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From:   Zhenneng Li <lizhenneng@kylinos.cn>
To:     Alex Deucher <alexander.deucher@amd.com>
Cc:     =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        Pan Xinhui <Xinhui.Pan@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Hawking Zhang <Hawking.Zhang@amd.com>,
        Tao Zhou <tao.zhou1@amd.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        Jack Xiao <Jack.Xiao@amd.com>, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Zhenneng Li <lizhenneng@kylinos.cn>
Subject: [PATCH] drm/amdgpu: use native mode for dp aux transfer
Date:   Wed, 20 Jul 2022 10:16:39 +0800
Message-Id: <20220720021639.58406-1-lizhenneng@kylinos.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When using amdgpu for e8860, the monitor sometimes haven't any signal,
and the kernel reports some errors:
[   17.317302][ 2] [ T1045] [drm:amdgpu_atombios_dp_link_train [amdgpu]] *ERROR* channel eq failed: 5 tries
[   17.326963][ 2] [ T1045] [drm:amdgpu_atombios_dp_link_train [amdgpu]] *ERROR* channel eq failed
But if I use radeon for e8860, everything are always normal, the reason is
that radeon use native mode and amdgpu use atombios mode
when init dp aux, so when I use native mode for amdgpu, everything
are always normal.

Signed-off-by: Zhenneng Li <lizhenneng@kylinos.cn>
Change-Id: Ia9a2be3ab03e56b1c8337fdbf713461196fbc58f
---
 drivers/gpu/drm/amd/amdgpu/Makefile          |   2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu.h          |   2 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c |   5 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c | 273 +++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c      |   4 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h     |   2 +
 drivers/gpu/drm/amd/amdgpu/atombios_dp.c     |   5 +-
 7 files changed, 290 insertions(+), 3 deletions(-)
 create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c

diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
index 3e0e2eb7e235..2913cf46f848 100644
--- a/drivers/gpu/drm/amd/amdgpu/Makefile
+++ b/drivers/gpu/drm/amd/amdgpu/Makefile
@@ -58,7 +58,7 @@ amdgpu-y += amdgpu_device.o amdgpu_kms.o \
 	amdgpu_vm_sdma.o amdgpu_discovery.o amdgpu_ras_eeprom.o amdgpu_nbio.o \
 	amdgpu_umc.o smu_v11_0_i2c.o amdgpu_fru_eeprom.o amdgpu_rap.o \
 	amdgpu_fw_attestation.o amdgpu_securedisplay.o \
-	amdgpu_eeprom.o amdgpu_mca.o amdgpu_psp_ta.o amdgpu_lsdma.o
+	amdgpu_eeprom.o amdgpu_mca.o amdgpu_psp_ta.o amdgpu_lsdma.o amdgpu_dp_auxch.o
 
 amdgpu-$(CONFIG_PROC_FS) += amdgpu_fdinfo.o
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 30ce6bb6fa77..15e0288b1997 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -238,6 +238,8 @@ extern int amdgpu_num_kcq;
 #define AMDGPU_VCNFW_LOG_SIZE (32 * 1024)
 extern int amdgpu_vcnfw_log;
 
+extern int amdgpu_auxch;
+
 #define AMDGPU_VM_MAX_NUM_CTX			4096
 #define AMDGPU_SG_THRESHOLD			(256*1024*1024)
 #define AMDGPU_DEFAULT_GTT_SIZE_MB		3072ULL /* 3GB by default */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
index 9ba4817a9148..68c8d79e2937 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
@@ -49,7 +49,10 @@ static struct amdgpu_i2c_bus_rec amdgpu_atombios_get_bus_rec_for_i2c_gpio(ATOM_G
 
 	memset(&i2c, 0, sizeof(struct amdgpu_i2c_bus_rec));
 
