[PATCH v2 1/4] platform/x86: simatic-ipc: add main driver for Siemens devices

[Henning Schild <henning.schild@siemens.com>]

This mainly implements detection of these devices and will allow
secondary drivers to work on such machines.

The identification is DMI-based with a vendor specific way to tell them
apart in a reliable way.

Drivers for LEDs and Watchdogs will follow to make use of that platform
detection.

Signed-off-by: Henning Schild <henning.schild@siemens.com>
---
 drivers/platform/x86/Kconfig                  |  12 ++
 drivers/platform/x86/Makefile                 |   3 +
 drivers/platform/x86/simatic-ipc.c            | 168 ++++++++++++++++++
 .../platform_data/x86/simatic-ipc-base.h      |  29 +++
 include/linux/platform_data/x86/simatic-ipc.h |  66 +++++++
 5 files changed, 278 insertions(+)
 create mode 100644 drivers/platform/x86/simatic-ipc.c
 create mode 100644 include/linux/platform_data/x86/simatic-ipc-base.h
 create mode 100644 include/linux/platform_data/x86/simatic-ipc.h

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index ad4e630e73e2..44f8e82e1fd9 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1284,6 +1284,18 @@ config INTEL_TELEMETRY
 	  directly via debugfs files. Various tools may use
 	  this interface for SoC state monitoring.
 
+config SIEMENS_SIMATIC_IPC
+	tristate "Siemens Simatic IPC Class driver"
+	depends on PCI
+	help
+	  This Simatic IPC class driver is the central of several drivers. It
+	  is mainly used for system identification, after which drivers in other
+	  classes will take care of driving specifics of those machines.
+	  i.e. LEDs and watchdog.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called simatic-ipc.
+
 endif # X86_PLATFORM_DEVICES
 
