cros_ec: Add vstore support

The EC can store small amounts of data for the benefit of the
verified boot process. Since the EC is seldom reset, this can allow the
AP to store data that survives a reboot or a suspend/resume cycle.

Add support for this.

Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 121 insertions, 2 deletions

diff --git a/drivers/misc/cros_ec.c b/drivers/misc/cros_ec.c
index c22bb4b..ebfa7c4 100644
--- a/drivers/misc/cros_ec.c
+++ b/drivers/misc/cros_ec.c
@@ -1557,6 +1557,77 @@ int cros_ec_set_lid_shutdown_mask(struct udevice *dev, int enable)
 	return 0;
 }
 
+int cros_ec_vstore_supported(struct udevice *dev)
+{
+	return cros_ec_check_feature(dev, EC_FEATURE_VSTORE);
+}
+
+int cros_ec_vstore_info(struct udevice *dev, u32 *lockedp)
+{
+	struct ec_response_vstore_info *resp;
+
+	if (ec_command_inptr(dev, EC_CMD_VSTORE_INFO, 0, NULL, 0,
+			     (uint8_t **)&resp, sizeof(*resp)) != sizeof(*resp))
+		return -EIO;
+
+	if (lockedp)
+		*lockedp = resp->slot_locked;
+
+	return resp->slot_count;
+}
+
+/*
+ * cros_ec_vstore_read - Read data from EC vstore slot
+ *
+ * @slot: vstore slot to read from
+ * @data: buffer to store read data, must be EC_VSTORE_SLOT_SIZE bytes
+ */
+int cros_ec_vstore_read(struct udevice *dev, int slot, uint8_t *data)
+{
+	struct ec_params_vstore_read req;
+	struct ec_response_vstore_read *resp;
+
+	req.slot = slot;
+	if (ec_command_inptr(dev, EC_CMD_VSTORE_READ, 0, &req, sizeof(req),
+			     (uint8_t **)&resp, sizeof(*resp)) != sizeof(*resp))
+		return -EIO;
+
+	if (!data || req.slot >= EC_VSTORE_SLOT_MAX)
+		return -EINVAL;
+
+	memcpy(data, resp->data, sizeof(resp->data));
+
+	return 0;
+}
+
+/*
+ * cros_ec_vstore_write - Save data into EC vstore slot
+ *
+ * @slot: vstore slot to write into
+ * @data: data to write
+ * @size: size of data in bytes
+ *
+ * Maximum size of data is EC_VSTORE_SLOT_SIZE.  It is the callers
+ * responsibility to check the number of implemented slots by
+ * querying the vstore info.
+ */
+int cros_ec_vstore_write(struct udevice *dev, int slot, const uint8_t *data,
+			 size_t size)
+{
+	struct ec_params_vstore_write req;
+
+	if (slot >= EC_VSTORE_SLOT_MAX || size > EC_VSTORE_SLOT_SIZE)
+		return -EINVAL;
+
+	req.slot = slot;
+	memcpy(req.data, data, size);
+
+	if (ec_command(dev, EC_CMD_VSTORE_WRITE, 0, &req, sizeof(req), NULL, 0))
+		return -EIO;
+
+	return 0;
+}
+
 int cros_ec_get_switches(struct udevice *dev)
 {
 	struct dm_cros_ec_ops *ops;
diff --git a/drivers/misc/cros_ec_sandbox.c b/drivers/misc/cros_ec_sandbox.c
index 845876c..cb8adc4 100644
--- a/drivers/misc/cros_ec_sandbox.c
+++ b/drivers/misc/cros_ec_sandbox.c
@@ -62,6 +62,15 @@ struct ec_keymatrix_entry {
 	int keycode;	/* corresponding linux key code */
 };
 
+enum {
+	VSTORE_SLOT_COUNT	= 4,
+};
+
+struct vstore_slot {
+	bool locked;
+	u8 data[EC_VSTORE_SLOT_SIZE];
+};
+
 /**
  * struct ec_state - Information about the EC state
  *
@@ -75,7 +84,7 @@ struct ec_keymatrix_entry {
  * @keyscan: Current keyscan information (bit set for each row/column pressed)
  * @recovery_req: Keyboard recovery requested
  * @test_flags: Flags that control behaviour for tests
- * @switches: Current switches value (EC_SWITCH_)
+ * @slot_locked: Locked vstore slots (mask)
  */
 struct ec_state {
 	u8 vbnv_context[EC_VBNV_BLOCK_SIZE_V2];
@@ -88,6 +97,7 @@ struct ec_state {
 	uint8_t keyscan[KEYBOARD_COLS];
 	bool recovery_req;
 	uint test_flags;
+	struct vstore_slot slot[VSTORE_SLOT_COUNT];
 } s_state, *g_state;
 
 /**
@@ -495,13 +505,51 @@ static int process_cmd(struct ec_state *ec,
 		struct ec_response_get_features *resp = resp_data;
 
 		resp->flags[0] = EC_FEATURE_MASK_0(EC_FEATURE_FLASH) |
-			EC_FEATURE_MASK_0(EC_FEATURE_I2C);
+			EC_FEATURE_MASK_0(EC_FEATURE_I2C) |
+			EC_FEATURE_MASK_0(EC_FEATURE_VSTORE);
 		resp->flags[1] =
 			EC_FEATURE_MASK_1(EC_FEATURE_UNIFIED_WAKE_MASKS) |
 			EC_FEATURE_MASK_1(EC_FEATURE_ISH);
 		len = sizeof(*resp);
 		break;
 	}
+	case EC_CMD_VSTORE_INFO: {
+		struct ec_response_vstore_info *resp = resp_data;
+		int i;
+
+		resp->slot_count = VSTORE_SLOT_COUNT;
+		resp->slot_locked = 0;
+		for (i = 0; i < VSTORE_SLOT_COUNT; i++) {
+			if (ec->slot[i].locked)
+				resp->slot_locked |= 1 << i;
+		}
+		len = sizeof(*resp);
+		break;
+	};
+	case EC_CMD_VSTORE_WRITE: {
+		const struct ec_params_vstore_write *req = req_data;
+		struct vstore_slot *slot;
+
+		if (req->slot >= EC_VSTORE_SLOT_MAX)
+			return -EINVAL;
+		slot = &ec->slot[req->slot];
+		slot->locked = true;
+		memcpy(slot->data, req->data, EC_VSTORE_SLOT_SIZE);
+		len = 0;
+		break;
+	}
+	case EC_CMD_VSTORE_READ: {
+		const struct ec_params_vstore_read *req = req_data;
+		struct ec_response_vstore_read *resp = resp_data;
+		struct vstore_slot *slot;
+
+		if (req->slot >= EC_VSTORE_SLOT_MAX)
+			return -EINVAL;
+		slot = &ec->slot[req->slot];
+		memcpy(resp->data, slot->data, EC_VSTORE_SLOT_SIZE);
+		len = sizeof(*resp);
+		break;
+	}
 	default:
 		printf("   ** Unknown EC command %#02x\n", req_hdr->command);
 		return -1;