-	i2c.mask_clk_reg = le16_to_cpu(gpio->usClkMaskRegisterIndex);
+	if (amdgpu_auxch)
+		i2c.mask_clk_reg = le16_to_cpu(gpio->usClkMaskRegisterIndex) * 4;
+	else
+		i2c.mask_clk_reg = le16_to_cpu(gpio->usClkMaskRegisterIndex);
 	i2c.mask_data_reg = le16_to_cpu(gpio->usDataMaskRegisterIndex);
 	i2c.en_clk_reg = le16_to_cpu(gpio->usClkEnRegisterIndex);
 	i2c.en_data_reg = le16_to_cpu(gpio->usDataEnRegisterIndex);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c
new file mode 100644
index 000000000000..22078f1ca936
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dp_auxch.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright 2015 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: Dave Airlie
+ */
+
+#include "amdgpu.h"
+
+#define 	AUX_SW_RX_OVERFLOW			(1 << 8)
+#define 	AUX_SW_RX_HPD_DISCON			(1 << 9)
+#define 	AUX_SW_RX_PARTIAL_BYTE			(1 << 10)
+#define 	AUX_SW_NON_AUX_MODE			(1 << 11)
+#define 	AUX_SW_RX_SYNC_INVALID_L		(1 << 17)
+#define 	AUX_SW_RX_SYNC_INVALID_H		(1 << 18)
+#define 	AUX_SW_RX_INVALID_START			(1 << 19)
+#define 	AUX_SW_RX_RECV_NO_DET			(1 << 20)
+#define 	AUX_SW_RX_RECV_INVALID_H		(1 << 22)
+#define 	AUX_SW_RX_RECV_INVALID_V		(1 << 23)
+#define		AUX_CONTROL				0x6200
+#define 	AUX_HPD_SEL(x)				(((x) & 0x7) << 20)
+#define 	AUX_EN					(1 << 0)
+#define 	AUX_LS_READ_EN				(1 << 8)
+#define		AUX_SW_CONTROL				0x6204
+#define 	AUX_SW_WR_BYTES(x)			(((x) & 0x1f) << 16)
+#define AUX_SW_DATA					0x6218
+#define AUX_SW_DATA_RW					(1 << 0)
+#define AUX_SW_AUTOINCREMENT_DISABLE			(1 << 31)
+#define AUX_SW_INTERRUPT_CONTROL			0x620c
+#define 	AUX_SW_DONE_ACK				(1 << 1)
+#define 	AUX_SW_GO				(1 << 0)
+#define AUX_SW_STATUS					0x6210
+#define 	AUX_SW_DONE				(1 << 0)
+#define 	AUX_SW_RX_TIMEOUT			(1 << 7)
+#define AUX_SW_DATA_RW					(1 << 0)
+#define AUX_SW_DATA_MASK(x)				(((x) & 0xff) << 8)
+
+#define AUX_RX_ERROR_FLAGS (AUX_SW_RX_OVERFLOW |	     \
+			    AUX_SW_RX_HPD_DISCON |	     \
+			    AUX_SW_RX_PARTIAL_BYTE |	     \
+			    AUX_SW_NON_AUX_MODE |	     \
+			    AUX_SW_RX_SYNC_INVALID_L |	     \
+			    AUX_SW_RX_SYNC_INVALID_H |	     \
+			    AUX_SW_RX_INVALID_START |	     \
+			    AUX_SW_RX_RECV_NO_DET |	     \
+			    AUX_SW_RX_RECV_INVALID_H |	     \
+			    AUX_SW_RX_RECV_INVALID_V)
+
+#define AUX_SW_REPLY_GET_BYTE_COUNT(x) (((x) >> 24) & 0x1f)
+
+#define BARE_ADDRESS_SIZE 3
+
+#define R100_MM_INDEX                   0x0000
+#define R100_MM_DATA                      0x0004
+#define AMDGPU_MIN_MMIO_SIZE 0x10000
+uint32_t venus_mm_rreg_slow(struct amdgpu_device *adev, uint32_t reg)
+{
+        unsigned long flags;
+        uint32_t ret;
+
+        spin_lock_irqsave(&adev->mmio_idx_lock, flags);
+        writel(reg, ((void __iomem *)adev->rmmio) + R100_MM_INDEX);
+        ret = readl(((void __iomem *)adev->rmmio) + R100_MM_DATA);
+        spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
+        return ret;
+}
+void venus_mm_wreg_slow(struct amdgpu_device *adev, uint32_t reg, uint32_t v)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&adev->mmio_idx_lock, flags);
+        writel(reg, ((void __iomem *)adev->rmmio) + R100_MM_INDEX);
+        writel(v, ((void __iomem *)adev->rmmio) + R100_MM_DATA);
+        spin_unlock_irqrestore(&adev->mmio_idx_lock, flags);
+}
+static inline uint32_t venus_mm_rreg(struct amdgpu_device *adev, uint32_t reg,
+                                    bool always_indirect)
+{
+        /* The mmio size is 64kb at minimum. Allows the if to be optimized out. */
+        if ((reg < adev->rmmio_size || reg < AMDGPU_MIN_MMIO_SIZE) && !always_indirect)
+                return readl(((void __iomem *)adev->rmmio) + reg);
+        else
+                return venus_mm_rreg_slow(adev, reg);
+}
+static inline void venus_mm_wreg(struct amdgpu_device *adev, uint32_t reg, uint32_t v,
+                                bool always_indirect)
+{
+        if ((reg < adev->rmmio_size || reg < AMDGPU_MIN_MMIO_SIZE) && !always_indirect)
+                writel(v, ((void __iomem *)adev->rmmio) + reg);
+        else
+                venus_mm_wreg_slow(adev, reg, v);
+}
+
+#define RREG32_VENUS(reg) venus_mm_rreg(adev, (reg), false)
+#define WREG32_VENUS(reg, v) venus_mm_wreg(adev, (reg), (v), false)
+
+static const u32 aux_offset[] =
+{
+	0x6200 - 0x6200,
