_CMD_ADDR, msg->address);
> +
> + return aux_cmd;
> +}
> +
> +/* ret >= 0, ret is size; ret < 0, ret is err code */
> +static int hibmc_dp_aux_parse_xfer(struct hibmc_dp_dev *dp, struct drm_dp_aux_msg *msg)
> +{
> + u32 buf_data_cnt;
> + u32 aux_status;
> +
> + aux_status = readl(dp->base + HIBMC_DP_AUX_STATUS);
> + msg->reply = FIELD_GET(HIBMC_DP_CFG_AUX_STATUS, aux_status);
> +
> + if (aux_status & HIBMC_DP_CFG_AUX_TIMEOUT)
> + return -ETIMEDOUT;
> +
> + /* only address */
> + if (!msg->size)
> + return 0;
> +
> + if (msg->reply != DP_AUX_NATIVE_REPLY_ACK)
> + return -EIO;
> +
> + buf_data_cnt = FIELD_GET(HIBMC_DP_CFG_AUX_READY_DATA_BYTE, aux_status);
> +
> + switch (msg->request) {
> + case DP_AUX_NATIVE_WRITE:
> + return msg->size;
> + case DP_AUX_I2C_WRITE | DP_AUX_I2C_MOT:
> + if (buf_data_cnt == HIBMC_AUX_I2C_WRITE_SUCCESS)
> + return msg->size;
> + else
> + return FIELD_GET(HIBMC_DP_CFG_AUX, aux_status);
> + case DP_AUX_NATIVE_READ:
> + case DP_AUX_I2C_READ | DP_AUX_I2C_MOT:
> + buf_data_cnt--;
> + if (buf_data_cnt != msg->size) {
> + /* only the successful part of data is read */
> + return -EBUSY;
> + }
> +
> + /* all data is successfully read */
> + hibmc_dp_aux_read_data(dp, msg->buffer, msg->size);
> + return msg->size;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +/* ret >= 0 ,ret is size; ret < 0, ret is err code */
> +static ssize_t hibmc_dp_aux_xfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
> +{
> + struct hibmc_dp_dev *dp = container_of(aux, struct hibmc_dp_dev, aux);
> + u32 aux_cmd;
> + int ret;
> + u32 val; /* val will be assigned at the beginning of readl_poll_timeout function */
> +
> + writel(0, dp->base + HIBMC_DP_AUX_WR_DATA0);
> + writel(0, dp->base + HIBMC_DP_AUX_WR_DATA1);
> + writel(0, dp->base + HIBMC_DP_AUX_WR_DATA2);
> + writel(0, dp->base + HIBMC_DP_AUX_WR_DATA3);
> +
> + hibmc_dp_aux_write_data(dp, msg->buffer, msg->size);
> +
> + aux_cmd = hibmc_dp_aux_build_cmd(msg);
> + writel(aux_cmd, dp->base + HIBMC_DP_AUX_CMD_ADDR);
> +
> + /* enable aux transfer */
> + hibmc_dp_reg_write_field(dp, HIBMC_DP_AUX_REQ, HIBMC_DP_CFG_AUX_REQ, 0x1);
> + ret = readl_poll_timeout(dp->base + HIBMC_DP_AUX_REQ, val,
> + !(val & HIBMC_DP_CFG_AUX_REQ), 50, 5000);
> + if (ret) {
> + hibmc_dp_aux_reset(dp);
> + return ret;
> + }
> +
> + return hibmc_dp_aux_parse_xfer(dp, msg);
> +}
> +
> +void hibmc_dp_aux_init(struct hibmc_dp_dev *dp)
> +{
> + hibmc_dp_reg_write_field(dp, HIBMC_DP_AUX_REQ, HIBMC_DP_CFG_AUX_SYNC_LEN_SEL, 0x0);
> + hibmc_dp_reg_write_field(dp, HIBMC_DP_AUX_REQ, HIBMC_DP_CFG_AUX_TIMER_TIMEOUT, 0x1);
> + hibmc_dp_reg_write_field(dp, HIBMC_DP_AUX_REQ, HIBMC_DP_CFG_AUX_MIN_PULSE_NUM,
> + HIBMC_DP_MIN_PULSE_NUM);
> +
> + dp->aux.transfer = hibmc_dp_aux_xfer;
> + dp->aux.is_remote = 0;
