From 5fe2215bc5196d836b54e1e5fb00b63fa096fda7 Mon Sep 17 00:00:00 2001 From: Leah Rowe Date: Thu, 1 May 2025 15:46:54 +0100 Subject: [PATCH 4/4] ahci: Only reset controller on CSM Please refer to this commit: commit 8863cbbd15a73b03153553c562f5b1fb939ad4d7 Author: Gerd Hoffmann Date: Thu Feb 6 12:10:21 2025 +0100 ahci: add controller reset This commit broke AHCI init on the Lenovo ThinkPad T420, when tested with SeaBIOS as a coreboot payload. Since the above commit was made with CSMs in mind, to make the AHCI driver work there, that change has been re-worked so as to only apply when a CSM is in use. Signed-off-by: Leah Rowe --- src/hw/ahci.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/src/hw/ahci.c b/src/hw/ahci.c index 2285d33d..b09b198a 100644 --- a/src/hw/ahci.c +++ b/src/hw/ahci.c @@ -637,7 +637,7 @@ static void ahci_controller_setup(struct pci_device *pci) { struct ahci_port_s *port; - u32 pnr, max; + u32 val, pnr, max; if (create_bounce_buf() < 0) return; @@ -660,8 +660,19 @@ ahci_controller_setup(struct pci_device *pci) pci_enable_busmaster(pci); - ahci_ctrl_writel(ctrl, HOST_CTL, HOST_CTL_RESET); - ahci_ctrl_writel(ctrl, HOST_CTL, HOST_CTL_AHCI_EN); + /* AHCI controller reset, but only for CSM. Commit 8863cbbd + introduced this universally, to make AHCI drivers work in + CSM mode, but it broke AHCI setup on the ThinkPad T420 when + SeaBIOS is used as a coreboot payload, hence the else clause: */ + if (CONFIG_CSM) { + /* Enable AHCI controller after resetting its state */ + ahci_ctrl_writel(ctrl, HOST_CTL, HOST_CTL_RESET); + ahci_ctrl_writel(ctrl, HOST_CTL, HOST_CTL_AHCI_EN); + } else { + /* Enable AHCI controller from its current state */ + val = ahci_ctrl_readl(ctrl, HOST_CTL); + ahci_ctrl_writel(ctrl, HOST_CTL, val | HOST_CTL_AHCI_EN); + } ctrl->caps = ahci_ctrl_readl(ctrl, HOST_CAP); ctrl->ports = ahci_ctrl_readl(ctrl, HOST_PORTS_IMPL); -- 2.39.5