drm/amdgpu: Vega20 SMU I2C HW engine controller.

Implement HW I2C enigne controller to be used by the RAS EEPROM
table manager. This is based on code from ATITOOLs.

v2:
Rename the file and all function prefixes to smu_v11_0_i2c

By Luben's observation always fill the TX fifo to full so
we don't have garbadge interpreted by the slave as valid data.

v3:
Remove preemption disable as the HW I2C controller will not
stop the clock on empty TX fifo and so it's not critical to
keep not empty queue.
Switch to fast mode 400 khz SCL clock for faster read and write.

v5:
Restore clock gating before releasing I2C bus and fix some
style comments.

v6:
squash in warning fix, fix includes (Alex)
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Luben Tuikov <Luben.Tuikov@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/Makefile

@@ -54,7 +54,7 @@ amdgpu-y += amdgpu_device.o amdgpu_kms.o \
 	amdgpu_gtt_mgr.o amdgpu_vram_mgr.o amdgpu_virt.o amdgpu_atomfirmware.o \
 	amdgpu_vf_error.o amdgpu_sched.o amdgpu_debugfs.o amdgpu_ids.o \
 	amdgpu_gmc.o amdgpu_xgmi.o amdgpu_csa.o amdgpu_ras.o amdgpu_vm_cpu.o \
-	amdgpu_vm_sdma.o amdgpu_pmu.o amdgpu_discovery.o amdgpu_ras_eeprom.o
+	amdgpu_vm_sdma.o amdgpu_pmu.o amdgpu_discovery.o amdgpu_ras_eeprom.o smu_v11_0_i2c.o
 
 amdgpu-$(CONFIG_PERF_EVENTS) += amdgpu_pmu.o
 

drivers/gpu/drm/amd/amdgpu/amdgpu_ras_eeprom.c

@@ -25,6 +25,7 @@
 #include "amdgpu.h"
 #include "amdgpu_ras.h"
 #include <linux/bits.h>
+#include "smu_v11_0_i2c.h"
 
 #define EEPROM_I2C_TARGET_ADDR 0xA0
 
@@ -118,7 +119,7 @@ int amdgpu_ras_eeprom_init(struct amdgpu_ras_eeprom_control *control)
 
 	switch (adev->asic_type) {
 	case CHIP_VEGA20:
-	/*TODO Add MI-60 */
+		ret = smu_v11_0_i2c_eeprom_control_init(&control->eeprom_accessor);
 		break;
 
 	default:
@@ -170,7 +171,7 @@ void amdgpu_ras_eeprom_fini(struct amdgpu_ras_eeprom_control *control)
 
 	switch (adev->asic_type) {
 	case CHIP_VEGA20:
-		/*TODO Add MI-60 */
+		smu_v11_0_i2c_eeprom_control_fini(&control->eeprom_accessor);
 		break;
 
 	default:

drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c

+/*
+ * Copyright 2019 Advanced Micro Devices, 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.
+ *
+ */
+
+#include "smuio/smuio_11_0_0_offset.h"
+#include "smuio/smuio_11_0_0_sh_mask.h"
+
+#include "smu_v11_0_i2c.h"
+#include "amdgpu.h"
+#include "soc15_common.h"
+#include <drm/drm_fixed.h>
+#include <drm/drm_drv.h>
+#include "amdgpu_amdkfd.h"
+#include <linux/i2c.h>
+#include <linux/pci.h>
+#include "amdgpu_ras.h"
+
+/* error codes */
+#define I2C_OK                0
+#define I2C_NAK_7B_ADDR_NOACK 1
+#define I2C_NAK_TXDATA_NOACK  2
+#define I2C_TIMEOUT           4
+#define I2C_SW_TIMEOUT        8
+#define I2C_ABORT             0x10
+
+/* I2C transaction flags */
+#define I2C_NO_STOP	1
+#define I2C_RESTART	2
+
+#define to_amdgpu_device(x) (container_of(x, struct amdgpu_ras, eeprom_control.eeprom_accessor))->adev
+#define to_eeprom_control(x) container_of(x, struct amdgpu_ras_eeprom_control, eeprom_accessor)
+
+static void smu_v11_0_i2c_set_clock_gating(struct i2c_adapter *control, bool en)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t reg = RREG32_SOC15(SMUIO, 0, mmSMUIO_PWRMGT);
+
+	reg = REG_SET_FIELD(reg, SMUIO_PWRMGT, i2c_clk_gate_en, en ? 1 : 0);
+	WREG32_SOC15(SMUIO, 0, mmSMUIO_PWRMGT, reg);
+}
+
+
+static void smu_v11_0_i2c_enable(struct i2c_adapter *control, bool enable)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_ENABLE, enable ? 1 : 0);
+}
+
+static void smu_v11_0_i2c_clear_status(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	/* do */
+	{
+		RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_CLR_INTR);
+
+	} /* while (reg_CKSVII2C_ic_clr_intr == 0) */
+}
+
+static void smu_v11_0_i2c_configure(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t reg = 0;
+
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_CON, IC_SLAVE_DISABLE, 1);
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_CON, IC_RESTART_EN, 1);
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_CON, IC_10BITADDR_MASTER, 0);
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_CON, IC_10BITADDR_SLAVE, 0);
+	/* Standard mode */
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_CON, IC_MAX_SPEED_MODE, 2);
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_CON, IC_MASTER_MODE, 1);
+
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_CON, reg);
+}
+
+static void smu_v11_0_i2c_set_clock(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+
+	/*
+	 * Standard mode speed, These values are taken from SMUIO MAS,
+	 * but are different from what is given is
+	 * Synopsys spec. The values here are based on assumption
+	 * that refclock is 100MHz
+	 *
+	 * Configuration for standard mode; Speed = 100kbps
+	 * Scale linearly, for now only support standard speed clock
+	 * This will work only with 100M ref clock
+	 *
+	 * TBD:Change the calculation to take into account ref clock values also.
+	 */
+
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_FS_SPKLEN, 2);
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_SS_SCL_HCNT, 120);
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_SS_SCL_LCNT, 130);
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_SDA_HOLD, 20);
+}
+
+static void smu_v11_0_i2c_set_address(struct i2c_adapter *control, uint8_t address)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+
