driver: Google EFI SMI

The "gsmi" driver bridges userland with firmware specific routines for
accessing hardware.

Currently, this driver only supports NVRAM and eventlog information.
Deprecated functions have been removed from the driver, though their
op-codes are left in place so that they are not re-used.

This driver works by trampolining into the firmware via the smi_command
outlined in the FADT table.  Three protocols are used due to various
limitations over time, but all are included herein.

This driver should only ever load on Google boards, identified by either
a "Google, Inc." board vendor string in DMI, or "GOOGLE" in the OEM
strings of the FADT ACPI table.  This logic happens in
gsmi_system_valid().

Signed-off-by: Duncan Laurie <dlaurie@google.com>
Signed-off-by: Aaron Durbin <adurbin@google.com>
Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

5 files changed, 955 insertions, 0 deletions

diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index b3a25a55ba23..efba163595db 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -157,4 +157,6 @@ config SIGMA
           If unsure, say N here.  Drivers that need these helpers will select
           this option automatically.
 
+source "drivers/firmware/google/Kconfig"
+
 endmenu
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 00bb0b80a79f..d7d600992d4a 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -13,3 +13,5 @@ obj-$(CONFIG_ISCSI_IBFT_FIND)	+= iscsi_ibft_find.o
 obj-$(CONFIG_ISCSI_IBFT)        += iscsi_ibft.o
 obj-$(CONFIG_FIRMWARE_MEMMAP)   += memmap.o
 obj-$(CONFIG_SIGMA)             += sigma.o
+
+obj-y  += google/
diff --git a/drivers/firmware/google/Kconfig b/drivers/firmware/google/Kconfig
new file mode 100644
index 000000000000..4a0383537f5d
--- /dev/null
+++ b/drivers/firmware/google/Kconfig
@@ -0,0 +1,9 @@
+config GOOGLE_SMI
+        tristate "SMI interface for Google platforms"
+        depends on ACPI && DMI
+        select EFI_VARS
+        help
+          Say Y here if you want to enable SMI callbacks for Google
+          platforms.  This provides an interface for writing to and
+          clearing the EFI event log and reading and writing NVRAM
+          variables.
diff --git a/drivers/firmware/google/Makefile b/drivers/firmware/google/Makefile
new file mode 100644
index 000000000000..fb127d7b3c7a
--- /dev/null
+++ b/drivers/firmware/google/Makefile
@@ -0,0 +1,2 @@
+
+obj-$(CONFIG_GOOGLE_SMI)                += gsmi.o
diff --git a/drivers/firmware/google/gsmi.c b/drivers/firmware/google/gsmi.c
new file mode 100644
index 000000000000..fa7f0b3e81dd
--- /dev/null
+++ b/drivers/firmware/google/gsmi.c
@@ -0,0 +1,940 @@
+/*
+ * Copyright 2010 Google Inc. All Rights Reserved.
+ * Author: dlaurie@google.com (Duncan Laurie)
+ *
+ * Re-worked to expose sysfs APIs by mikew@google.com (Mike Waychison)
+ *
+ * EFI SMI interface for Google platforms
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/ioctl.h>
+#include <linux/acpi.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <linux/dmi.h>
+#include <linux/kdebug.h>
+#include <linux/reboot.h>
+#include <linux/efi.h>
+
+#define GSMI_SHUTDOWN_CLEAN     0       /* Clean Shutdown */
+/* TODO(mikew@google.com): Tie in HARDLOCKUP_DETECTOR with NMIWDT */
+#define GSMI_SHUTDOWN_NMIWDT    1       /* NMI Watchdog */
+#define GSMI_SHUTDOWN_PANIC     2       /* Panic */
+#define GSMI_SHUTDOWN_OOPS      3       /* Oops */
+#define GSMI_SHUTDOWN_DIE       4       /* Die -- No longer meaningful */
+#define GSMI_SHUTDOWN_MCE       5       /* Machine Check */
+#define GSMI_SHUTDOWN_SOFTWDT   6       /* Software Watchdog */
+#define GSMI_SHUTDOWN_MBE       7       /* Uncorrected ECC */
+#define GSMI_SHUTDOWN_TRIPLE    8       /* Triple Fault */
+
