On Fri, Nov 01, 2024 at 06:50:25PM +0800, Yongbang Shi wrote:
> From: baihan li <libai...@huawei.com>
> 
> Add dp aux read/write functions. They are basic functions
> and will be used later.
> 
> Signed-off-by: baihan li <libai...@huawei.com>
> Signed-off-by: yongbang shi <shiyongb...@huawei.com>

Is this a proper capitalization of your names? Usually the first letter
of each of them is capital.

> ---
> ChangeLog:
> 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 <l...@intel.com>
>     Closes: 
> https://lore.kernel.org/oe-kbuild-all/202410250305.uhkdhtxy-...@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-shiyongb...@huawei.com/
> ---
>  drivers/gpu/drm/hisilicon/hibmc/Makefile      |   3 +-
>  drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c   | 162 ++++++++++++++++++
>  drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.h   |  23 +++
>  drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h  |  58 +++++++
>  .../gpu/drm/hisilicon/hibmc/dp/dp_config.h    |  19 ++
>  drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h   |  27 +++
>  6 files changed, 291 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_aux.h
>  create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
>  create mode 100644 drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.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..49ecda672109
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c
> @@ -0,0 +1,162 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +// 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"
> +#include "dp_aux.h"
> +
> +#define DP_MIN_PULSE_NUM 0x9
> +
> +static void hibmc_dp_aux_reset(const struct dp_dev *dp)
> +{
> +     dp_reg_write_field(dp->base + DP_DPTX_RST_CTRL, DP_CFG_AUX_RST_N, 0x0);
> +     usleep_range(10, 15);
> +     dp_reg_write_field(dp->base + DP_DPTX_RST_CTRL, DP_CFG_AUX_RST_N, 0x1);
> +}
> +
> +static void hibmc_dp_aux_read_data(struct dp_dev *dp, u8 *buf, u8 size)
> +{
> +     u32 reg_num;
> +     u32 value;
> +     u32 num;
> +     u8 i, j;
> +
> +     reg_num = DIV_ROUND_UP(size, BYTES_IN_U32);
> +     for (i = 0; i < reg_num; i++) {
> +             /* number of bytes read from a single register */
> +             num = min(size - i * BYTES_IN_U32, BYTES_IN_U32);
> +             value = readl(dp->base + DP_AUX_RD_DATA0 + i * BYTES_IN_U32);
> +             /* convert the 32-bit value of the register to the buffer. */
> +             for (j = 0; j < num; j++)
> +                     buf[i * BYTES_IN_U32 + j] = value >> (j * BITS_IN_U8);

put_unaligned_le32()

> +     }
> +}
> +
> +static void hibmc_dp_aux_write_data(struct dp_dev *dp, u8 *buf, u8 size)
> +{
> +     u32 reg_num;
> +     u32 value;
> +     u8 i, j;
> +     u32 num;
> +
> +     reg_num = DIV_ROUND_UP(size, BYTES_IN_U32);
> +     for (i = 0; i < reg_num; i++) {
> +             /* number of bytes written to a single register */
> +             num = min_t(u8, size - i * BYTES_IN_U32, BYTES_IN_U32);
> +             value = 0;
> +             /* obtain the 32-bit value written to a single register. */
> +             for (j = 0; j < num; j++)
> +                     value |= buf[i * BYTES_IN_U32 + j] << (j * BITS_IN_U8);

get_unaligned_le32()

> +             /* writing data to a single register */
> +             writel(value, dp->base + DP_AUX_WR_DATA0 + i * 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(AUX_CMD_REQ_LEN, (msg->size - 1));
> +     else
> +             aux_cmd |= FIELD_PREP(AUX_CMD_I2C_ADDR_ONLY, 1);
> +
> +     aux_cmd |= FIELD_PREP(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 dp_dev *dp, struct drm_dp_aux_msg 
> *msg)
> +{
> +     u32 buf_data_cnt;
> +     u32 aux_status;
> +     int ret = 0;
> +
> +     aux_status = readl(dp->base + DP_AUX_STATUS);
> +     msg->reply = FIELD_GET(DP_CFG_AUX_STATUS, aux_status);
> +
> +     if (aux_status & DP_CFG_AUX_TIMEOUT)
> +             return -ETIMEDOUT;
> +
> +     /* only address */
> +     if (!msg->size)
> +             return 0;
> +
> +     if (msg->reply != DP_AUX_NATIVE_REPLY_ACK)
> +             return 0;

Should this be an error instead?