+	/* Convert fromr 8-bit to 7-bit address */
+	address >>= 1;
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_TAR, (address & 0xFF));
+}
+
+static uint32_t smu_v11_0_i2c_poll_tx_status(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t ret = I2C_OK;
+	uint32_t reg, reg_c_tx_abrt_source;
+
+	/*Check if transmission is completed */
+	unsigned long  timeout_counter = jiffies + msecs_to_jiffies(20);
+
+	do {
+		if (time_after(jiffies, timeout_counter)) {
+			ret |= I2C_SW_TIMEOUT;
+			break;
+		}
+
+		reg = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_STATUS);
+
+	} while (REG_GET_FIELD(reg, CKSVII2C_IC_STATUS, TFE) == 0);
+
+	if (ret != I2C_OK)
+		return ret;
+
+	/* This only checks if NAK is received and transaction got aborted */
+	reg = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_INTR_STAT);
+
+	if (REG_GET_FIELD(reg, CKSVII2C_IC_INTR_STAT, R_TX_ABRT) == 1) {
+		reg_c_tx_abrt_source = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_TX_ABRT_SOURCE);
+		DRM_INFO("TX was terminated, IC_TX_ABRT_SOURCE val is:%x", reg_c_tx_abrt_source);
+
+		/* Check for stop due to NACK */
+		if (REG_GET_FIELD(reg_c_tx_abrt_source,
+				  CKSVII2C_IC_TX_ABRT_SOURCE,
+				  ABRT_TXDATA_NOACK) == 1) {
+
+			ret |= I2C_NAK_TXDATA_NOACK;
+
+		} else if (REG_GET_FIELD(reg_c_tx_abrt_source,
+					 CKSVII2C_IC_TX_ABRT_SOURCE,
+					 ABRT_7B_ADDR_NOACK) == 1) {
+
+			ret |= I2C_NAK_7B_ADDR_NOACK;
+		} else {
+			ret |= I2C_ABORT;
+		}
+
+		smu_v11_0_i2c_clear_status(control);
+	}
+
+	return ret;
+}
+
+static uint32_t smu_v11_0_i2c_poll_rx_status(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t ret = I2C_OK;
+	uint32_t reg_ic_status, reg_c_tx_abrt_source;
+
+	reg_c_tx_abrt_source = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_TX_ABRT_SOURCE);
+
+	/* If slave is not present */
+	if (REG_GET_FIELD(reg_c_tx_abrt_source,
+			  CKSVII2C_IC_TX_ABRT_SOURCE,
+			  ABRT_7B_ADDR_NOACK) == 1) {
+		ret |= I2C_NAK_7B_ADDR_NOACK;
+
+		smu_v11_0_i2c_clear_status(control);
+	} else {  /* wait till some data is there in RXFIFO */
+		/* Poll for some byte in RXFIFO */
+		unsigned long  timeout_counter = jiffies + msecs_to_jiffies(20);
+
+		do {
+			if (time_after(jiffies, timeout_counter)) {
+				ret |= I2C_SW_TIMEOUT;
+				break;
+			}
+
+			reg_ic_status = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_STATUS);
+
+		} while (REG_GET_FIELD(reg_ic_status, CKSVII2C_IC_STATUS, RFNE) == 0);
+	}
+
+	return ret;
+}
+
+
+
+
+/**
+ * smu_v11_0_i2c_transmit - Send a block of data over the I2C bus to a slave device.
+ *
+ * @address: The I2C address of the slave device.
+ * @data: The data to transmit over the bus.
+ * @numbytes: The amount of data to transmit.
+ * @i2c_flag: Flags for transmission
+ *
+ * Returns 0 on success or error.
+ */
+static uint32_t smu_v11_0_i2c_transmit(struct i2c_adapter *control,
+				  uint8_t address, uint8_t *data,
+				  uint32_t numbytes, uint32_t i2c_flag)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t bytes_sent, reg, ret = 0;
+	unsigned long  timeout_counter;
+
+	bytes_sent = 0;
+
+	DRM_DEBUG_DRIVER("I2C_Transmit(), address = %x, bytes = %d , data: ",
+		 (uint16_t)address, numbytes);
+
+	if (drm_debug & DRM_UT_DRIVER) {
+		print_hex_dump(KERN_INFO, "data: ", DUMP_PREFIX_NONE,
+			       16, 1, data, numbytes, false);
