From 647ed5cf33945ee43686fa1405281161d2a92b2f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thi=C3=A9baud=20Weksteen?= <tweek@google.com>
Date: Sat, 10 Sep 2016 09:06:26 +0200
Subject: [PATCH] Check that hardware sequencing is enabled (#86)

---
 source/tool/chipsec/hal/spi.py            | 16 ++++++++++++++++
 source/tool/tests/software/mock_helper.py |  3 +++
 2 files changed, 19 insertions(+)

diff --git a/source/tool/chipsec/hal/spi.py b/source/tool/chipsec/hal/spi.py
index 5b1d59c4..1bc4b727 100644
--- a/source/tool/chipsec/hal/spi.py
+++ b/source/tool/chipsec/hal/spi.py
@@ -480,6 +480,13 @@ class SPI:
 
         return cycle_done
 
+    def check_hardware_sequencing(self):
+        # Test if the flash decriptor is valid (and hardware sequencing enabled)
+        fdv = chipsec.chipset.read_register_field(self.cs, 'HSFS', 'FDV')
+        if fdv == 0:
+            logger().error("HSFS.FDV is 0, hardware sequencing is disabled")
+            raise SpiRuntimeError("Chipset does not support hardware sequencing")
+
     #
     # SPI Flash operations
     #
@@ -500,6 +507,9 @@ class SPI:
         #return self.write_spi( spi_fla, struct.unpack('B'*len(buf), buf) )
 
     def read_spi(self, spi_fla, data_byte_count ):
+
+        self.check_hardware_sequencing()
+	
         buf = []
         dbc = SPI_READ_WRITE_DEF_DBC
         if (data_byte_count >= SPI_READ_WRITE_MAX_DBC):
@@ -550,6 +560,9 @@ class SPI:
         return buf
 
     def write_spi(self, spi_fla, buf ):
+	
+        self.check_hardware_sequencing()
+
         write_ok = True
         data_byte_count = len(buf)
         dbc = 4
@@ -590,6 +603,9 @@ class SPI:
         return write_ok
 
     def erase_spi_block(self, spi_fla ):
+
+        self.check_hardware_sequencing()
+
         if logger().UTIL_TRACE or logger().VERBOSE:
             logger().log( "[spi] Erasing SPI Flash block @ 0x%X" % spi_fla )
 
diff --git a/source/tool/tests/software/mock_helper.py b/source/tool/tests/software/mock_helper.py
index abb22ecf..31b3912f 100644
--- a/source/tool/tests/software/mock_helper.py
+++ b/source/tool/tests/software/mock_helper.py
@@ -194,6 +194,7 @@ class SPIHelper(TestHelper):
     RCBA_ADDR = 0xFED0000
     SPIBAR_ADDR = RCBA_ADDR + 0x3800
     SPIBAR_END = SPIBAR_ADDR + 0x200
+    HSFS = SPIBAR_ADDR + 0x4
     FRAP = SPIBAR_ADDR + 0x50
     FREG0 = SPIBAR_ADDR + 0x54
     LPC_BRIDGE_DEVICE = (0, 0x1F, 0)
@@ -218,6 +219,8 @@ class SPIHelper(TestHelper):
             return 0x00020002
         elif pa == self.FRAP:
             return 0xEEEEEEEE
+        elif pa == self.HSFS:
+            return (1 << 14) # FDV = 1, the flash descriptor is valid
         elif pa >= self.SPIBAR_ADDR and pa < self.SPIBAR_END:
             return 0x0
         else: