[PATCH 05/40] drm/amdgpu: add new helper for handling EEPROM i2c transfers

[Luben Tuikov]

From: Alex Deucher <alexander.deucher at amd.com>

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 at amd.com>
Reviewed-by: Luben Tuikov <luben.tuikov at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/Makefile        |  3 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c | 67 ++++++++++++++++++++++
 drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.h | 34 +++++++++++
 3 files changed, 103 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
 create mode 100644 drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.h

diff --git a/drivers/gpu/drm/amd/amdgpu/Makefile b/drivers/gpu/drm/amd/amdgpu/Makefile
index c56320e78c0e1f..7d292485ca7cf2 100644
--- a/drivers/gpu/drm/amd/amdgpu/Makefile
+++ b/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
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
new file mode 100644
index 00000000000000..10551660343278
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.c
@@ -0,0 +1,67 @@
+/*
+ * 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;
+}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.h
new file mode 100644
index 00000000000000..9301e5678910ad
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.h
@@ -0,0 +1,34 @@
+/*
+ * 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
-- 
2.32.0