+#define DRIVER_VERSION          "1.0"
+#define GSMI_GUID_SIZE          16
+#define GSMI_BUF_SIZE           1024
+#define GSMI_BUF_ALIGN          sizeof(u64)
+#define GSMI_CALLBACK           0xef
+
+/* SMI return codes */
+#define GSMI_SUCCESS            0x00
+#define GSMI_UNSUPPORTED2       0x03
+#define GSMI_LOG_FULL           0x0b
+#define GSMI_VAR_NOT_FOUND      0x0e
+#define GSMI_HANDSHAKE_SPIN     0x7d
+#define GSMI_HANDSHAKE_CF       0x7e
+#define GSMI_HANDSHAKE_NONE     0x7f
+#define GSMI_INVALID_PARAMETER  0x82
+#define GSMI_UNSUPPORTED        0x83
+#define GSMI_BUFFER_TOO_SMALL   0x85
+#define GSMI_NOT_READY          0x86
+#define GSMI_DEVICE_ERROR       0x87
+#define GSMI_NOT_FOUND          0x8e
+
+#define QUIRKY_BOARD_HASH 0x78a30a50
+
+/* Internally used commands passed to the firmware */
+#define GSMI_CMD_GET_NVRAM_VAR          0x01
+#define GSMI_CMD_GET_NEXT_VAR           0x02
+#define GSMI_CMD_SET_NVRAM_VAR          0x03
+#define GSMI_CMD_SET_EVENT_LOG          0x08
+#define GSMI_CMD_CLEAR_EVENT_LOG        0x09
+#define GSMI_CMD_CLEAR_CONFIG           0x20
+#define GSMI_CMD_HANDSHAKE_TYPE         0xC1
+
+/* Magic entry type for kernel events */
+#define GSMI_LOG_ENTRY_TYPE_KERNEL     0xDEAD
+
+/* SMI buffers must be in 32bit physical address space */
+struct gsmi_buf {
+        u8 *start;                      /* start of buffer */
+        size_t length;                  /* length of buffer */
+        dma_addr_t handle;              /* dma allocation handle */
+        u32 address;                    /* physical address of buffer */
+};
+
+struct gsmi_device {
+        struct platform_device *pdev;   /* platform device */
+        struct gsmi_buf *name_buf;      /* variable name buffer */
+        struct gsmi_buf *data_buf;      /* generic data buffer */
+        struct gsmi_buf *param_buf;     /* parameter buffer */
+        spinlock_t lock;                /* serialize access to SMIs */
+        u16 smi_cmd;                    /* SMI command port */
+        int handshake_type;             /* firmware handler interlock type */
+        struct dma_pool *dma_pool;      /* DMA buffer pool */
+} gsmi_dev;
+
+/* Packed structures for communicating with the firmware */
+struct gsmi_nvram_var_param {
+        efi_guid_t      guid;
+        u32             name_ptr;
+        u32             attributes;
+        u32             data_len;
+        u32             data_ptr;
+} __packed;
+
+struct gsmi_get_next_var_param {
+        u8      guid[GSMI_GUID_SIZE];
+        u32     name_ptr;
+        u32     name_len;
+} __packed;
+
+struct gsmi_set_eventlog_param {
+        u32     data_ptr;
+        u32     data_len;
+        u32     type;
+} __packed;
+
+/* Event log formats */
+struct gsmi_log_entry_type_1 {
+        u16     type;
+        u32     instance;
+} __packed;
+
+
+/*
+ * Some platforms don't have explicit SMI handshake
+ * and need to wait for SMI to complete.
+ */
+#define GSMI_DEFAULT_SPINCOUNT  0x10000
+static unsigned int spincount = GSMI_DEFAULT_SPINCOUNT;
+module_param(spincount, uint, 0600);
+MODULE_PARM_DESC(spincount,
+        "The number of loop iterations to use when using the spin handshake.");
+
+static struct gsmi_buf *gsmi_buf_alloc(void)
+{
+        struct gsmi_buf *smibuf;
+
+        smibuf = kzalloc(sizeof(*smibuf), GFP_KERNEL);
+        if (!smibuf) {
+                printk(KERN_ERR "gsmi: out of memory\n");
+                return NULL;
+        }
+
+        /* allocate buffer in 32bit address space */
+        smibuf->start = dma_pool_alloc(gsmi_dev.dma_pool, GFP_KERNEL,
+                                       &smibuf->handle);
+        if (!smibuf->start) {
+                printk(KERN_ERR "gsmi: failed to allocate name buffer\n");
+                kfree(smibuf);