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From:   Komal Bajaj <quic_kbajaj@quicinc.com>
To:     <agross@kernel.org>, <andersson@kernel.org>,
        <konrad.dybcio@linaro.org>, <srinivas.kandagatla@linaro.org>,
        <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <conor+dt@kernel.org>
CC:     <linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>,
        Komal Bajaj <quic_kbajaj@quicinc.com>
Subject: [PATCH v6 2/2] nvmem: sec-qfprom: Add Qualcomm secure QFPROM support
Date:   Tue, 1 Aug 2023 12:10:25 +0530
Message-ID: <20230801064025.17381-3-quic_kbajaj@quicinc.com>
In-Reply-To: <20230801064025.17381-1-quic_kbajaj@quicinc.com>
References: <20230801064025.17381-1-quic_kbajaj@quicinc.com>
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For some of the Qualcomm SoC's, it is possible that
some of the fuse regions or entire qfprom region is
protected from non-secure access. In such situations,
the OS will have to use secure calls to read the region.
With that motivation, add secure qfprom driver.

Signed-off-by: Komal Bajaj <quic_kbajaj@quicinc.com>
---
 drivers/nvmem/Kconfig      | 13 +++++
 drivers/nvmem/Makefile     |  2 +
 drivers/nvmem/sec-qfprom.c | 97 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+)
 create mode 100644 drivers/nvmem/sec-qfprom.c

diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index b291b27048c7..764fc5feb26c 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -216,6 +216,19 @@ config NVMEM_QCOM_QFPROM
 	  This driver can also be built as a module. If so, the module
 	  will be called nvmem_qfprom.

+config NVMEM_QCOM_SEC_QFPROM
+        tristate "QCOM SECURE QFPROM Support"
+        depends on ARCH_QCOM || COMPILE_TEST
+        depends on HAS_IOMEM
+        depends on OF
+        select QCOM_SCM
+        help
+          Say y here to enable secure QFPROM support. The secure QFPROM provides access
+          functions for QFPROM data to rest of the drivers via nvmem interface.
+
+          This driver can also be built as a module. If so, the module will be called
+          nvmem_sec_qfprom.
+
 config NVMEM_RAVE_SP_EEPROM
 	tristate "Rave SP EEPROM Support"
 	depends on RAVE_SP_CORE
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index f82431ec8aef..e248d3daadf3 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -44,6 +44,8 @@ obj-$(CONFIG_NVMEM_NINTENDO_OTP)	+= nvmem-nintendo-otp.o
 nvmem-nintendo-otp-y			:= nintendo-otp.o
 obj-$(CONFIG_NVMEM_QCOM_QFPROM)		+= nvmem_qfprom.o
 nvmem_qfprom-y				:= qfprom.o
+obj-$(CONFIG_NVMEM_QCOM_SEC_QFPROM)	+= nvmem_sec_qfprom.o
+nvmem_sec_qfprom-y			:= sec-qfprom.o
 obj-$(CONFIG_NVMEM_RAVE_SP_EEPROM)	+= nvmem-rave-sp-eeprom.o
 nvmem-rave-sp-eeprom-y			:= rave-sp-eeprom.o
 obj-$(CONFIG_NVMEM_RMEM) 		+= nvmem-rmem.o
diff --git a/drivers/nvmem/sec-qfprom.c b/drivers/nvmem/sec-qfprom.c
new file mode 100644
index 000000000000..868a91c81197
--- /dev/null
+++ b/drivers/nvmem/sec-qfprom.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/firmware/qcom/qcom_scm.h>
+#include <linux/mod_devicetable.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+/**
+ * struct sec_qfprom - structure holding secure qfprom attributes
+ *
+ * @base: starting physical address for secure qfprom corrected address space.
+ * @dev: qfprom device structure.
+ */
+struct sec_qfprom {
+	phys_addr_t base;
+	struct device *dev;
+};
+
+static int sec_qfprom_reg_read(void *context, unsigned int reg, void *_val, size_t bytes)
+{
+	struct sec_qfprom *priv = context;
+	unsigned int i;
+	u8 *val = _val;
+	u32 read_val;
+	u8 *tmp;
+
+	for (i = 0; i < bytes; i++, reg++) {
+		if (i == 0 || reg % 4 == 0) {
+			if (qcom_scm_io_readl(priv->base + (reg & ~3), &read_val)) {
+				dev_err(priv->dev, "Couldn't access fuse register\n");
+				return -EINVAL;
+			}
+			tmp = (u8 *)&read_val;
+		}
+
+		val[i] = tmp[reg & 3];
+	}
+
+	return 0;
+}
+
+static int sec_qfprom_probe(struct platform_device *pdev)
+{
+	struct nvmem_config econfig = {
+		.name = "sec-qfprom",
+		.stride = 1,
+		.word_size = 1,
+		.id = NVMEM_DEVID_AUTO,
+		.reg_read = sec_qfprom_reg_read,
+	};
+	struct device *dev = &pdev->dev;
+	struct nvmem_device *nvmem;
+	struct sec_qfprom *priv;
+	struct resource *res;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+
+	priv->base = res->start;
+
+	econfig.size = resource_size(res);
+	econfig.dev = dev;
+	econfig.priv = priv;
+
+	priv->dev = dev;
+
+	nvmem = devm_nvmem_register(dev, &econfig);
+
+	return PTR_ERR_OR_ZERO(nvmem);
+}
+
+static const struct of_device_id sec_qfprom_of_match[] = {
+	{ .compatible = "qcom,sec-qfprom" },
+	{/* sentinel */},
+};
+MODULE_DEVICE_TABLE(of, sec_qfprom_of_match);
+
+static struct platform_driver qfprom_driver = {
+	.probe = sec_qfprom_probe,
+	.driver = {
+		.name = "qcom_sec_qfprom",
+		.of_match_table = sec_qfprom_of_match,
+	},
+};
+module_platform_driver(qfprom_driver);
+MODULE_DESCRIPTION("Qualcomm Secure QFPROM driver");
+MODULE_LICENSE("GPL");
--
2.41.0