+	}
+
+	/* Set the I2C slave address */
+	smu_v11_0_i2c_set_address(control, address);
+	/* Enable I2C */
+	smu_v11_0_i2c_enable(control, true);
+
+	/* Clear status bits */
+	smu_v11_0_i2c_clear_status(control);
+
+
+	timeout_counter = jiffies + msecs_to_jiffies(20);
+
+	while (numbytes > 0) {
+		reg = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_STATUS);
+		if (REG_GET_FIELD(reg, CKSVII2C_IC_STATUS, TFNF)) {
+			do {
+				reg = 0;
+				/*
+				 * Prepare transaction, no need to set RESTART. I2C engine will send
+				 * START as soon as it sees data in TXFIFO
+				 */
+				if (bytes_sent == 0)
+					reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, RESTART,
+							    (i2c_flag & I2C_RESTART) ? 1 : 0);
+				reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, DAT, data[bytes_sent]);
+
+				/* determine if we need to send STOP bit or not */
+				if (numbytes == 1)
+					/* Final transaction, so send stop unless I2C_NO_STOP */
+					reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, STOP,
+							    (i2c_flag & I2C_NO_STOP) ? 0 : 1);
+				/* Write */
+				reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, CMD, 0);
+				WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_DATA_CMD, reg);
+
+				/* Record that the bytes were transmitted */
+				bytes_sent++;
+				numbytes--;
+
+				reg = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_STATUS);
+
+			} while (numbytes &&  REG_GET_FIELD(reg, CKSVII2C_IC_STATUS, TFNF));
+		}
+
+		/*
+		 * We waited too long for the transmission FIFO to become not-full.
+		 * Exit the loop with error.
+		 */
+		if (time_after(jiffies, timeout_counter)) {
+			ret |= I2C_SW_TIMEOUT;
+			goto Err;
+		}
+	}
+
+	ret = smu_v11_0_i2c_poll_tx_status(control);
+
+Err:
+	/* Any error, no point in proceeding */
+	if (ret != I2C_OK) {
+		if (ret & I2C_SW_TIMEOUT)
+			DRM_ERROR("TIMEOUT ERROR !!!");
+
+		if (ret & I2C_NAK_7B_ADDR_NOACK)
+			DRM_ERROR("Received I2C_NAK_7B_ADDR_NOACK !!!");
+
+
+		if (ret & I2C_NAK_TXDATA_NOACK)
+			DRM_ERROR("Received I2C_NAK_TXDATA_NOACK !!!");
+	}
+
+	return ret;
+}
+
+
+/**
+ * smu_v11_0_i2c_receive - Receive a block of data over the I2C bus from a slave device.
+ *
+ * @address: The I2C address of the slave device.
+ * @numbytes: The amount of data to transmit.
+ * @i2c_flag: Flags for transmission
+ *
+ * Returns 0 on success or error.
+ */
+static uint32_t smu_v11_0_i2c_receive(struct i2c_adapter *control,
+				 uint8_t address, uint8_t *data,
+				 uint32_t numbytes, uint8_t i2c_flag)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t bytes_received, ret = I2C_OK;
+
+	bytes_received = 0;
+
+	/* Set the I2C slave address */
+	smu_v11_0_i2c_set_address(control, address);
+
+	/* Enable I2C */
+	smu_v11_0_i2c_enable(control, true);
+
+	while (numbytes > 0) {
+		uint32_t reg = 0;
+
+		smu_v11_0_i2c_clear_status(control);
+
+
+		/* Prepare transaction */
+
+		/* Each time we disable I2C, so this is not a restart */
+		if (bytes_received == 0)
+			reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, RESTART,
+					    (i2c_flag & I2C_RESTART) ? 1 : 0);
+
+		reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, DAT, 0);
+		/* Read */
+		reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, CMD, 1);
+
+		/* Transmitting last byte */
+		if (numbytes == 1)
