soc: qcom: Add driver to print xbl log on console from fs

Add driver to capture xbl log from reserved memory region
and print on console when user requests.

Use cat /sys/module/xbl_log/xbl_log to see xbl log.

Change-Id: I5d34a4be63244f354ce70cfac8df2724b6a0537b
Signed-off-by: Vinay Sudra <vsudra@codeaurora.org>

drivers/soc/qcom/Kconfig

@@ -1282,5 +1282,14 @@ config QCOM_AOP_SET_DDR
 	  into an exposed sysfs node to send to AOP. The driver expects the Cap
 	  frequency of DDR based on SKU.
 
+config DUMP_XBL_LOG
+	bool "print xbl log on console from fs"
+	help
+	  This driver is used to capture xbl log from reserved memory  region
+	  defined separately in each device tree and print on console when user
+	  requests. User can perform below command to print xbl log stored in
+	  reserved memory region:
+		cat /sys/module/xbl_log/xbl_log
+
 source "drivers/soc/qcom/icnss2/Kconfig"
 endmenu

drivers/soc/qcom/Makefile

@@ -116,3 +116,4 @@ obj-$(CONFIG_MSM_SLATECOM) += slatecom_spi.o
 obj-$(CONFIG_MSM_SLATECOM_INTERFACE) += slatecom_interface.o
 obj-$(CONFIG_QCOM_AOP_SET_DDR) += aop-set-ddr.o
 obj-$(CONFIG_CPU_V7) += idle-v7.o
+obj-$(CONFIG_DUMP_XBL_LOG) += dump_boot_log.o

drivers/soc/qcom/dump_boot_log.c

@@ -0,0 +1,138 @@
+// 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/ioport.h>
+#include <linux/memblock.h>
+#include <linux/of_address.h>
+#include <linux/kthread.h>
+#include <linux/slab.h>
+
+static char *xbl_log_buf;
+size_t xbl_log_size;
+
+static ssize_t xbl_log_show(struct file *fp,
+		struct kobject *kobj, struct bin_attribute *bin_attr,
+		char *buf, loff_t offset, size_t count)
+{
+	if (offset < xbl_log_size)
+		return scnprintf(buf, count, "%s", xbl_log_buf + offset);
+
+	return 0;
+}
+
+static struct bin_attribute attribute =
+__BIN_ATTR(xbl_log, 0444, xbl_log_show, NULL, 0);
+
+static void free_xbl_log_buf(phys_addr_t paddr, size_t size)
+{
+	unsigned long pfn_start = 0, pfn_end = 0, pfn_idx = 0;
+
+	memblock_free(paddr, size);
+	pfn_start = paddr >> PAGE_SHIFT;
+	pfn_end = (paddr + size) >> PAGE_SHIFT;
+	for (pfn_idx = pfn_start; pfn_idx < pfn_end; pfn_idx++)
+		free_reserved_page(pfn_to_page(pfn_idx));
+}
+
+static int xbl_log_kthread(void *arg)
+{
+	int err = 1;
+	struct module_kobject *mkobj;
+	struct device_node *parent = NULL, *node = NULL;
+	struct resource res_log = {0,};
+	phys_addr_t xbl_log_paddr = 0;
+	void *addr = NULL;
+
+	mkobj = kcalloc(1, sizeof(*mkobj), GFP_KERNEL);
+	if (!mkobj)
+		return 1;
+
+	mkobj->mod = THIS_MODULE;
+	mkobj->kobj.kset = module_kset;
+
+	err = kobject_init_and_add(&mkobj->kobj, &module_ktype, NULL, "xbl_log");
+	if (err) {
+		pr_err("xbl_log: cannot create kobject\n");
+		goto kobj_fail;
+	}
+
+	kobject_get(&mkobj->kobj);
+	if (IS_ERR_OR_NULL(&mkobj->kobj)) {
+		err = PTR_ERR(&mkobj->kobj);
+		goto kobj_fail;
+	}
+
+	err = sysfs_create_bin_file(&mkobj->kobj, &attribute);
+	if (err) {
+		pr_err("xbl_log: sysfs entry creation failed\n");
+		goto kobj_fail;
+	}
+
+	parent = of_find_node_by_path("/reserved-memory");
+	if (!parent) {
+		pr_err("xbl_log: reserved-memory node missing\n");
+		goto kobj_fail;
+	}
+
+	node = of_find_node_by_name(parent, "uefi_log");
+	if (!node) {
+		pr_err("xbl_log: uefi_log node missing\n");
+		goto node_fail;
+	}
+
+	if (of_address_to_resource(node, 0, &res_log))
+		goto node_fail;
+
+	xbl_log_paddr = res_log.start;
+	xbl_log_size = resource_size(&res_log) - 1;
+	pr_debug("xbl_log_addr = %x, size=%d\n", xbl_log_paddr, xbl_log_size);
+
+	addr = memremap(xbl_log_paddr, xbl_log_size, MEMREMAP_WB);
+	if (!addr) {
+		pr_err("xbl_log: memremap failed\n");
+		goto remap_fail;
+	}
+
+	xbl_log_buf = kzalloc(xbl_log_size, GFP_KERNEL);
+	if (xbl_log_buf) {
+		memcpy(xbl_log_buf, addr, xbl_log_size);
+		xbl_log_buf[xbl_log_size-1] = '\0';
+		memunmap(addr);
+		if (xbl_log_size)
+			free_xbl_log_buf(xbl_log_paddr, xbl_log_size);
+		return 0;
+	}
+
+	kfree(xbl_log_buf);
+remap_fail:
+	if (node)
+		of_node_put(node);
+node_fail:
+	if (parent)
+		of_node_put(parent);
+kobj_fail:
+	kobject_del(&mkobj->kobj);
+	kfree(mkobj);
+	return 1;
+}
+
+static int __init dump_boot_log_init(void)
+{
+	struct task_struct *xbl_log_task =
+		kthread_run(xbl_log_kthread, NULL, "xbl_log");
+
+	if (PTR_ERR_OR_ZERO(xbl_log_task))
+		return PTR_ERR(xbl_log_task);
+	else
+		return 0;
+}
+
+subsys_initcall(dump_boot_log_init);
+MODULE_DESCRIPTION("dump xbl log");
+MODULE_LICENSE("GPL v2");