1 files changed, 344 insertions, 0 deletions
diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
new file mode 100644
index 0000000000..7020584096
--- /dev/null
+++ b/drivers/acpi/prmt.c
@@ -0,0 +1,344 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Author: Erik Kaneda <erik.kaneda@intel.com>
+ * Copyright 2020 Intel Corporation
+ *
+ * prmt.c
+ *
+ * Each PRM service is an executable that is run in a restricted environment
+ * that is invoked by writing to the PlatformRtMechanism OperationRegion from
+ * AML bytecode.
+ *
+ * init_prmt initializes the Platform Runtime Mechanism (PRM) services by
+ * processing data in the PRMT as well as registering an ACPI OperationRegion
+ * handler for the PlatformRtMechanism subtype.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/efi.h>
+#include <linux/acpi.h>
+#include <linux/prmt.h>
+#include <asm/efi.h>
+
+#pragma pack(1)
+struct prm_mmio_addr_range {
+	u64 phys_addr;
+	u64 virt_addr;
+	u32 length;
+};
+
+struct prm_mmio_info {
+	u64 mmio_count;
+	struct prm_mmio_addr_range addr_ranges[];
+};
+
+struct prm_buffer {
+	u8 prm_status;
+	u64 efi_status;
+	u8 prm_cmd;
+	guid_t handler_guid;
+};
+
+struct prm_context_buffer {
+	char signature[ACPI_NAMESEG_SIZE];
+	u16 revision;
+	u16 reserved;
+	guid_t identifier;
+	u64 static_data_buffer;
+	struct prm_mmio_info *mmio_ranges;
+};
+#pragma pack()
+
+static LIST_HEAD(prm_module_list);
+
+struct prm_handler_info {
+	guid_t guid;
+	efi_status_t (__efiapi *handler_addr)(u64, void *);
+	u64 static_data_buffer_addr;
+	u64 acpi_param_buffer_addr;
+
+	struct list_head handler_list;
+};
+
+struct prm_module_info {
+	guid_t guid;
+	u16 major_rev;
+	u16 minor_rev;
+	u16 handler_count;
+	struct prm_mmio_info *mmio_info;
+	bool updatable;
+
+	struct list_head module_list;
+	struct prm_handler_info handlers[];
+};
+
+static u64 efi_pa_va_lookup(u64 pa)
+{
+	efi_memory_desc_t *md;
+	u64 pa_offset = pa & ~PAGE_MASK;
+	u64 page = pa & PAGE_MASK;
+
+	for_each_efi_memory_desc(md) {
+		if (md->phys_addr < pa && pa < md->phys_addr + PAGE_SIZE * md->num_pages)
+			return pa_offset + md->virt_addr + page - md->phys_addr;
+	}
+
+	return 0;
+}
+
+#define get_first_handler(a) ((struct acpi_prmt_handler_info *) ((char *) (a) + a->handler_info_offset))
+#define get_next_handler(a) ((struct acpi_prmt_handler_info *) (sizeof(struct acpi_prmt_handler_info) + (char *) a))
+
+static int __init
+acpi_parse_prmt(union acpi_subtable_headers *header, const unsigned long end)
+{
+	struct acpi_prmt_module_info *module_info;
+	struct acpi_prmt_handler_info *handler_info;
+	struct prm_handler_info *th;
+	struct prm_module_info *tm;
+	u64 *mmio_count;
+	u64 cur_handler = 0;
+	u32 module_info_size = 0;
+	u64 mmio_range_size = 0;
+	void *temp_mmio;
+
+	module_info = (struct acpi_prmt_module_info *) header;
+	module_info_size = struct_size(tm, handlers, module_info->handler_info_count);
+	tm = kmalloc(module_info_size, GFP_KERNEL);
+	if (!tm)
+		goto parse_prmt_out1;
+
+	guid_copy(&tm->guid, (guid_t *) module_info->module_guid);