+			/* Final transaction, so send stop if requested */
+			reg = REG_SET_FIELD(reg, CKSVII2C_IC_DATA_CMD, STOP,
+					    (i2c_flag & I2C_NO_STOP) ? 0 : 1);
+
+		WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_DATA_CMD, reg);
+
+		ret = smu_v11_0_i2c_poll_rx_status(control);
+
+		/* Any error, no point in proceeding */
+		if (ret != I2C_OK) {
+			if (ret & I2C_SW_TIMEOUT)
+				DRM_ERROR("TIMEOUT ERROR !!!");
+
+			if (ret & I2C_NAK_7B_ADDR_NOACK)
+				DRM_ERROR("Received I2C_NAK_7B_ADDR_NOACK !!!");
+
+			if (ret & I2C_NAK_TXDATA_NOACK)
+				DRM_ERROR("Received I2C_NAK_TXDATA_NOACK !!!");
+
+			break;
+		}
+
+		reg = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_DATA_CMD);
+		data[bytes_received] = REG_GET_FIELD(reg, CKSVII2C_IC_DATA_CMD, DAT);
+
+		/* Record that the bytes were received */
+		bytes_received++;
+		numbytes--;
+	}
+
+	DRM_DEBUG_DRIVER("I2C_Receive(), address = %x, bytes = %d, data :",
+		  (uint16_t)address, bytes_received);
+
+	if (drm_debug & DRM_UT_DRIVER) {
+		print_hex_dump(KERN_INFO, "data: ", DUMP_PREFIX_NONE,
+			       16, 1, data, bytes_received, false);
+	}
+
+	return ret;
+}
+
+static void smu_v11_0_i2c_abort(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t reg = 0;
+
+	/* Enable I2C engine; */
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_ENABLE, ENABLE, 1);
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_ENABLE, reg);
+
+	/* Abort previous transaction */
+	reg = REG_SET_FIELD(reg, CKSVII2C_IC_ENABLE, ABORT, 1);
+	WREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_ENABLE, reg);
+
+	DRM_DEBUG_DRIVER("I2C_Abort() Done.");
+}
+
+
+static bool smu_v11_0_i2c_activity_done(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+
+	const uint32_t IDLE_TIMEOUT = 1024;
+	uint32_t timeout_count = 0;
+	uint32_t reg_ic_enable, reg_ic_enable_status, reg_ic_clr_activity;
+
+	reg_ic_enable_status = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_ENABLE_STATUS);
+	reg_ic_enable = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_ENABLE);
+
+
+	if ((REG_GET_FIELD(reg_ic_enable, CKSVII2C_IC_ENABLE, ENABLE) == 0) &&
+	    (REG_GET_FIELD(reg_ic_enable_status, CKSVII2C_IC_ENABLE_STATUS, IC_EN) == 1)) {
+		/*
+		 * Nobody is using I2C engine, but engine remains active because
+		 * someone missed to send STOP
+		 */
+		smu_v11_0_i2c_abort(control);
+	} else if (REG_GET_FIELD(reg_ic_enable, CKSVII2C_IC_ENABLE, ENABLE) == 0) {
+		/* Nobody is using I2C engine */
+		return true;
+	}
+
+	/* Keep reading activity bit until it's cleared */
+	do {
+		reg_ic_clr_activity = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_CLR_ACTIVITY);
+
+		if (REG_GET_FIELD(reg_ic_clr_activity,
+		    CKSVII2C_IC_CLR_ACTIVITY, CLR_ACTIVITY) == 0)
+			return true;
+
+		++timeout_count;
+
+	} while (timeout_count < IDLE_TIMEOUT);
+
+	return false;
+}
+
+static void smu_v11_0_i2c_init(struct i2c_adapter *control)
+{
+	/* Disable clock gating */
+	smu_v11_0_i2c_set_clock_gating(control, false);
+
+	if (!smu_v11_0_i2c_activity_done(control))
+		DRM_WARN("I2C busy !");
+
+	/* Disable I2C */
+	smu_v11_0_i2c_enable(control, false);
+
+	/* Configure I2C to operate as master and in standard mode */
+	smu_v11_0_i2c_configure(control);
+
+	/* Initialize the clock to 50 kHz default */
+	smu_v11_0_i2c_set_clock(control);
+
+}
+
