net: ipa: introduce sysfs code

Add IPA device attributes to expose information known by the IPA
driver about the hardware and its configuration.

All pointers used to display these attribute values (i.e., IPA
pointer and endpoint pointers) will have been initialized by the
time IPA probe has completed, so they may be safely dereferenced.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/ABI/testing/sysfs-devices-platform-soc-ipa

+What:		/sys/devices/platform/soc@X/XXXXXXX.ipa/
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The /sys/devices/platform/soc@X/XXXXXXX.ipa/ directory
+		contains read-only attributes exposing information about
+		an IPA device.  The X values could vary, but are typically
+		"soc@0/1e40000.ipa".
+
+What:		.../XXXXXXX.ipa/version
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The .../XXXXXXX.ipa/version file contains the IPA hardware
+		version, as a period-separated set of two or three integers
+		(e.g., "3.5.1" or "4.2").
+
+What:		.../XXXXXXX.ipa/feature/
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The .../XXXXXXX.ipa/feature/ directory contains a set of
+		attributes describing features implemented by the IPA
+		hardware.
+
+What:		.../XXXXXXX.ipa/feature/rx_offload
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The .../XXXXXXX.ipa/feature/rx_offload file contains a
+		string indicating the type of receive checksum offload
+		that is supported by the hardware.  The possible values
+		are "MAPv4" or "MAPv5".
+
+What:		.../XXXXXXX.ipa/feature/tx_offload
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The .../XXXXXXX.ipa/feature/tx_offload file contains a
+		string indicating the type of transmit checksum offload
+		that is supported by the hardware.  The possible values
+		are "MAPv4" or "MAPv5".
+
+What:		.../XXXXXXX.ipa/modem/
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The .../XXXXXXX.ipa/modem/ directory contains a set of
+		attributes describing properties of the modem execution
+		environment reachable by the IPA hardware.
+
+What:		.../XXXXXXX.ipa/modem/rx_endpoint_id
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The .../XXXXXXX.ipa/feature/rx_endpoint_id file contains
+		the AP endpoint ID that receives packets originating from
+		the modem execution environment.  The "rx" is from the
+		perspective of the AP; this endpoint is considered an "IPA
+		producer".  An endpoint ID is a small unsigned integer.
+
+What:		.../XXXXXXX.ipa/modem/tx_endpoint_id
+Date:		June 2021
+KernelVersion:	v5.14
+Contact:	Alex Elder <elder@kernel.org>
+Description:
+		The .../XXXXXXX.ipa/feature/tx_endpoint_id file contains
+		the AP endpoint ID used to transmit packets destined for
+		the modem execution environment.  The "tx" is from the
+		perspective of the AP; this endpoint is considered an "IPA
+		consumer".  An endpoint ID is a small unsigned integer.

drivers/net/ipa/Makefile

@@ -7,7 +7,8 @@ ipa-y			:=	ipa_main.o ipa_clock.o ipa_reg.o ipa_mem.o \
 				ipa_table.o ipa_interrupt.o gsi.o gsi_trans.o \
 				ipa_gsi.o ipa_smp2p.o ipa_uc.o \
 				ipa_endpoint.o ipa_cmd.o ipa_modem.o \
-				ipa_resource.o ipa_qmi.o ipa_qmi_msg.o
+				ipa_resource.o ipa_qmi.o ipa_qmi_msg.o \
+				ipa_sysfs.o
 
 ipa-y			+=	ipa_data-v3.5.1.o ipa_data-v4.2.o \
 				ipa_data-v4.5.o ipa_data-v4.9.o \

drivers/net/ipa/ipa_main.c

@@ -31,6 +31,7 @@
 #include "ipa_uc.h"
 #include "ipa_interrupt.h"
 #include "gsi_trans.h"
+#include "ipa_sysfs.h"
 
 /**
  * DOC: The IP Accelerator
@@ -906,6 +907,13 @@ static const struct dev_pm_ops ipa_pm_ops = {
 	.resume		= ipa_resume,
 };
 