 config PMC_ATOM
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 60d554073749..26cdebf2e701 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -138,3 +138,6 @@ obj-$(CONFIG_INTEL_TELEMETRY)		+= intel_telemetry_core.o \
 					   intel_telemetry_pltdrv.o \
 					   intel_telemetry_debugfs.o
 obj-$(CONFIG_PMC_ATOM)			+= pmc_atom.o
+
+# Siemens Simatic Industrial PCs
+obj-$(CONFIG_SIEMENS_SIMATIC_IPC)	+= simatic-ipc.o
diff --git a/drivers/platform/x86/simatic-ipc.c b/drivers/platform/x86/simatic-ipc.c
new file mode 100644
index 000000000000..7c32c12ad32d
--- /dev/null
+++ b/drivers/platform/x86/simatic-ipc.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Siemens SIMATIC IPC platform driver
+ *
+ * Copyright (c) Siemens AG, 2018-2021
+ *
+ * Authors:
+ *  Henning Schild <henning.schild@siemens.com>
+ *  Jan Kiszka <jan.kiszka@siemens.com>
+ *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/dmi.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_data/x86/simatic-ipc.h>
+#include <linux/platform_device.h>
+
+static struct platform_device *ipc_led_platform_device;
+static struct platform_device *ipc_wdt_platform_device;
+
+static const struct dmi_system_id simatic_ipc_whitelist[] = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "SIEMENS AG"),
+		},
+	},
+	{}
+};
+
+static struct simatic_ipc_platform platform_data;
+
+static struct {
+	u32 station_id;
+	u8 led_mode;
+	u8 wdt_mode;
+} device_modes[] = {
+	{SIMATIC_IPC_IPC127E, SIMATIC_IPC_DEVICE_127E, SIMATIC_IPC_DEVICE_NONE},
+	{SIMATIC_IPC_IPC227D, SIMATIC_IPC_DEVICE_227D, SIMATIC_IPC_DEVICE_NONE},
+	{SIMATIC_IPC_IPC227E, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_227E},
+	{SIMATIC_IPC_IPC277E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_227E},
+	{SIMATIC_IPC_IPC427D, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_NONE},
+	{SIMATIC_IPC_IPC427E, SIMATIC_IPC_DEVICE_427E, SIMATIC_IPC_DEVICE_427E},
+	{SIMATIC_IPC_IPC477E, SIMATIC_IPC_DEVICE_NONE, SIMATIC_IPC_DEVICE_427E},
+};
+
+static int register_platform_devices(u32 station_id)
+{
+	u8 ledmode = SIMATIC_IPC_DEVICE_NONE;
+	u8 wdtmode = SIMATIC_IPC_DEVICE_NONE;
+	int i;
+
+	platform_data.devmode = SIMATIC_IPC_DEVICE_NONE;
+
+	for (i = 0; i < ARRAY_SIZE(device_modes); i++) {
+		if (device_modes[i].station_id == station_id) {
+			ledmode = device_modes[i].led_mode;
+			wdtmode = device_modes[i].wdt_mode;
+			break;
+		}
+	}
+
+	if (ledmode != SIMATIC_IPC_DEVICE_NONE) {
+		platform_data.devmode = ledmode;
+		ipc_led_platform_device =
+			platform_device_register_data(NULL,
+				KBUILD_MODNAME "_leds", PLATFORM_DEVID_NONE,
+				&platform_data,
+				sizeof(struct simatic_ipc_platform));
+		if (IS_ERR(ipc_led_platform_device))
+			return PTR_ERR(ipc_led_platform_device);
+
+		pr_debug("device=%s created\n",
+			 ipc_led_platform_device->name);
+	}
+
+	if (wdtmode != SIMATIC_IPC_DEVICE_NONE) {
+		platform_data.devmode = wdtmode;
+		ipc_wdt_platform_device =
+			platform_device_register_data(NULL,
+				KBUILD_MODNAME "_wdt", PLATFORM_DEVID_NONE,
+				&platform_data,
+				sizeof(struct simatic_ipc_platform));
+		if (IS_ERR(ipc_wdt_platform_device))
+			return PTR_ERR(ipc_wdt_platform_device);
+
+		pr_debug("device=%s created\n",
+			 ipc_wdt_platform_device->name);
+	}
+
+	if (ledmode == SIMATIC_IPC_DEVICE_NONE &&
+	    wdtmode == SIMATIC_IPC_DEVICE_NONE) {
+		pr_warn("unsupported IPC detected, station id=%08x\n",
+			station_id);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
+ * Get membase address from PCI, used in leds and wdt modul. Here we read
+ * the bar0. The final address calculation is done in the appropriate modules
+ */
+
+u32 simatic_ipc_get_membase0(unsigned int p2sb)
+{
+	struct pci_bus *bus;
+	u32 bar0 = 0;
+
+	/*
+	 * The GPIO memory is bar0 of the hidden P2SB device. Unhide the device
+	 * to have a quick look at it, before we hide it again.
+	 * Also grab the pci rescan lock so that device does not get discovered
+	 * and remapped while it is visible.
+	 * This code is inspired by drivers/mfd/lpc_ich.c
+	 */
+	bus = pci_find_bus(0, 0);
+	pci_lock_rescan_remove();