+static void smu_v11_0_i2c_fini(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	uint32_t reg_ic_enable_status, reg_ic_enable;
+
+	smu_v11_0_i2c_enable(control, false);
+
+	/* Double check if disabled, else force abort */
+	reg_ic_enable_status = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_ENABLE_STATUS);
+	reg_ic_enable = RREG32_SOC15(SMUIO, 0, mmCKSVII2C_IC_ENABLE);
+
+	if ((REG_GET_FIELD(reg_ic_enable, CKSVII2C_IC_ENABLE, ENABLE) == 0) &&
+	    (REG_GET_FIELD(reg_ic_enable_status,
+			   CKSVII2C_IC_ENABLE_STATUS, IC_EN) == 1)) {
+		/*
+		 * Nobody is using I2C engine, but engine remains active because
+		 * someone missed to send STOP
+		 */
+		smu_v11_0_i2c_abort(control);
+	}
+
+	/* Restore clock gating */
+	smu_v11_0_i2c_set_clock_gating(control, true);
+
+}
+
+static bool smu_v11_0_i2c_bus_lock(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+
+	/* Send  PPSMC_MSG_RequestI2CBus */
+	if (!adev->powerplay.pp_funcs->smu_i2c_bus_access)
+		goto Fail;
+
+
+	if (!adev->powerplay.pp_funcs->smu_i2c_bus_access(adev->powerplay.pp_handle, true))
+		return true;
+
+Fail:
+	return false;
+}
+
+static bool smu_v11_0_i2c_bus_unlock(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+
+	/* Send  PPSMC_MSG_RequestI2CBus */
+	if (!adev->powerplay.pp_funcs->smu_i2c_bus_access)
+		goto Fail;
+
+	/* Send  PPSMC_MSG_ReleaseI2CBus */
+	if (!adev->powerplay.pp_funcs->smu_i2c_bus_access(adev->powerplay.pp_handle,
+							     false))
+		return true;
+
+Fail:
+	return false;
+}
+
+/***************************** EEPROM I2C GLUE ****************************/
+
+static uint32_t smu_v11_0_i2c_eeprom_read_data(struct i2c_adapter *control,
+					       uint8_t address,
+					       uint8_t *data,
+					       uint32_t numbytes)
+{
+	uint32_t  ret = 0;
+
+	/* First 2 bytes are dummy write to set EEPROM address */
+	ret = smu_v11_0_i2c_transmit(control, address, data, 2, I2C_NO_STOP);
+	if (ret != I2C_OK)
+		goto Fail;
+
+	/* Now read data starting with that address */
+	ret = smu_v11_0_i2c_receive(control, address, data + 2, numbytes - 2,
+				    I2C_RESTART);
+
+Fail:
+	if (ret != I2C_OK)
+		DRM_ERROR("ReadData() - I2C error occurred :%x", ret);
+
+	return ret;
+}
+
+static uint32_t smu_v11_0_i2c_eeprom_write_data(struct i2c_adapter *control,
+						uint8_t address,
+						uint8_t *data,
+						uint32_t numbytes)
+{
+	uint32_t  ret;
+
+	ret = smu_v11_0_i2c_transmit(control, address, data, numbytes, 0);
+
+	if (ret != I2C_OK)
+		DRM_ERROR("WriteI2CData() - I2C error occurred :%x", ret);
+	else
+		/*
+		 * According to EEPROM spec there is a MAX of 10 ms required for
+		 * EEPROM to flush internal RX buffer after STOP was issued at the
+		 * end of write transaction. During this time the EEPROM will not be
+		 * responsive to any more commands - so wait a bit more.
+		 *
+		 * TODO Improve to wait for first ACK for slave address after
+		 * internal write cycle done.
+		 */
+		msleep(10);
+
+	return ret;
+
+}
+
+static void lock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+	struct amdgpu_ras_eeprom_control *control = to_eeprom_control(i2c);
+
+	if (!smu_v11_0_i2c_bus_lock(i2c)) {
+		DRM_ERROR("Failed to lock the bus from SMU");
+		return;
+	}
+
+	control->bus_locked = true;
+}
+
+static int trylock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+	WARN_ONCE(1, "This operation not supposed to run in atomic context!");