+	tm->major_rev = module_info->major_rev;
+	tm->minor_rev = module_info->minor_rev;
+	tm->handler_count = module_info->handler_info_count;
+	tm->updatable = true;
+
+	if (module_info->mmio_list_pointer) {
+		/*
+		 * Each module is associated with a list of addr
+		 * ranges that it can use during the service
+		 */
+		mmio_count = (u64 *) memremap(module_info->mmio_list_pointer, 8, MEMREMAP_WB);
+		if (!mmio_count)
+			goto parse_prmt_out2;
+
+		mmio_range_size = struct_size(tm->mmio_info, addr_ranges, *mmio_count);
+		tm->mmio_info = kmalloc(mmio_range_size, GFP_KERNEL);
+		if (!tm->mmio_info)
+			goto parse_prmt_out3;
+
+		temp_mmio = memremap(module_info->mmio_list_pointer, mmio_range_size, MEMREMAP_WB);
+		if (!temp_mmio)
+			goto parse_prmt_out4;
+		memmove(tm->mmio_info, temp_mmio, mmio_range_size);
+	} else {
+		tm->mmio_info = kmalloc(sizeof(*tm->mmio_info), GFP_KERNEL);
+		if (!tm->mmio_info)
+			goto parse_prmt_out2;
+
+		tm->mmio_info->mmio_count = 0;
+	}
+
+	INIT_LIST_HEAD(&tm->module_list);
+	list_add(&tm->module_list, &prm_module_list);
+
+	handler_info = get_first_handler(module_info);
+	do {
+		th = &tm->handlers[cur_handler];
+
+		guid_copy(&th->guid, (guid_t *)handler_info->handler_guid);
+		th->handler_addr = (void *)efi_pa_va_lookup(handler_info->handler_address);
+		th->static_data_buffer_addr = efi_pa_va_lookup(handler_info->static_data_buffer_address);
+		th->acpi_param_buffer_addr = efi_pa_va_lookup(handler_info->acpi_param_buffer_address);
+	} while (++cur_handler < tm->handler_count && (handler_info = get_next_handler(handler_info)));
+
+	return 0;
+
+parse_prmt_out4:
+	kfree(tm->mmio_info);
+parse_prmt_out3:
+	memunmap(mmio_count);
+parse_prmt_out2:
+	kfree(tm);
+parse_prmt_out1:
+	return -ENOMEM;
+}
+
+#define GET_MODULE	0
+#define GET_HANDLER	1
+
+static void *find_guid_info(const guid_t *guid, u8 mode)
+{
+	struct prm_handler_info *cur_handler;
+	struct prm_module_info *cur_module;
+	int i = 0;
+
+	list_for_each_entry(cur_module, &prm_module_list, module_list) {
+		for (i = 0; i < cur_module->handler_count; ++i) {
+			cur_handler = &cur_module->handlers[i];
+			if (guid_equal(guid, &cur_handler->guid)) {
+				if (mode == GET_MODULE)
+					return (void *)cur_module;
+				else
+					return (void *)cur_handler;
+			}
+		}
+	}
+
+	return NULL;
+}
+
+static struct prm_module_info *find_prm_module(const guid_t *guid)
+{
+	return (struct prm_module_info *)find_guid_info(guid, GET_MODULE);
+}
+
+static struct prm_handler_info *find_prm_handler(const guid_t *guid)
+{
+	return (struct prm_handler_info *) find_guid_info(guid, GET_HANDLER);
+}
+
+/* In-coming PRM commands */
+
+#define PRM_CMD_RUN_SERVICE		0
+#define PRM_CMD_START_TRANSACTION	1
+#define PRM_CMD_END_TRANSACTION		2
+
+/* statuses that can be passed back to ASL */
+
+#define PRM_HANDLER_SUCCESS 		0
+#define PRM_HANDLER_ERROR 		1
+#define INVALID_PRM_COMMAND 		2
+#define PRM_HANDLER_GUID_NOT_FOUND 	3
+#define UPDATE_LOCK_ALREADY_HELD 	4
+#define UPDATE_UNLOCK_WITHOUT_LOCK 	5
+
+/*
+ * This is the PlatformRtMechanism opregion space handler.