+static const struct attribute_group *ipa_attribute_groups[] = {
+	&ipa_attribute_group,
+	&ipa_feature_attribute_group,
+	&ipa_modem_attribute_group,
+	NULL,
+};
+
 static struct platform_driver ipa_driver = {
 	.probe		= ipa_probe,
 	.remove		= ipa_remove,
@@ -914,6 +922,7 @@ static struct platform_driver ipa_driver = {
 		.name		= "ipa",
 		.pm		= &ipa_pm_ops,
 		.of_match_table	= ipa_match,
+		.dev_groups	= ipa_attribute_groups,
 	},
 };
 

drivers/net/ipa/ipa_sysfs.c

+// SPDX-License-Identifier: GPL-2.0
+
+/* Copyright (C) 2021 Linaro Ltd. */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/sysfs.h>
+
+#include "ipa.h"
+#include "ipa_version.h"
+#include "ipa_sysfs.h"
+
+static const char *ipa_version_string(struct ipa *ipa)
+{
+	switch (ipa->version) {
+	case IPA_VERSION_3_0:
+		return "3.0";
+	case IPA_VERSION_3_1:
+		return "3.1";
+	case IPA_VERSION_3_5:
+		return "3.5";
+	case IPA_VERSION_3_5_1:
+		return "3.5.1";
+	case IPA_VERSION_4_0:
+		return "4.0";
+	case IPA_VERSION_4_1:
+		return "4.1";
+	case IPA_VERSION_4_2:
+		return "4.2";
+	case IPA_VERSION_4_5:
+		return "4.5";
+	case IPA_VERSION_4_7:
+		return "4.7";
+	case IPA_VERSION_4_9:
+		return "4.9";
+	case IPA_VERSION_4_11:
+		return "4.11";
+	default:
+		return "0.0";	/* Won't happen (checked at probe time) */
+	}
+}
+
+static ssize_t
+version_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", ipa_version_string(ipa));
+}
+
+static DEVICE_ATTR_RO(version);
+
+static struct attribute *ipa_attrs[] = {
+	&dev_attr_version.attr,
+	NULL
+};
+
+const struct attribute_group ipa_attribute_group = {
+	.attrs		= ipa_attrs,
+};
+
+static const char *ipa_offload_string(struct ipa *ipa)
+{
+	return ipa->version < IPA_VERSION_4_5 ? "MAPv4" : "MAPv5";
+}
+
+static ssize_t rx_offload_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", ipa_offload_string(ipa));
+}
+
+static DEVICE_ATTR_RO(rx_offload);
+
+static ssize_t tx_offload_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s\n", ipa_offload_string(ipa));
+}
+
+static DEVICE_ATTR_RO(tx_offload);
+
+static struct attribute *ipa_feature_attrs[] = {
+	&dev_attr_rx_offload.attr,
+	&dev_attr_tx_offload.attr,
+	NULL
+};
+
+const struct attribute_group ipa_feature_attribute_group = {
+	.name		= "feature",
+	.attrs		= ipa_feature_attrs,
+};
+
+static ssize_t
+ipa_endpoint_id_show(struct ipa *ipa, char *buf, enum ipa_endpoint_name name)
+{
+	u32 endpoint_id = ipa->name_map[name]->endpoint_id;
+
+	return scnprintf(buf, PAGE_SIZE, "%u\n", endpoint_id);
+}
+
+static ssize_t rx_endpoint_id_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+
+	return ipa_endpoint_id_show(ipa, buf, IPA_ENDPOINT_AP_MODEM_RX);
+}
+
+static DEVICE_ATTR_RO(rx_endpoint_id);
+
+static ssize_t tx_endpoint_id_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct ipa *ipa = dev_get_drvdata(dev);
+
+	return ipa_endpoint_id_show(ipa, buf, IPA_ENDPOINT_AP_MODEM_TX);
+}
+
+static DEVICE_ATTR_RO(tx_endpoint_id);
+
+static struct attribute *ipa_modem_attrs[] = {
+	&dev_attr_rx_endpoint_id.attr,
+	&dev_attr_tx_endpoint_id.attr,
+	NULL
+};
+
+const struct attribute_group ipa_modem_attribute_group = {
+	.name		= "modem",
+	.attrs		= ipa_modem_attrs,
+};

drivers/net/ipa/ipa_sysfs.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Copyright (c) 2012-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2019-2021 Linaro Ltd.
+ */
+#ifndef _IPA_SYSFS_H_
+#define _IPA_SYSFS_H_
+
+struct attribute_group;
+
+extern const struct attribute_group ipa_attribute_group;
+extern const struct attribute_group ipa_feature_attribute_group;
+extern const struct attribute_group ipa_modem_attribute_group;
+
+#endif /* _IPA_SYSFS_H_ */

drivers/net/ipa/ipa_version.h

@@ -21,6 +21,8 @@
  * @IPA_VERSION_4_11:	IPA version 4.11/GSI version 2.11 (2.1.1)
  *
  * Defines the version of IPA (and GSI) hardware present on the platform.
+ * Please update ipa_version_valid() and ipa_version_string() whenever a
+ * new version is added.
  */
 enum ipa_version {
 	IPA_VERSION_3_0,