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SubjectRe: [RFC PATCH 1/1] soc: qcom: Add driver to read secondary bootloader (XBL) log
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On 22/08/2023 13:15, Ninad Naik wrote:
> Qualcomm secondary bootloader (XBL) boot log holds information to
> identify various firmware configuration currently set on the SoC.
> The XBL log is stored in a predefined reserved memory region.
>
> This drivers provides a way to print XBL logs on the console. To
> do so, it provides a debugfs entry which captures the logs stored
> in this reserved memory region. This entry can now be used to read
> and print the XBL logs to console.
>
> User can use the below command to print XBL log to console:
> cat /sys/kernel/debug/xbl_log
>
> Signed-off-by: Ninad Naik <quic_ninanaik@quicinc.com>
> ---
> drivers/soc/qcom/Kconfig | 13 +++
> drivers/soc/qcom/Makefile | 1 +
> drivers/soc/qcom/dump_xbl_log.c | 139 ++++++++++++++++++++++++++++++++
> 3 files changed, 153 insertions(+)
> create mode 100644 drivers/soc/qcom/dump_xbl_log.c
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index 715348869d04..4489d37e924d 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -291,4 +291,17 @@ config QCOM_INLINE_CRYPTO_ENGINE
> tristate
> select QCOM_SCM
>
> +config QCOM_DUMP_XBL_LOG
> + tristate "Qualcomm driver to print XBL logs on console from debugfs"
> + help
> + This driver is used to capture secondary bootloader (xbl) log
> + from a reserved memory region and provide a debugfs entry to read
> + logs captured from this memory region and print them on console.
> + User can use below command to print the xbl log on console:
> +
> + cat /sys/kernel/debug/xbl_log
> +
> + These logs help to identify firmware configuration information on
> + the SoC. The name of the built module will be dump_xbl_log
> +
> endmenu
> diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
> index bbca2e1e55bb..aac088a1a0b6 100644
> --- a/drivers/soc/qcom/Makefile
> +++ b/drivers/soc/qcom/Makefile
> @@ -32,3 +32,4 @@ obj-$(CONFIG_QCOM_KRYO_L2_ACCESSORS) += kryo-l2-accessors.o
> obj-$(CONFIG_QCOM_ICC_BWMON) += icc-bwmon.o
> qcom_ice-objs += ice.o
> obj-$(CONFIG_QCOM_INLINE_CRYPTO_ENGINE) += qcom_ice.o
> +obj-$(CONFIG_QCOM_DUMP_XBL_LOG) += dump_xbl_log.o
> diff --git a/drivers/soc/qcom/dump_xbl_log.c b/drivers/soc/qcom/dump_xbl_log.c
> new file mode 100644
> index 000000000000..ea335a5e660b
> --- /dev/null
> +++ b/drivers/soc/qcom/dump_xbl_log.c
> @@ -0,0 +1,139 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2021, The Linux Foundation. All rights reserved.
> + */
> +
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/memblock.h>
> +#include <linux/of_address.h>
> +#include <linux/err.h>
> +#include <linux/debugfs.h>
> +
> +struct xbl_log_data {
> + struct device *dev;
> + size_t buf_size;
> + void __iomem *xbl_buf;
> + struct dentry *dbg_file;
> + struct debugfs_blob_wrapper dbg_data;
> +};
> +
> +static int map_addr_range(struct device_node **parent, const char *name,
> + struct xbl_log_data *xbl_data)
> +{
> + struct device_node *node;
> + struct resource res;
> + int ret;
> +
> + node = of_find_node_by_name(*parent, name);
> + if (!node)
> + return -ENODEV;
> +
> + ret = of_address_to_resource(node, 0, &res);
> + if (ret) {
> + dev_err(xbl_data->dev, "Failed to parse memory region\n");
> + return ret;
> + }
> + of_node_put(node);
> +
> + if (!resource_size(&res)) {
> + dev_err(xbl_data->dev, "Failed to parse memory region size\n");
> + return -ENODEV;
> + }
> +
> + xbl_data->buf_size = resource_size(&res) - 1;
> + xbl_data->xbl_buf = devm_memremap(xbl_data->dev, res.start,
> + xbl_data->buf_size, MEMREMAP_WB);
> + if (!xbl_data->xbl_buf) {
> + dev_err(xbl_data->dev, "%s: memory remap failed\n", name);
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +
> +static int xbl_log_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct xbl_log_data *xbl_data;
> + struct device_node *parent;
> + int ret;
> +
> + xbl_data = devm_kzalloc(dev, sizeof(*xbl_data), GFP_KERNEL);
> + if (!xbl_data)
> + return -ENOMEM;
> +
> + xbl_data->dev = &pdev->dev;
> + platform_set_drvdata(pdev, xbl_data);
> +
> + parent = of_find_node_by_path("/reserved-memory");
> + if (!parent) {
> + dev_err(xbl_data->dev, "reserved-memory node missing\n");
> + return -ENODEV;
> + }
> +
> + ret = map_addr_range(&parent, "uefi-log", xbl_data);

This driver really needs a proper device tree bindings, rather than
parsing the device tree manually here in the driver.

Pl look at ./Documentation/devicetree/bindings/reserved-memory/qcom*

This should also help you getting rid of all these parsing code.

--srini



> + if (ret)
> + goto put_node;
> +
> + xbl_data->dbg_data.data = xbl_data->xbl_buf;
> + xbl_data->dbg_data.size = xbl_data->buf_size;
> + xbl_data->dbg_file = debugfs_create_blob("xbl_log", 0400, NULL,
> + &xbl_data->dbg_data);
> + if (IS_ERR(xbl_data->dbg_file)) {
> + dev_err(xbl_data->dev, "failed to create debugfs entry\n");
> + ret = PTR_ERR(xbl_data->dbg_file);
> + }
> +
> +put_node:
> + of_node_put(parent);
> + return ret;
> +}
> +
> +static int xbl_log_remove(struct platform_device *pdev)
> +{
> + struct xbl_log_data *xbl_data = platform_get_drvdata(pdev);
> +
> + debugfs_remove_recursive(xbl_data->dbg_file);
> + return 0;
> +}
> +
> +static struct platform_driver xbl_log_driver = {
> + .probe = xbl_log_probe,
> + .remove = xbl_log_remove,
> + .driver = {
> + .name = "xbl-log",
> + },
> +};
> +
> +static struct platform_device xbl_log_device = {
> + .name = "xbl-log",
> +};
> +
> +static int __init xbl_log_init(void)
> +{
> + int ret = 0;
> +
> + ret = platform_driver_register(&xbl_log_driver);
> + if (!ret) {
> + ret = platform_device_register(&xbl_log_device);
> + if (ret)
> + platform_driver_unregister(&xbl_log_driver);
> + }
> + return ret;
> +}
> +
> +static void __exit xbl_log_exit(void)
> +{
> + platform_device_unregister(&xbl_log_device);
> + platform_driver_unregister(&xbl_log_driver);
> +}
> +
> +module_init(xbl_log_init);
> +module_exit(xbl_log_exit);
> +
> +MODULE_DESCRIPTION("Qualcomm Technologies, Inc. (QTI) XBL log driver");
> +MODULE_LICENSE("GPL");

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