[RFC PATCH 3/4] drivers: k3_fuse: Add fuse sub-system func calls

[Harsha Vardhan V M <h-vm@ti.com>]

Add K3_FUSE config option to add and enable fuse sub-system
implementation function calls.

Signed-off-by: Harsha Vardhan V M <h-vm@ti.com>
---
 drivers/misc/Kconfig   |  7 ++++
 drivers/misc/Makefile  |  1 +
 drivers/misc/k3_fuse.c | 78 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)
 create mode 100644 drivers/misc/k3_fuse.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index da84b35e804..834e0285097 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -468,6 +468,13 @@ config STM32MP_FUSE
 	  for STM32MP architecture.
 	  This API is needed for CMD_FUSE.
 
+config K3_FUSE
+	bool "Enable TI K3 fuse wrapper providing the fuse API"
+	depends on MISC && CMD_FUSE && CMD_FUSE_WRITEBUFF
+	help
+	  If you say Y here, you will get support for the fuse API (OTP)
+	  for TI K3 architecture.
+
 config STM32_RCC
 	bool "Enable RCC driver for the STM32 SoC's family"
 	depends on (ARCH_STM32 || ARCH_STM32MP) && MISC
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index dac805e4cdd..0b81ba2604f 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -48,6 +48,7 @@ obj-$(CONFIG_$(XPL_)I2C_EEPROM) += i2c_eeprom.o
 obj-$(CONFIG_IHS_FPGA) += ihs_fpga.o
 obj-$(CONFIG_IMX8) += imx8/
 obj-$(CONFIG_IMX_ELE) += imx_ele/
+obj-$(CONFIG_K3_FUSE) += k3_fuse.o
 obj-$(CONFIG_LED_STATUS) += status_led.o
 obj-$(CONFIG_LED_STATUS_GPIO) += gpio_led.o
 obj-$(CONFIG_MPC83XX_SERDES) += mpc83xx_serdes.o
diff --git a/drivers/misc/k3_fuse.c b/drivers/misc/k3_fuse.c
new file mode 100644
index 00000000000..4a8ff1f2523
--- /dev/null
+++ b/drivers/misc/k3_fuse.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2025 Texas Instruments Incorporated, <www.ti.com>
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <fuse.h>
+#include <linux/arm-smccc.h>
+#include <string.h>
+
+#define K3_SIP_OTP_WRITEBUFF 0xC2000000
+#define K3_SIP_OTP_WRITE 0xC2000001
+#define K3_SIP_OTP_READ 0xC2000002
+
+int fuse_read(u32 bank, u32 word, u32 *val)
+{
+	struct arm_smccc_res res;
+
+	if (bank != 0U) {
+		printf("Invalid bank argument, ONLY bank 0 is supported\n");
+		return -EINVAL;
+	}
+
+	/* Make SiP SMC call and send the word in the parameter register */
+	arm_smccc_smc(K3_SIP_OTP_READ, word,
+		      0, 0, 0, 0, 0, 0, &res);
+
+	*val = res.a1;
+	if (res.a0 != 0)
+		printf("SMC call failed: Error code %lu\n", res.a0);
+
+	return res.a0;
+}
+
+int fuse_sense(u32 bank, u32 word, u32 *val)
+{
+	return -EPERM;
+}
+
+int fuse_prog(u32 bank, u32 word, u32 val)
+{
+	struct arm_smccc_res res;
+	u32 mask = val;
+
+	if (bank != 0U) {
+		printf("Invalid bank argument, ONLY bank 0 is supported\n");
+		return -EINVAL;
+	}
+
+	/* Make SiP SMC call and send the word, val and mask in the parameter register */
+	arm_smccc_smc(K3_SIP_OTP_WRITE, word,
+		      val, mask, 0, 0, 0, 0, &res);
+
+	if (res.a0 != 0)
+		printf("SMC call failed: Error code %lu\n", res.a0);
+
+	return res.a0;
+}
+
+int fuse_override(u32 bank, u32 word, u32 val)
+{
+	return -EPERM;
+}
+
+int fuse_writebuff(ulong addr)
+{
+	struct arm_smccc_res res;
+
+	/* Make SiP SMC call and send the addr in the parameter register */
+	arm_smccc_smc(K3_SIP_OTP_WRITEBUFF, (unsigned long)addr,
+		      0, 0, 0, 0, 0, 0, &res);
+
+	if (res.a0 != 0)
+		printf("SMC call failed: Error code %lu\n", res.a0);
+
+	return res.a0;
+}
-- 
2.34.1