drm/amdgpu: add new helper for handling EEPROM i2c transfers

Encapsulates the i2c protocol handling so other parts of the
driver can just tell it the offset and size of data to write.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov@amd.com>

drivers/gpu/drm/amd/amdgpu/Makefile

@@ -57,7 +57,8 @@ amdgpu-y += amdgpu_device.o amdgpu_kms.o \
 	amdgpu_xgmi.o amdgpu_csa.o amdgpu_ras.o amdgpu_vm_cpu.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_hdp.o
+	amdgpu_fw_attestation.o amdgpu_securedisplay.o amdgpu_hdp.o \
+	amdgpu_eeprom.o
 
 amdgpu-$(CONFIG_PROC_FS) += amdgpu_fdinfo.o
 

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

+/*
+ * Copyright 2021 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 "amdgpu_eeprom.h"
+#include "amdgpu.h"
+
+#define EEPROM_OFFSET_LENGTH 2
+
+int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
+		       u16 slave_addr, u16 eeprom_addr,
+		       u8 *eeprom_buf, u16 bytes, bool read)
+{
+	u8 eeprom_offset_buf[2];
+	u16 bytes_transferred;
+	struct i2c_msg msgs[] = {
+		{
+			.addr = slave_addr,
+			.flags = 0,
+			.len = EEPROM_OFFSET_LENGTH,
+			.buf = eeprom_offset_buf,
+		},
+		{
+			.addr = slave_addr,
+			.flags = read ? I2C_M_RD: 0,
+			.len = bytes,
+			.buf = eeprom_buf,
+		}
+	};
+	int r;
+
+	msgs[0].buf[0] = ((eeprom_addr >> 8) & 0xff);
+	msgs[0].buf[1] = (eeprom_addr & 0xff);
+
+	while (msgs[1].len) {
+		r = i2c_transfer(i2c_adap, msgs, ARRAY_SIZE(msgs));
+		if (r <= 0)
+			return r;
+		bytes_transferred = r - EEPROM_OFFSET_LENGTH;
+		eeprom_addr += bytes_transferred;
+		msgs[0].buf[0] = ((eeprom_addr >> 8) & 0xff);
+		msgs[0].buf[1] = (eeprom_addr & 0xff);
+		msgs[1].buf += bytes_transferred;
+		msgs[1].len -= bytes_transferred;
+	}
+
+	return 0;
+}

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

+/*
+ * Copyright 2021 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 _AMDGPU_EEPROM_H
+#define _AMDGPU_EEPROM_H
+
+#include <linux/i2c.h>
+
+int amdgpu_eeprom_xfer(struct i2c_adapter *i2c_adap,
+		       u16 slave_addr, u16 eeprom_addr,
+		       u8 *eeprom_buf, u16 bytes, bool read);
+
+
+#endif