New patch to review for coreboot: sb/amd/sp5100: Add enable_ehci_async_data_cache CMOS option

[Timothy Pearson]

Timothy Pearson ([e-mail]) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/14241

-gerrit

commit a0046d91ab2b6d72bd2186f7c8f3890081da62ac
Author: Timothy Pearson 
Date:   Mon Apr 4 14:24:23 2016 -0500

sb/amd/sp5100: Add enable_ehci_async_data_cache CMOS option

SP5100 devices are affected by an erratum that can lock up the
    EHCI ports under certain conditions.  Add an optional CMOS
    option to enable the workaround at the expense of performance.

Change-Id: I305d23dfa50f10a3dcb5c731e8923305c8956dde
    Signed-off-by: Timothy Pearson 
---
 src/southbridge/amd/sb700/usb.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/southbridge/amd/sb700/usb.c b/src/southbridge/amd/sb700/usb.c
index cd7378e..7d82f05 100644
--- a/src/southbridge/amd/sb700/usb.c
+++ b/src/southbridge/amd/sb700/usb.c
@@ -76,10 +76,16 @@ static void usb_init(struct device *dev)

static void usb_init2(struct device *dev)
 {
-	u32 dword;
+	uint32_t dword;
    void *usb2_bar0;
    device_t sm_dev;
-	u8 rev;
+	uint8_t rev;
+	uint8_t ehci_async_data_cache;
+	uint8_t nvram;
+
+	ehci_async_data_cache = 1;
+	if (get_option(&nvram, "enable_ehci_async_data_cache") == CB_SUCCESS)
+		ehci_async_data_cache = !!nvram;

sm_dev = dev_find_slot(0, PCI_DEVFN(0x14, 0));
    rev = get_sb700_revision(sm_dev);
@@ -174,6 +180,12 @@ static void usb_init2(struct device *dev)
    	dword |= 1 << 8;
    	dword &= ~(1 << 27); /* 6.23 */
    }
+#if CONFIG_SOUTHBRIDGE_AMD_SUBTYPE_SP5100
+	/* SP5100 Erratum 36 */
+	dword &= ~(1 << 26);
+	if (!ehci_async_data_cache)
+		dword |= 1 << 26;
+#endif
    pci_write_config32(dev, 0x50, dword);
    printk(BIOS_DEBUG, "rpr 6.23, final dword=%x\n", dword);
 }