+	return false;
+}
+
+static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+	struct amdgpu_ras_eeprom_control *control = to_eeprom_control(i2c);
+
+	if (!smu_v11_0_i2c_bus_unlock(i2c)) {
+		DRM_ERROR("Failed to unlock the bus from SMU");
+		return;
+	}
+
+	control->bus_locked = false;
+}
+
+static const struct i2c_lock_operations smu_v11_0_i2c_i2c_lock_ops = {
+	.lock_bus = lock_bus,
+	.trylock_bus = trylock_bus,
+	.unlock_bus = unlock_bus,
+};
+
+static int smu_v11_0_i2c_eeprom_i2c_xfer(struct i2c_adapter *i2c_adap,
+			      struct i2c_msg *msgs, int num)
+{
+	int i, ret;
+	struct amdgpu_ras_eeprom_control *control = to_eeprom_control(i2c_adap);
+
+	if (!control->bus_locked) {
+		DRM_ERROR("I2C bus unlocked, stopping transaction!");
+		return -EIO;
+	}
+
+	smu_v11_0_i2c_init(i2c_adap);
+
+	for (i = 0; i < num; i++) {
+		if (msgs[i].flags & I2C_M_RD)
+			ret = smu_v11_0_i2c_eeprom_read_data(i2c_adap,
+							(uint8_t)msgs[i].addr,
+							msgs[i].buf, msgs[i].len);
+		else
+			ret = smu_v11_0_i2c_eeprom_write_data(i2c_adap,
+							 (uint8_t)msgs[i].addr,
+							 msgs[i].buf, msgs[i].len);
+
+		if (ret != I2C_OK) {
+			num = -EIO;
+			break;
+		}
+	}
+
+	smu_v11_0_i2c_fini(i2c_adap);
+	return num;
+}
+
+static u32 smu_v11_0_i2c_eeprom_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+
+static const struct i2c_algorithm smu_v11_0_i2c_eeprom_i2c_algo = {
+	.master_xfer = smu_v11_0_i2c_eeprom_i2c_xfer,
+	.functionality = smu_v11_0_i2c_eeprom_i2c_func,
+};
+
+int smu_v11_0_i2c_eeprom_control_init(struct i2c_adapter *control)
+{
+	struct amdgpu_device *adev = to_amdgpu_device(control);
+	int res;
+
+	control->owner = THIS_MODULE;
+	control->class = I2C_CLASS_SPD;
+	control->dev.parent = &adev->pdev->dev;
+	control->algo = &smu_v11_0_i2c_eeprom_i2c_algo;
+	snprintf(control->name, sizeof(control->name), "RAS EEPROM");
+	control->lock_ops = &smu_v11_0_i2c_i2c_lock_ops;
+
+	res = i2c_add_adapter(control);
+	if (res)
+		DRM_ERROR("Failed to register hw i2c, err: %d\n", res);
+
+	return res;
+}
+
+void smu_v11_0_i2c_eeprom_control_fini(struct i2c_adapter *control)
+{
+	i2c_del_adapter(control);
+}
+
+/*
+ * Keep this for future unit test if bugs arise
+ */
+#if 0
+#define I2C_TARGET_ADDR 0xA0
+
+bool smu_v11_0_i2c_test_bus(struct i2c_adapter *control)
+{
+
+	uint32_t ret = I2C_OK;
+	uint8_t data[6] = {0xf, 0, 0xde, 0xad, 0xbe, 0xef};
+
+
+	DRM_INFO("Begin");
+
+	if (!smu_v11_0_i2c_bus_lock(control)) {
+		DRM_ERROR("Failed to lock the bus!.");
+		return false;
+	}
+
+	smu_v11_0_i2c_init(control);
+
+	/* Write 0xde to address 0x0000 on the EEPROM */
+	ret = smu_v11_0_i2c_eeprom_write_data(control, I2C_TARGET_ADDR, data, 6);
+
+	ret = smu_v11_0_i2c_eeprom_read_data(control, I2C_TARGET_ADDR, data, 6);
+
+	smu_v11_0_i2c_fini(control);
+
+	smu_v11_0_i2c_bus_unlock(control);
+
+
+	DRM_INFO("End");
+	return true;
+}
+#endif

drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.h

+/*
+ * Copyright 2019 Advanced Micro Devices, 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.
+ *
+ */
+
+#ifndef SMU_V11_I2C_CONTROL_H
+#define SMU_V11_I2C_CONTROL_H
+
+#include <linux/types.h>
+
+struct i2c_adapter;
+
+int smu_v11_0_i2c_eeprom_control_init(struct i2c_adapter *control);
+void smu_v11_0_i2c_eeprom_control_fini(struct i2c_adapter *control);
+
+#endif