+ * @function: indicates the read/write. In fact as the PlatformRtMechanism
+ * message is driven by command, only write is meaningful.
+ *
+ * @addr   : not used
+ * @bits   : not used.
+ * @value  : it is an in/out parameter. It points to the PRM message buffer.
+ * @handler_context: not used
+ */
+static acpi_status acpi_platformrt_space_handler(u32 function,
+						 acpi_physical_address addr,
+						 u32 bits, acpi_integer *value,
+						 void *handler_context,
+						 void *region_context)
+{
+	struct prm_buffer *buffer = ACPI_CAST_PTR(struct prm_buffer, value);
+	struct prm_handler_info *handler;
+	struct prm_module_info *module;
+	efi_status_t status;
+	struct prm_context_buffer context;
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+		pr_err_ratelimited("PRM: EFI runtime services no longer available\n");
+		return AE_NO_HANDLER;
+	}
+
+	/*
+	 * The returned acpi_status will always be AE_OK. Error values will be
+	 * saved in the first byte of the PRM message buffer to be used by ASL.
+	 */
+	switch (buffer->prm_cmd) {
+	case PRM_CMD_RUN_SERVICE:
+
+		handler = find_prm_handler(&buffer->handler_guid);
+		module = find_prm_module(&buffer->handler_guid);
+		if (!handler || !module)
+			goto invalid_guid;
+
+		ACPI_COPY_NAMESEG(context.signature, "PRMC");
+		context.revision = 0x0;
+		context.reserved = 0x0;
+		context.identifier = handler->guid;
+		context.static_data_buffer = handler->static_data_buffer_addr;
+		context.mmio_ranges = module->mmio_info;
+
+		status = efi_call_acpi_prm_handler(handler->handler_addr,
+						   handler->acpi_param_buffer_addr,
+						   &context);
+		if (status == EFI_SUCCESS) {
+			buffer->prm_status = PRM_HANDLER_SUCCESS;
+		} else {
+			buffer->prm_status = PRM_HANDLER_ERROR;
+			buffer->efi_status = status;
+		}
+		break;
+
+	case PRM_CMD_START_TRANSACTION:
+
+		module = find_prm_module(&buffer->handler_guid);
+		if (!module)
+			goto invalid_guid;
+
+		if (module->updatable)
+			module->updatable = false;
+		else
+			buffer->prm_status = UPDATE_LOCK_ALREADY_HELD;
+		break;
+
+	case PRM_CMD_END_TRANSACTION:
+
+		module = find_prm_module(&buffer->handler_guid);
+		if (!module)
+			goto invalid_guid;
+
+		if (module->updatable)
+			buffer->prm_status = UPDATE_UNLOCK_WITHOUT_LOCK;
+		else
+			module->updatable = true;
+		break;
+
+	default:
+
+		buffer->prm_status = INVALID_PRM_COMMAND;
+		break;
+	}
+
+	return AE_OK;
+
+invalid_guid:
+	buffer->prm_status = PRM_HANDLER_GUID_NOT_FOUND;
+	return AE_OK;
+}
+
+void __init init_prmt(void)
+{
+	struct acpi_table_header *tbl;
+	acpi_status status;
+	int mc;
+
+	status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
+	if (ACPI_FAILURE(status))
+		return;
+
+	mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
+					  sizeof (struct acpi_table_prmt_header),
+					  0, acpi_parse_prmt, 0);
+	acpi_put_table(tbl);
+	/*
+	 * Return immediately if PRMT table is not present or no PRM module found.
+	 */
+	if (mc <= 0)
+		return;
+
+	pr_info("PRM: found %u modules\n", mc);
+
+	if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
+		pr_err("PRM: EFI runtime services unavailable\n");
+		return;
+	}
+
+	status = acpi_install_address_space_handler(ACPI_ROOT_OBJECT,
+						    ACPI_ADR_SPACE_PLATFORM_RT,
+						    &acpi_platformrt_space_handler,
+						    NULL, NULL);
+	if (ACPI_FAILURE(status))
+		pr_alert("PRM: OperationRegion handler could not be installed\n");
+}