> +
> +     buf_data_cnt = FIELD_GET(DP_CFG_AUX_READY_DATA_BYTE, aux_status);
> +
> +     switch (msg->request) {
> +     case DP_AUX_NATIVE_WRITE:
> +             ret = msg->size;
> +             break;
> +     case DP_AUX_I2C_WRITE | DP_AUX_I2C_MOT:
> +             if (buf_data_cnt == AUX_I2C_WRITE_SUCCESS)
> +                     ret = msg->size;
> +             else if (buf_data_cnt == AUX_I2C_WRITE_PARTIAL_SUCCESS)
> +                     ret = FIELD_GET(DP_CFG_AUX, aux_status);

Replace all ret= with returns. Nothing happens after the switch-case, so
return right away.

> +             break;
> +     case DP_AUX_NATIVE_READ:
> +     case DP_AUX_I2C_READ | DP_AUX_I2C_MOT:
> +             buf_data_cnt--;
> +             /* only the successful part of data is read */

Nit: only a part of data wass read successfully.
move the comment into the underlying `

> +             if (buf_data_cnt != msg->size) {
> +                     ret = -EBUSY;
> +             } else { /* all data is successfully read */
> +                     hibmc_dp_aux_read_data(dp, msg->buffer, msg->size);
> +                     ret = msg->size;
> +             }
> +             break;
> +     default:
> +             return -EINVAL;
> +     }
> +
> +     return ret;
> +}
> +
> +/* 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 dp_dev *dp = container_of(aux, struct 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 + DP_AUX_WR_DATA0);
> +     writel(0, dp->base + DP_AUX_WR_DATA1);
> +     writel(0, dp->base + DP_AUX_WR_DATA2);
> +     writel(0, dp->base + 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 + DP_AUX_CMD_ADDR);
> +
> +     /* enable aux transfer */
> +     dp_reg_write_field(dp->base + DP_AUX_REQ, DP_CFG_AUX_REQ, 0x1);
> +     ret = readl_poll_timeout(dp->base + DP_AUX_REQ, val, !(val & 
> 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 dp_dev *dp)
> +{
> +     dp_reg_write_field(dp->base + DP_AUX_REQ, DP_CFG_AUX_SYNC_LEN_SEL, 0x0);
> +     dp_reg_write_field(dp->base + DP_AUX_REQ, DP_CFG_AUX_TIMER_TIMEOUT, 
> 0x1);
> +     dp_reg_write_field(dp->base + DP_AUX_REQ, DP_CFG_AUX_MIN_PULSE_NUM, 
> 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_aux.h 
> b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.h
> new file mode 100644
> index 000000000000..794bb0482ea7
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright (c) 2024 Hisilicon Limited. */
> +
> +#ifndef DP_AUX_H
> +#define DP_AUX_H
> +
> +#include <linux/bitops.h>
> +#include "dp_comm.h"
> +
> +#define AUX_I2C_WRITE_SUCCESS                0x1

Move to the source file

> +#define AUX_I2C_WRITE_PARTIAL_SUCCESS        0x2

Ditto

> +#define EQ_MAX_RETRY                 5

Unused

> +#define BYTES_IN_U32                 4


> +#define BITS_IN_U8                   8

This one will go away after using foo_unaligned_le32

> +
> +/* aux_cmd_addr register shift */
> +#define AUX_CMD_REQ_LEN                      GENMASK(7, 4)
> +#define AUX_CMD_ADDR                 GENMASK(27, 8)
> +#define AUX_CMD_I2C_ADDR_ONLY                BIT(28)

These can go to the source file too. Or to dp_reg.h. Don't spawn that
all over the place.

> +
> +void hibmc_dp_aux_init(struct dp_dev *dp);

As the header becomes nearly empty, merge the remnants to a generic
header.

> +
> +#endif
> 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..61a59fd59962
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
> @@ -0,0 +1,58 @@
> +/* 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>
> +
> +#define dp_reg_read_field(addr, mask)                                \

These are still using dp_ prefix. Also using static inline functions
might be easier to handle.

> +             FIELD_GET(mask, readl(addr))
> +
> +#define dp_field_modify(reg_value, mask, value) ({           \
> +             (reg_value) &= ~(mask);                         \
> +             (reg_value) |= FIELD_PREP(mask, value); })
> +
> +#define dp_reg_write_field(addr, mask, val) ({                       \
> +             typeof(addr) _addr = (addr);                    \
> +             u32 _value = readl(_addr);                      \
> +             dp_field_modify(_value, mask, val);             \
> +             writel(_value, _addr); })

I'm still very unsatisfied here. You have an RMW code with no locking.
If anything writes to the same location at the same time, the driver is
busted.

> +
> +struct link_status {

It is hibmc-specific, so please prefix accordingly.

> +     bool clock_recovered;
> +     bool channel_equalized;
> +     u8 cr_done_lanes;
> +};
> +
> +struct link_cap {
> +     int rx_dpcd_revision;
> +     u8 link_rate;
> +     u8 lanes;
> +     bool is_tps3;
> +     bool is_tps4;
> +};
> +
> +struct hibmc_dp_link {
> +     struct link_status status;
> +     u8 *train_set;
> +     struct link_cap cap;
> +};

Please don't define the structures/fields that are not used by the
patch. Introduce them when required.

> +
> +struct dp_dev {
> +     struct hibmc_dp_link link;
> +     struct drm_dp_aux aux;
> +     struct drm_device *dev;
> +     void __iomem *base;
> +     u8 dpcd[DP_RECEIVER_CAP_SIZE];
> +};
> +
> +#endif
> diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.h 
> b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.h
> new file mode 100644
> index 000000000000..0b965e6ba7b3
> --- /dev/null
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_config.h
> @@ -0,0 +1,19 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/* Copyright (c) 2024 Hisilicon Limited. */
> +
> +#ifndef DP_CONFIG_H
> +#define DP_CONFIG_H
> +
> +#define DP_BPP                       24
> +#define DP_SYMBOL_PER_FCLK   4
> +#define DP_MSA1                      0x20
> +#define DP_MSA2                      0x845c00
> +#define DP_OFFSET            0x1e0000
> +#define DP_HDCP                      0x2
> +#define DP_INT_RST           0xffff
> +#define DP_DPTX_RST          0x3ff
> +#define DP_CLK_EN            0x7
> +#define DP_SYNC_EN_MASK              0x3
> +#define DP_LINK_RATE_CAL     27
> +
> +#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..83cf0cc06ae2
> --- /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 DP_AUX_CMD_ADDR                      0x50
> +#define DP_AUX_WR_DATA0                      0x54
> +#define DP_AUX_WR_DATA1                      0x58
> +#define DP_AUX_WR_DATA2                      0x5c
> +#define DP_AUX_WR_DATA3                      0x60
> +#define DP_AUX_RD_DATA0                      0x64
> +#define DP_AUX_REQ                   0x74
> +#define DP_AUX_STATUS                        0x78
> +#define DP_DPTX_RST_CTRL             0x700
> +
> +#define DP_CFG_AUX_SYNC_LEN_SEL                      BIT(1)
> +#define DP_CFG_AUX_TIMER_TIMEOUT             BIT(2)
> +#define DP_CFG_AUX_MIN_PULSE_NUM             GENMASK(13, 9)
> +#define DP_CFG_AUX_REQ                               BIT(0)
> +#define DP_CFG_AUX_RST_N                     BIT(4)
> +#define DP_CFG_AUX_TIMEOUT                   BIT(0)
> +#define DP_CFG_AUX_READY_DATA_BYTE           GENMASK(16, 12)
> +#define DP_CFG_AUX                           GENMASK(24, 17)
> +#define DP_CFG_AUX_STATUS                    GENMASK(11, 4)
> +
> +#endif
> -- 
> 2.33.0
> 

-- 
With best wishes
Dmitry

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