Re: [PATCH v5 2/2] nvmem: sec-qfprom: Add Qualcomm secure QFPROM support
From: Mukesh Ojha
Date: Thu Jul 27 2023 - 09:26:51 EST
On 7/27/2023 12:09 PM, Mukesh Ojha wrote:
Hi,
Some questions, may not need to be addressed if the reason is
known
On 7/24/2023 2:08 PM, Komal Bajaj wrote:
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,
Linux will have to use secure calls to read the region.
With that motivation, add secure qfprom driver.
Signed-off-by: Komal Bajaj <quic_kbajaj@xxxxxxxxxxx>
---
drivers/nvmem/Kconfig | 13 +++++
drivers/nvmem/Makefile | 2 +
drivers/nvmem/sec-qfprom.c | 101 +++++++++++++++++++++++++++++++++++++
3 files changed, 116 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-$(CONFIG_NVMEM_QCOM_SEC_QFPROM) += nvmem_sec_qfprom.o
+nvmem_sec_qfprom-y := sec-qfprom.o
Are we just doing this for just renaming the object ?
obj-$(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..bc68053b7d94
--- /dev/null
+++ b/drivers/nvmem/sec-qfprom.c
@@ -0,0 +1,101 @@
+// 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];
+ }
Getting secure read from fuse region is fine here, since we have to read
4 byte from trustzone, but this restriction of reading is also there
for sm8{4|5}50 soc's where byte by byte reading is protected and
granularity set to 4 byte (qfprom_reg_read() in drivers/nvmem/qfprom.c)
is will result in abort, in that case this function need to export this
logic.
+
+ 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;
+
+ ret = devm_pm_runtime_enable(dev);
+ if (ret)
+ return ret;
+
+ 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,
Why don't we have remove/remove_new callbacks?
Same comment apply for drivers/nvmem/qfprom.c
Ignore this comment; Something new learnt with devm_* api
implementation.
-Mukesh
+ .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");
--
2.40.1
-Mukesh