nvmem: sec-qfprom: Add Qualcomm secure QFPROM support

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>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230823132744.350618-18-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 96 insertions, 0 deletions

diff --git a/drivers/nvmem/sec-qfprom.c b/drivers/nvmem/sec-qfprom.c
new file mode 100644
index 000000000000..e48c2dc0c44b
--- /dev/null
+++ b/drivers/nvmem/sec-qfprom.c
@@ -0,0 +1,96 @@
+// 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;
+
+	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");