[XS] Change in coreboot[main]: mb/siemens/mc_ehl2: Limit eMMC speed mode to DDR50

[Werner Zeh (Code Review)]

Werner Zeh has submitted this change. ( https://review.coreboot.org/c/coreboot/+/85881?usp=email )

(

2 is the latest approved patch-set.
No files were changed between the latest approved patch-set and the submitted one.
 )Change subject: mb/siemens/mc_ehl2: Limit eMMC speed mode to DDR50
......................................................................

mb/siemens/mc_ehl2: Limit eMMC speed mode to DDR50

Due to layout restrictions on mc_ehl2, the eMMC interface is limited to
operate in DDR50 mode. The alternative modes SDR104 and SDR50 are not
supported. Limit the capabilities in the eMMC controller to DDR50 mode
only so that the eMMC driver in OS will choose the right mode for
operation even if the attached eMMC card supports higher modes.

BUG=none
TEST=Boot into Linux and check dmesg output for mmc modes

Change-Id: I668bb5b0b3197497920b36bcf283c25d2a0c00ba
Signed-off-by: Mario Scheithauer 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/85881
Reviewed-by: Uwe Poeche 
Reviewed-by: Werner Zeh 
Tested-by: build bot (Jenkins) 
---
M src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c
1 file changed, 9 insertions(+), 0 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Werner Zeh: Looks good to me, approved
  Uwe Poeche: Looks good to me, but someone else must approve

diff --git a/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c b/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c
index dd90d6f..ac3ab14 100644
--- a/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c
+++ b/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c
@@ -50,6 +50,15 @@
    	/* Use preset driver strength from preset value registers. */
    	clrsetbits16(res2mmio(res, HOSTCTRL2, 0), 0, HOSTCTRL2_PRESET);
    }
+
+	dev = pcidev_path_on_root(PCH_DEVFN_EMMC);
+	if (dev) {
+		struct resource *res = probe_resource(dev, PCI_BASE_ADDRESS_0);
+		if (!res)
+			return;
+
+		disable_sdr_modes(res);
+	}
 }

static void finalize_boot(void *unused)