> + drm_dp_aux_init(&dp->aux);
> +}
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
> new file mode 100644
> index 000000000000..ce3b6fa4ea9e
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
> @@ -0,0 +1,38 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright (c) 2024 Hisilicon Limited. */
> +
> +#ifndef DP_COMM_H
> +#define DP_COMM_H
> +
> +#include <linux/types.h>
> +#include <linux/bitops.h>
> +#include <linux/errno.h>
> +#include <linux/mutex.h>
> +#include <linux/kernel.h>
> +#include <linux/bitfield.h>
> +#include <linux/io.h>
> +#include <drm/display/drm_dp_helper.h>
> +
> +struct hibmc_dp_dev {
> + struct drm_dp_aux aux;
> + struct drm_device *dev;
> + void __iomem *base;
> + struct mutex lock; /* protects concurrent RW in hibmc_dp_reg_write_field() */
> +};
> +
> +#define dp_field_modify(reg_value, mask, val) ({ \
> + (reg_value) &= ~(mask); \
> + (reg_value) |= FIELD_PREP(mask, val); })
do { ... } while (0) or static inline. Or just inline into the calling
function, if there is just one place where it is used.
> +
> +#define hibmc_dp_reg_write_field(dp, offset, mask, val) ({ \
> + typeof(dp) _dp = dp; \
> + typeof(_dp->base) addr = (_dp->base + (offset)); \
> + mutex_lock(&_dp->lock); \
> + u32 reg_value = readl(addr); \
> + dp_field_modify(reg_value, mask, val); \
> + writel(reg_value, addr); \
> + mutex_unlock(&_dp->lock); })
I'd prefer a static inline function. Other than that:
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> +
> +void hibmc_dp_aux_init(struct hibmc_dp_dev *dp);
> +
> +#endif
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
> new file mode 100644
> index 000000000000..f3e6781e111a
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h
> @@ -0,0 +1,27 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright (c) 2024 Hisilicon Limited. */
> +
> +#ifndef DP_REG_H
> +#define DP_REG_H
> +
> +#define HIBMC_DP_AUX_CMD_ADDR 0x50
> +#define HIBMC_DP_AUX_WR_DATA0 0x54
> +#define HIBMC_DP_AUX_WR_DATA1 0x58
> +#define HIBMC_DP_AUX_WR_DATA2 0x5c
> +#define HIBMC_DP_AUX_WR_DATA3 0x60
> +#define HIBMC_DP_AUX_RD_DATA0 0x64
> +#define HIBMC_DP_AUX_REQ 0x74
> +#define HIBMC_DP_AUX_STATUS 0x78
> +#define HIBMC_DP_DPTX_RST_CTRL 0x700
> +
> +#define HIBMC_DP_CFG_AUX_SYNC_LEN_SEL BIT(1)
> +#define HIBMC_DP_CFG_AUX_TIMER_TIMEOUT BIT(2)
> +#define HIBMC_DP_CFG_AUX_MIN_PULSE_NUM GENMASK(13, 9)
> +#define HIBMC_DP_CFG_AUX_REQ BIT(0)
> +#define HIBMC_DP_CFG_AUX_RST_N BIT(4)
> +#define HIBMC_DP_CFG_AUX_TIMEOUT BIT(0)
> +#define HIBMC_DP_CFG_AUX_READY_DATA_BYTE GENMASK(16, 12)
> +#define HIBMC_DP_CFG_AUX GENMASK(24, 17)
> +#define HIBMC_DP_CFG_AUX_STATUS GENMASK(11, 4)
> +
> +#endif
> --
> 2.33.0
>
--
With best wishes
Dmitry
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