+	0x6250 - 0x6200,
+	0x62a0 - 0x6200,
+	0x6300 - 0x6200,
+	0x6350 - 0x6200,
+	0x63a0 - 0x6200,
+};
+
+ssize_t
+amdgpu_dp_aux_transfer_native(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
+{
+	struct amdgpu_i2c_chan *chan =
+		container_of(aux, struct amdgpu_i2c_chan, aux);
+	struct drm_device *dev = chan->dev;
+	struct amdgpu_device *adev = dev->dev_private;
+	int ret = 0, i;
+	uint32_t tmp, ack = 0;
+	int instance = chan->rec.i2c_id & 0xf;
+	u8 byte;
+	u8 *buf = msg->buffer;
+	int retry_count = 0;
+	int bytes;
+	int msize;
+	bool is_write = false;
+
+	if (WARN_ON(msg->size > 16))
+		return -E2BIG;
+
+	switch (msg->request & ~DP_AUX_I2C_MOT) {
+	case DP_AUX_NATIVE_WRITE:
+	case DP_AUX_I2C_WRITE:
+		is_write = true;
+		break;
+	case DP_AUX_NATIVE_READ:
+	case DP_AUX_I2C_READ:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/* work out two sizes required */
+	msize = 0;
+	bytes = BARE_ADDRESS_SIZE;
+	if (msg->size) {
+		msize = msg->size - 1;
+		bytes++;
+		if (is_write)
+			bytes += msg->size;
+	}
+
+	mutex_lock(&chan->mutex);
+
+	/* switch the pad to aux mode */
+	tmp = RREG32_VENUS(chan->rec.mask_clk_reg);
+	tmp |= (1 << 16);
+	WREG32_VENUS(chan->rec.mask_clk_reg, tmp);
+
+	/* setup AUX control register with correct HPD pin */
+	tmp = RREG32_VENUS(AUX_CONTROL + aux_offset[instance]);
+	tmp &= AUX_HPD_SEL(0x7);
+	tmp |= AUX_HPD_SEL(chan->rec.hpd);
+	tmp |= AUX_EN | AUX_LS_READ_EN;
+
+	WREG32_VENUS(AUX_CONTROL + aux_offset[instance], tmp);
+
+	/* atombios appears to write this twice lets copy it */
+	WREG32_VENUS(AUX_SW_CONTROL + aux_offset[instance],
+	       AUX_SW_WR_BYTES(bytes));
+	WREG32_VENUS(AUX_SW_CONTROL + aux_offset[instance],
+	       AUX_SW_WR_BYTES(bytes));
+
+	/* write the data header into the registers */
+	/* request, address, msg size */
+	byte = (msg->request << 4) | ((msg->address >> 16) & 0xf);
+	WREG32_VENUS(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte) | AUX_SW_AUTOINCREMENT_DISABLE);
+
+	byte = (msg->address >> 8) & 0xff;
+	WREG32_VENUS(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte));
+
+	byte = msg->address & 0xff;
+	WREG32_VENUS(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte));
+
+	byte = msize;
+	WREG32_VENUS(AUX_SW_DATA + aux_offset[instance],
+	       AUX_SW_DATA_MASK(byte));
+
+	/* if we are writing - write the msg buffer */
+	if (is_write) {
+		for (i = 0; i < msg->size; i++) {
+			WREG32_VENUS(AUX_SW_DATA + aux_offset[instance],
+			       AUX_SW_DATA_MASK(buf[i]));
+		}
+	}
+
+	/* clear the ACK */
+	WREG32_VENUS(AUX_SW_INTERRUPT_CONTROL + aux_offset[instance], AUX_SW_DONE_ACK);
+
+	/* write the size and GO bits */
+	WREG32_VENUS(AUX_SW_CONTROL + aux_offset[instance],
+	       AUX_SW_WR_BYTES(bytes) | AUX_SW_GO);
+
+	/* poll the status registers - TODO irq support */
+	do {
+		tmp = RREG32_VENUS(AUX_SW_STATUS + aux_offset[instance]);
+		if (tmp & AUX_SW_DONE) {
+			break;
+		}
+		usleep_range(100, 200);
+	} while (retry_count++ < 1000);
+
+	if (retry_count >= 1000) {
+		DRM_ERROR("auxch hw never signalled completion, error %08x\n", tmp);
+		ret = -EIO;
+		goto done;
+	}
+
+	if (tmp & AUX_SW_RX_TIMEOUT) {
+		ret = -ETIMEDOUT;
+		goto done;
+	}
+	if (tmp & AUX_RX_ERROR_FLAGS) {
+		DRM_DEBUG_KMS_RATELIMITED("dp_aux_ch flags not zero: %08x\n",
+					  tmp);
+		ret = -EIO;
+		goto done;
+	}
+
+	bytes = AUX_SW_REPLY_GET_BYTE_COUNT(tmp);
+	if (bytes) {
+		WREG32_VENUS(AUX_SW_DATA + aux_offset[instance],
+		       AUX_SW_DATA_RW | AUX_SW_AUTOINCREMENT_DISABLE);
+
+		tmp = RREG32_VENUS(AUX_SW_DATA + aux_offset[instance]);
+		ack = (tmp >> 8) & 0xff;
+
+		for (i = 0; i < bytes - 1; i++) {
+			tmp = RREG32_VENUS(AUX_SW_DATA + aux_offset[instance]);
+			if (buf)
+				buf[i] = (tmp >> 8) & 0xff;
+		}
+		if (buf)
+			ret = bytes - 1;
+	}
+
+	WREG32_VENUS(AUX_SW_INTERRUPT_CONTROL + aux_offset[instance], AUX_SW_DONE_ACK);
+
+	if (is_write)
+		ret = msg->size;
+done:
+	mutex_unlock(&chan->mutex);
+
+	if (ret >= 0)
+		msg->reply = ack >> 4;
+	return ret;
+}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 8890300766a5..2ac7636ddafb 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -180,6 +180,7 @@ int amdgpu_num_kcq = -1;
 int amdgpu_smartshift_bias;
 int amdgpu_use_xgmi_p2p = 1;
 int amdgpu_vcnfw_log;
+int amdgpu_auxch = 0;
 
