From: baihan li <libaihan@huawei.com>

Add dp aux read/write functions. They are basic functions
and will be used later.

Signed-off-by: Baihan Li <libaihan@huawei.com>
Signed-off-by: Yongbang Shi <shiyongbang@huawei.com>
---
ChangeLog:
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@intel.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 |  39 +++++
 drivers/gpu/drm/hisilicon/hibmc/dp/dp_reg.h  |  27 +++
 4 files changed, 232 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..eff4c39fa7e5
--- /dev/null
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h
@@ -0,0 +1,39 @@
+/* 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() */
+};
+
+static inline void hibmc_dp_reg_write_field(struct hibmc_dp_dev *dp, u32 offset, u32 mask, u32 val)
+{
+	u32 value;
+
+	mutex_lock(&dp->lock);
+
+	value = readl(dp->base + offset);
+	value &= ~mask;
+	value |= FIELD_PREP(mask, val);
+	writel(value, dp->base + offset);
+
+	mutex_unlock(&dp->lock);
+}
+
+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

Hi Yongbang,

kernel test robot noticed the following build warnings:

[auto build test WARNING on linus/master]
[also build test WARNING on drm-misc/drm-misc-next v6.12-rc7 next-20241112]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Yongbang-Shi/drm-hisilicon-hibmc-add-dp-aux-in-hibmc/20241113-013224
base:   linus/master
patch link:    https://lore.kernel.org/r/20241112132348.2631150-2-shiyongbang%40huawei.com
patch subject: [PATCH v4 drm-dp 1/5] drm/hisilicon/hibmc: add dp aux in hibmc
config: x86_64-buildonly-randconfig-003-20241113 (https://download.01.org/0day-ci/archive/20241113/202411131438.RZWYrWTE-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241113/202411131438.RZWYrWTE-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202411131438.RZWYrWTE-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c:9:
   In file included from drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h:14:
   In file included from include/drm/display/drm_dp_helper.h:27:
   In file included from include/linux/i2c.h:19:
   In file included from include/linux/regulator/consumer.h:35:
   In file included from include/linux/suspend.h:5:
   In file included from include/linux/swap.h:9:
   In file included from include/linux/memcontrol.h:21:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   In file included from drivers/gpu/drm/hisilicon/hibmc/dp/dp_aux.c:9:
>> drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h:31:11: warning: result of comparison of constant 18446744073709551615 with expression of type 'typeof (_Generic((mask), char: (unsigned char)0, unsigned char: (unsigned char)0, signed char: (unsigned char)0, unsigned short: (unsigned short)0, short: (unsigned short)0, unsigned int: (unsigned int)0, int: (unsigned int)0, unsigned long: (unsigned long)0, long: (unsigned long)0, unsigned long long: (unsigned long long)0, long long: (unsigned long long)0, default: (mask)))' (aka 'unsigned int') is always false [-Wtautological-constant-out-of-range-compare]
      31 |         value |= FIELD_PREP(mask, val);
         |                  ^~~~~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:115:3: note: expanded from macro 'FIELD_PREP'
     115 |                 __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: ");    \
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/bitfield.h:72:53: note: expanded from macro '__BF_FIELD_CHECK'
      72 |                 BUILD_BUG_ON_MSG(__bf_cast_unsigned(_mask, _mask) >     \
         |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~
      73 |                                  __bf_cast_unsigned(_reg, ~0ull),       \
         |                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      74 |                                  _pfx "type of reg too small for mask"); \
         |                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/build_bug.h:39:58: note: expanded from macro 'BUILD_BUG_ON_MSG'
      39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
         |                                     ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
   include/linux/compiler_types.h:517:22: note: expanded from macro 'compiletime_assert'
     517 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
         |         ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler_types.h:505:23: note: expanded from macro '_compiletime_assert'
     505 |         __compiletime_assert(condition, msg, prefix, suffix)
         |         ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/compiler_types.h:497:9: note: expanded from macro '__compiletime_assert'
     497 |                 if (!(condition))                                       \
         |                       ^~~~~~~~~
   2 warnings generated.


vim +31 drivers/gpu/drm/hisilicon/hibmc/dp/dp_comm.h

    22	
    23	static inline void hibmc_dp_reg_write_field(struct hibmc_dp_dev *dp, u32 offset, u32 mask, u32 val)
    24	{
    25		u32 value;
    26	
    27		mutex_lock(&dp->lock);
    28	
    29		value = readl(dp->base + offset);
    30		value &= ~mask;
  > 31		value |= FIELD_PREP(mask, val);
    32		writel(value, dp->base + offset);
    33	
    34		mutex_unlock(&dp->lock);
    35	}
    36	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki