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From:   Mukesh Ojha <quic_mojha@quicinc.com>
To:     <corbet@lwn.net>, <agross@kernel.org>, <andersson@kernel.org>,
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CC:     <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
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        <linux-gpio@vger.kernel.org>,
        "Mukesh Ojha" <quic_mojha@quicinc.com>
Subject: [PATCH v4 10/21] soc: qcom: Add qcom's pstore minidump driver support
Date:   Wed, 28 Jun 2023 18:04:37 +0530
Message-ID: <1687955688-20809-11-git-send-email-quic_mojha@quicinc.com>
In-Reply-To: <1687955688-20809-1-git-send-email-quic_mojha@quicinc.com>
References: <1687955688-20809-1-git-send-email-quic_mojha@quicinc.com>
MIME-Version: 1.0
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This driver was inspired from the fact pstore ram region should be
fixed and boot firmware need to have awarness about this region,
so that it will be persistent across boot. But, there are many
QCOM SoC which does not support warm boot from hardware but they
have minidump support from the software, and for them, there is
no need of this pstore ram region to be fixed, but at the same
time have interest in the pstore frontends data. So, this driver
get the dynamic reserved region from the ram and register the
ramoops platform device.

 +---------+     +---------+   +--------+     +---------+
 | console |     | pmsg    |   | ftrace |     | dmesg   |
 +---------+     +---------+   +--------+     +---------+
       |             |             |              |
       |             |             |              |
       +------------------------------------------+
                          |
                         \ /
                  +----------------+
            (1)   |pstore frontends|
                  +----------------+
                          |
                         \ /
                 +------------------- +
            (2)  | pstore backend(ram)|
                 +--------------------+
                          |
                         \ /
                 +--------------------+
            (3)  |qcom_pstore_minidump|
                 +--------------------+
                          |
                         \ /
                   +---------------+
            (4)    | qcom_minidump |
                   +---------------+

This driver will route all the pstore front data to the stored
in qcom pstore reserved region and the reason of showing an
arrow from (3) to (4) as qcom_pstore_minidump driver will register
all the available frontends region with qcom minidump driver
in upcoming patch.

Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
---
 drivers/soc/qcom/Kconfig                | 12 +++++
 drivers/soc/qcom/Makefile               |  1 +
 drivers/soc/qcom/qcom_pstore_minidump.c | 85 +++++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 drivers/soc/qcom/qcom_pstore_minidump.c

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 1834213fd652..fbf08e30feda 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -306,4 +306,16 @@ config QCOM_MINIDUMP_SMEM
 
 	  This config should be enabled if the low level minidump is implemented
 	  as part of SMEM.
+
+config QCOM_PSTORE_MINIDUMP
+	tristate "Pstore support for QCOM Minidump"
+	depends on ARCH_QCOM
+	depends on PSTORE_RAM
+	depends on QCOM_MINIDUMP
+	help
+	  Enablement of this driver ensures that ramoops region can be anywhere
+	  reserved in ram instead of being fixed address which needs boot firmware
+	  awareness. So, this driver creates plaform device and registers available
+	  frontend region with the Qualcomm's minidump driver.
+
 endmenu
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 737d868757ac..1ab59c1b364d 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -36,3 +36,4 @@ qcom_ice-objs			+= ice.o
 obj-$(CONFIG_QCOM_INLINE_CRYPTO_ENGINE)	+= qcom_ice.o
 obj-$(CONFIG_QCOM_MINIDUMP) += qcom_minidump.o
 obj-$(CONFIG_QCOM_MINIDUMP_SMEM) += qcom_minidump_smem.o
+obj-$(CONFIG_QCOM_PSTORE_MINIDUMP) += qcom_pstore_minidump.o
diff --git a/drivers/soc/qcom/qcom_pstore_minidump.c b/drivers/soc/qcom/qcom_pstore_minidump.c
new file mode 100644
index 000000000000..b07cd10340df
--- /dev/null
+++ b/drivers/soc/qcom/qcom_pstore_minidump.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (c) 2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/platform_device.h>
+#include <linux/pstore_ram.h>
+
+struct qcom_ramoops_dd {
+	struct ramoops_platform_data qcom_ramoops_pdata;
+	struct platform_device *ramoops_pdev;
+};
+
+static int qcom_ramoops_probe(struct platform_device *pdev)
+{
+	struct device_node *of_node = pdev->dev.of_node;
+	struct qcom_ramoops_dd *qcom_rdd;
+	struct ramoops_platform_data *pdata;
+	struct reserved_mem *rmem;
+	struct device_node *node;
+	long ret;
+
+	node = of_parse_phandle(of_node, "memory-region", 0);
+	if (!node)
+		return -ENODEV;
+
+	rmem = of_reserved_mem_lookup(node);
+	of_node_put(node);
+	if (!rmem) {
+		dev_err(&pdev->dev, "failed to locate DT /reserved-memory resource\n");
+		return -EINVAL;
+	}
+
+	qcom_rdd = devm_kzalloc(&pdev->dev, sizeof(*qcom_rdd), GFP_KERNEL);
+	if (!qcom_rdd)
+		return -ENOMEM;
+
+	pdata = &qcom_rdd->qcom_ramoops_pdata;
+	pdata->mem_size = rmem->size;
+	pdata->mem_address = rmem->base;
+	ramoops_parse_dt(pdev, pdata);
+
+	qcom_rdd->ramoops_pdev = platform_device_register_data(NULL, "ramoops", -1,
+							       pdata, sizeof(*pdata));
+	if (IS_ERR(qcom_rdd->ramoops_pdev)) {
+		ret = PTR_ERR(qcom_rdd->ramoops_pdev);
+		dev_err(&pdev->dev, "could not create platform device: %ld\n", ret);
+		qcom_rdd->ramoops_pdev = NULL;
+	}
+	platform_set_drvdata(pdev, qcom_rdd);
+
+	return ret;
+}
+
+static void qcom_ramoops_remove(struct platform_device *pdev)
+{
+	struct qcom_ramoops_dd *qcom_rdd = platform_get_drvdata(pdev);
+
+	platform_device_unregister(qcom_rdd->ramoops_pdev);
+	qcom_rdd->ramoops_pdev = NULL;
+}
+
+static const struct of_device_id qcom_ramoops_of_match[] = {
+	{ .compatible = "qcom,ramoops"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_ramoops_of_match);
+
+static struct platform_driver qcom_ramoops_drv = {
+	.driver		= {
+		.name	= "qcom,ramoops",
+		.of_match_table = qcom_ramoops_of_match,
+	},
+	.probe = qcom_ramoops_probe,
+	.remove_new = qcom_ramoops_remove,
+};
+
+module_platform_driver(qcom_ramoops_drv);
+
+MODULE_DESCRIPTION("Qualcomm ramoops minidump driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4