broadwell: Fix PCIe ports programming sequences to enable HSIOPC

HSIOPC/GPIO71 is used to control power to VCCHSIO, VCCUSB3PLL and
VCCSATA3PLL in S0. PCH will drive HSIOPC low when all the high
speed I/O controllers (xHCI, SATA, GbE and PCIe) are idle.

This patch added a few additional PCIe programming steps as required
in 535127 BIOS Writer Guide Rev 2.3.0 to enable this power saving mode.

BUG=none
BRANCH=none
TEST=tested on Paine watching GPIO71 toggling as expected

Change-Id: Ica6954c125ec3129e2659168f1f23dc861ce5708
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Original-Commit-Id: e38f9ef57c480ca5ee420020eb80a1adb3c381d3
Original-Change-Id: I88ef125c681c8631e8b887f7ccf017b90b8c0f10
Original-Signed-off-by: Wenkai Du <wenkai.du@intel.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/238580
Original-Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/9482
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

2 files changed, 33 insertions, 5 deletions

diff --git a/src/soc/intel/broadwell/pcie.c b/src/soc/intel/broadwell/pcie.c
index bb237be..4476fe4 100644
--- a/src/soc/intel/broadwell/pcie.c
+++ b/src/soc/intel/broadwell/pcie.c
@@ -32,6 +32,7 @@
 #include <soc/rcba.h>
 #include <soc/intel/broadwell/chip.h>
 #include <soc/cpu.h>
+#include <delay.h>
 
 static void pcie_update_cfg8(device_t dev, int reg, u8 mask, u8 or);
 static void pcie_update_cfg(device_t dev, int reg, u32 mask, u32 or);
@@ -300,6 +301,7 @@ static void root_port_commit_config(void)
 	for (i = 0; i < rpc.num_ports; i++) {
 		device_t dev;
 		u32 reg32;
+		int n = 0;
 
 		dev = rpc.ports[i];
 
@@ -313,11 +315,22 @@ static void root_port_commit_config(void)
 
 		printk(BIOS_DEBUG, "%s: Disabling device\n",  dev_path(dev));
 
-		/* Ensure memory, io, and bus master are all disabled */
-		reg32 = pci_read_config32(dev, PCI_COMMAND);
-		reg32 &= ~(PCI_COMMAND_MASTER |
-			   PCI_COMMAND_MEMORY | PCI_COMMAND_IO);
-		pci_write_config32(dev, PCI_COMMAND, reg32);
+		/* 8.2 Configuration of PCI Express Root Ports */
+		pcie_update_cfg(dev, 0x338, ~(1 << 26), 1 << 26);
+
+		do {
+			reg32 = pci_read_config32(dev, 0x328);
+			n++;
+			if (((reg32 & 0xff000000) == 0x01000000) || (n > 500))
+				break;
+			udelay(100);
+		} while (1);
+
+		if (n > 500)
+			printk(BIOS_DEBUG, "%s: Timeout waiting for 328h\n",
+				dev_path(dev));
+
+		pcie_update_cfg(dev, 0x408, ~(1 << 27), 1 << 27);
 
 		/* Disable this device if possible */
 		pch_disable_devfn(dev);
diff --git a/src/soc/intel/broadwell/romstage/pch.c b/src/soc/intel/broadwell/romstage/pch.c
index f31e6ba..6fa6c39 100644
--- a/src/soc/intel/broadwell/romstage/pch.c
+++ b/src/soc/intel/broadwell/romstage/pch.c
@@ -135,6 +135,16 @@ static void pch_enable_lpc(void)
 	pci_write_config32(PCH_DEV_LPC, LPC_GEN4_DEC, config->gen4_dec);
 }
 
+static void pcie_update_cfg(device_t dev, int reg, u32 mask, u32 or)
+{
+	u32 reg32;
+
+	reg32 = pci_read_config32(dev, reg);
+	reg32 &= mask;
+	reg32 |= or;
+	pci_write_config32(dev, reg, reg32);
+}
+
 void pch_early_init(void)
 {
 	reg_script_run_on_dev(PCH_DEV_LPC, pch_early_init_script);
@@ -143,4 +153,9 @@ void pch_early_init(void)
 	pch_enable_lpc();
 
 	enable_smbus();
+
+	/* 8.14 Additional PCI Express Programming Steps, step #1 */
+	pcie_update_cfg(_PCH_DEV(PCIE, 0), 0xf4, ~0x60, 0);
+	pcie_update_cfg(_PCH_DEV(PCIE, 0), 0xf4, ~0x80, 0x80);
+	pcie_update_cfg(_PCH_DEV(PCIE, 0), 0xe2, ~0x30, 0x30);
 }