New patch to review for coreboot: 2cb3e3b lynxpoint: Do not put SerialIO devices into D3Hot in ACPI mode

[Duncan Laurie]

Duncan Laurie ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/5193

-gerrit

commit 2cb3e3b828285dc7b390d7af1a2917bb9fa6af3f
Author: Duncan Laurie 
Date:   Tue Feb 11 10:34:06 2014 -0800

lynxpoint: Do not put SerialIO devices into D3Hot in ACPI mode

Remove the bit of code that was putting the SerialIO devices into
    D3Hot state when they are switched from PCI to ACPI mode.  Instead,
    add the appropriate ACPI Methods to allow the kernel to control the
    power state of the device.

The problem seems to be that if the device is put in D3Hot state
    before it is switched from PCI to ACPI mode then it does not properly
    export its PCI configuration space and cannot be woken back up.

Adding the ACPI Methods for _PS0/_PS3 allows the kernel to transition
    the device into D0 state only when it is necessary to communicate with
    the device, then put it back into D3Hot state.

Change-Id: I2384ba10bf47750d1c1a35216169ddeee26881df
    Signed-off-by: Duncan Laurie 
---
 src/southbridge/intel/lynxpoint/acpi/serialio.asl | 44 +++++++++++++++++++++++
 src/southbridge/intel/lynxpoint/serialio.c        | 10 ------
 2 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/src/southbridge/intel/lynxpoint/acpi/serialio.asl b/src/southbridge/intel/lynxpoint/acpi/serialio.asl
index 4c0d36b..59228d6 100644
--- a/src/southbridge/intel/lynxpoint/acpi/serialio.asl
+++ b/src/southbridge/intel/lynxpoint/acpi/serialio.asl
@@ -211,6 +211,28 @@ Device (I2C0)
    		Return (0xF)
    	}
    }
+
+	// Access to PCI Config in ACPI mode
+	OperationRegion (KEYS, SystemMemory, \S1B1, 0x100)
+	Field (KEYS, DWordAcc, NoLock, Preserve)
+	{
+		Offset (0x84),
+		PSAT, 32,
+	}
+
+	// Put controller in D0 state
+	Method (_PS0, 0, Serialized)
+	{
+		And (^PSAT, 0xfffffffc, ^PSAT)
+		Store (^PSAT, Local0)
+	}
+
+	// Put controller in D3Hot state
+	Method (_PS3, 0, Serialized)
+	{
+		Or (^PSAT, 0x00000003, ^PSAT)
+		Store (^PSAT, Local0)
+	}
 }

Device (I2C1)
@@ -262,6 +284,28 @@ Device (I2C1)
    		Return (0xF)
    	}
    }
+
+	// Access to PCI Config in ACPI mode
+	OperationRegion (KEYS, SystemMemory, \S2B1, 0x100)
+	Field (KEYS, DWordAcc, NoLock, Preserve)
+	{
+		Offset (0x84),
+		PSAT, 32,
+	}
+
+	// Put controller in D0 state
+	Method (_PS0, 0, Serialized)
+	{
+		And (^PSAT, 0xfffffffc, ^PSAT)
+		Store (^PSAT, Local0)
+	}
+
+	// Put controller in D3Hot state
+	Method (_PS3, 0, Serialized)
+	{
+		Or (^PSAT, 0x00000003, ^PSAT)
+		Store (^PSAT, Local0)
+	}
 }

Device (SPI0)
diff --git a/src/southbridge/intel/lynxpoint/serialio.c b/src/southbridge/intel/lynxpoint/serialio.c
index 8257cc2..75edf5c 100644
--- a/src/southbridge/intel/lynxpoint/serialio.c
+++ b/src/southbridge/intel/lynxpoint/serialio.c
@@ -29,14 +29,6 @@
 #include "pch.h"
 #include "nvs.h"

-/* Set D3Hot Power State in ACPI mode */
-static void serialio_enable_d3hot(struct device *dev)
-{
-	u32 reg32 = pci_read_config32(dev, PCH_PCS);
-	reg32 |= PCH_PCS_PS_D3HOT;
-	pci_write_config32(dev, PCH_PCS, reg32);
-}
-
 /* Enable clock in PCI mode */
 static void serialio_enable_clock(struct resource *bar0)
 {
@@ -178,8 +170,6 @@ static void serialio_init(struct device *dev)

if (!config->sio_acpi_mode)
    	serialio_enable_clock(bar0);
-	else if (dev->path.pci.devfn != PCI_DEVFN(21, 0))
-		serialio_enable_d3hot(dev); /* all but SDMA */

switch (dev->path.pci.devfn) {
    case PCI_DEVFN(21, 0): /* SDMA */