From 83b776137399bcfa9427e7a60d5f1620ee2d1985 Mon Sep 17 00:00:00 2001 From: Timothy Pearson Date: Thu, 18 Jun 2015 11:48:02 -0500 Subject: southbridge/amd/sb700: Add option to disable SATA ALPM The AMD Register Programming Reference states that the user should have the option to disable Active Link Power Management for two reasons. First, some drives may not function correctly with the ALPM implementation of the SP5100, and second there are some situations where low latency access is more important than the power savings created by using ALPM. Allow the user to disable ALPM if desired. Change-Id: I88055cbb4df4d7ba811cef7056c0a6ca2612fcb0 Signed-off-by: Timothy Pearson Reviewed-on: http://review.coreboot.org/11993 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer --- src/southbridge/amd/sb700/sata.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'src/southbridge') diff --git a/src/southbridge/amd/sb700/sata.c b/src/southbridge/amd/sb700/sata.c index fdf32c780e..c61fa01953 100644 --- a/src/southbridge/amd/sb700/sata.c +++ b/src/southbridge/amd/sb700/sata.c @@ -104,6 +104,7 @@ static void sata_init(struct device *dev) int i, j; uint8_t nvram; uint8_t sata_ahci_mode; + uint8_t sata_alpm_enable; uint8_t port_count; uint8_t max_port_count; @@ -111,6 +112,10 @@ static void sata_init(struct device *dev) if (get_option(&nvram, "sata_ahci_mode") == CB_SUCCESS) sata_ahci_mode = !!nvram; + sata_alpm_enable = 0; + if (get_option(&nvram, "sata_alpm") == CB_SUCCESS) + sata_alpm_enable = !!nvram; + device_t sm_dev; /* SATA SMBus Disable */ sm_dev = dev_find_slot(0, PCI_DEVFN(0x14, 0)); @@ -229,6 +234,13 @@ static void sata_init(struct device *dev) dword &= ~(0x1 << i); write32(sata_bar5 + 0x0c, dword); + /* Disable ALPM if ALPM support not requested */ + if (!sata_alpm_enable) { + dword = read32(sata_bar5 + 0xfc); + dword &= ~(0x1 << 11); /* Disable ALPM */ + write32(sata_bar5 + 0xfc, dword); + } + /* Write protect Sub-Class Code */ byte = pci_read_config8(dev, 0x40); byte &= ~(1 << 0); -- cgit v1.2.3