+	pci_bus_write_config_byte(bus, p2sb, 0xE1, 0x0);
+	pci_bus_read_config_dword(bus, p2sb, PCI_BASE_ADDRESS_0, &bar0);
+
+	bar0 &= ~0xf;
+	pci_bus_write_config_byte(bus, p2sb, 0xE1, 0x1);
+	pci_unlock_rescan_remove();
+
+	return bar0;
+}
+EXPORT_SYMBOL(simatic_ipc_get_membase0);
+
+static int __init simatic_ipc_init_module(void)
+{
+	const struct dmi_system_id *match;
+	u32 station_id;
+	int err;
+
+	match = dmi_first_match(simatic_ipc_whitelist);
+	if (!match)
+		return 0;
+
+	err = dmi_walk(simatic_ipc_find_dmi_entry_helper, &station_id);
+
+	if (err || station_id == SIMATIC_IPC_INVALID_STATION_ID) {
+		pr_warn("DMI entry %d not found\n", DMI_ENTRY_OEM);
+		return 0;
+	}
+
+	return register_platform_devices(station_id);
+}
+
+static void __exit simatic_ipc_exit_module(void)
+{
+	platform_device_unregister(ipc_led_platform_device);
+	ipc_led_platform_device = NULL;
+
+	platform_device_unregister(ipc_wdt_platform_device);
+	ipc_wdt_platform_device = NULL;
+}
+
+module_init(simatic_ipc_init_module);
+module_exit(simatic_ipc_exit_module);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");
+MODULE_ALIAS("dmi:*:svnSIEMENSAG:*");
diff --git a/include/linux/platform_data/x86/simatic-ipc-base.h b/include/linux/platform_data/x86/simatic-ipc-base.h
new file mode 100644
index 000000000000..62d2bc774067
--- /dev/null
+++ b/include/linux/platform_data/x86/simatic-ipc-base.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Siemens SIMATIC IPC drivers
+ *
+ * Copyright (c) Siemens AG, 2018-2021
+ *
+ * Authors:
+ *  Henning Schild <henning.schild@siemens.com>
+ *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
+ */
+
+#ifndef __PLATFORM_DATA_X86_SIMATIC_IPC_BASE_H
+#define __PLATFORM_DATA_X86_SIMATIC_IPC_BASE_H
+
+#include <linux/types.h>
+
+#define SIMATIC_IPC_DEVICE_NONE 0
+#define SIMATIC_IPC_DEVICE_227D 1
+#define SIMATIC_IPC_DEVICE_427E 2
+#define SIMATIC_IPC_DEVICE_127E 3
+#define SIMATIC_IPC_DEVICE_227E 4
+
+struct simatic_ipc_platform {
+	u8	devmode;
+};
+
+u32 simatic_ipc_get_membase0(unsigned int p2sb);
+
+#endif /* __PLATFORM_DATA_X86_SIMATIC_IPC_BASE_H */
diff --git a/include/linux/platform_data/x86/simatic-ipc.h b/include/linux/platform_data/x86/simatic-ipc.h
new file mode 100644
index 000000000000..3af84a84f103
--- /dev/null
+++ b/include/linux/platform_data/x86/simatic-ipc.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Siemens SIMATIC IPC drivers
+ *
+ * Copyright (c) Siemens AG, 2018-2021
+ *
+ * Authors:
+ *  Henning Schild <henning.schild@siemens.com>
+ *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
+ */
+
+#ifndef __PLATFORM_DATA_X86_SIMATIC_IPC_H
+#define __PLATFORM_DATA_X86_SIMATIC_IPC_H
+
+#include <linux/dmi.h>
+#include <linux/platform_data/x86/simatic-ipc-base.h>
+
+#define DMI_ENTRY_OEM	129
+
+enum ipc_station_ids {
+	SIMATIC_IPC_INVALID_STATION_ID = 0,
+	SIMATIC_IPC_IPC227D = 0x00000501,
+	SIMATIC_IPC_IPC427D = 0x00000701,
+	SIMATIC_IPC_IPC227E = 0x00000901,
+	SIMATIC_IPC_IPC277E = 0x00000902,
+	SIMATIC_IPC_IPC427E = 0x00000A01,
+	SIMATIC_IPC_IPC477E = 0x00000A02,
+	SIMATIC_IPC_IPC127E = 0x00000D01,
+};
+
+static inline u32 simatic_ipc_get_station_id(u8 *data, int max_len)
+{
+	u32 station_id = SIMATIC_IPC_INVALID_STATION_ID;
+	int i;
+	struct {
+		u8	type;		/* type (0xff = binary) */
+		u8	len;		/* len of data entry */
+		u8	reserved[3];
+		u32	station_id;	/* station id (LE) */
+	} __packed
+	*data_entry = (void *)data + sizeof(struct dmi_header);
+
+	/* find 4th entry in OEM data */
+	for (i = 0; i < 3; i++)
+		data_entry = (void *)((u8 *)(data_entry) + data_entry->len);
+
+	/* decode station id */
+	if (data_entry && (u8 *)data_entry < data + max_len &&
+	    data_entry->type == 0xff && data_entry->len == 9)
+		station_id = le32_to_cpu(data_entry->station_id);
+
+	return station_id;
+}
+
+static inline void
+simatic_ipc_find_dmi_entry_helper(const struct dmi_header *dh, void *_data)
+{
+	u32 *id = _data;
+
+	if (dh->type != DMI_ENTRY_OEM)
+		return;
+
+	*id = simatic_ipc_get_station_id((u8 *)dh, dh->length);
+}
+
+#endif /* __PLATFORM_DATA_X86_SIMATIC_IPC_H */
-- 
2.26.2