 static void amdgpu_drv_delayed_reset_work_handler(struct work_struct *work);
 
@@ -882,6 +883,9 @@ MODULE_PARM_DESC(smu_pptable_id,
 	"specify pptable id to be used (-1 = auto(default) value, 0 = use pptable from vbios, > 0 = soft pptable id)");
 module_param_named(smu_pptable_id, amdgpu_smu_pptable_id, int, 0444);
 
+MODULE_PARM_DESC(auxch, "Use native auxch experimental support (1 = enable, 0 = disable, -1 = auto)");
+module_param_named(auxch, amdgpu_auxch, int, 0444);
+
 /* These devices are not supported by amdgpu.
  * They are supported by the mach64, r128, radeon drivers
  */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
index f80b4838cea1..95fffc110c75 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
@@ -619,5 +619,7 @@ int amdgpu_display_crtc_page_flip_target(struct drm_crtc *crtc,
 				uint32_t page_flip_flags, uint32_t target,
 				struct drm_modeset_acquire_ctx *ctx);
 extern const struct drm_mode_config_funcs amdgpu_mode_funcs;
+extern ssize_t
+amdgpu_dp_aux_transfer_native(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg);
 
 #endif
diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
index 87c41e0e9b7c..846ecc315665 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
@@ -188,7 +188,10 @@ amdgpu_atombios_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *m
 void amdgpu_atombios_dp_aux_init(struct amdgpu_connector *amdgpu_connector)
 {
 	amdgpu_connector->ddc_bus->rec.hpd = amdgpu_connector->hpd.hpd;
-	amdgpu_connector->ddc_bus->aux.transfer = amdgpu_atombios_dp_aux_transfer;
+	if (amdgpu_auxch)
+		amdgpu_connector->ddc_bus->aux.transfer = amdgpu_dp_aux_transfer_native;
+	else
+		amdgpu_connector->ddc_bus->aux.transfer = amdgpu_atombios_dp_aux_transfer;
 	amdgpu_connector->ddc_bus->aux.drm_dev = amdgpu_connector->base.dev;
 
 	drm_dp_aux_init(&amdgpu_connector->ddc_bus->aux);
-- 
2.25.1