[coreboot-gerrit] [S] Change in coreboot[master]: mb/siemens/mc_ehl2: Use preset driver strength for SD-Card

[Mario Scheithauer (Code Review)]

Mario Scheithauer has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/68166 )

Change subject: mb/siemens/mc_ehl2: Use preset driver strength for SD-Card
......................................................................

mb/siemens/mc_ehl2: Use preset driver strength for SD-Card

The intention of predefining driver strength is to avoid that the OS
SD-Card driver changes this setting.

Change-Id: I02fdac94462da1cd77f8dc972faf16f28d94c946
Signed-off-by: Mario Scheithauer 
---
M src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c
1 file changed, 21 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/66/68166/1

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 a798398..3395160 100644
--- a/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c
+++ b/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/mainboard.c
@@ -9,6 +9,8 @@
 #include <soc/pci_devs.h>
 #include <soc/pcr_ids.h>

+#define HOSTCTRL2		0x3E
+#define  HOSTCTRL2_PRESET	(1 << 15)
 #define SD_CAP_BYP		0x810
 #define  SD_CAP_BYP_EN		0x5A
 #define SD_CAP_BYP_REG1		0x814
@@ -34,6 +36,7 @@
    dev = pcidev_path_on_root(PCH_DEVFN_SDCARD);
    if (dev) {
    	uint32_t reg;
+		uint16_t reg16;
    	struct resource *res = probe_resource(dev, PCI_BASE_ADDRESS_0);
    	if (!res)
    		return;
@@ -43,6 +46,11 @@
    	reg &= ~(SD_CAP_BYP_SDR104 | SD_CAP_BYP_SDR50);
    	reg |= SD_CAP_BYP_DDR50;
    	write32(res2mmio(res, SD_CAP_BYP_REG1, 0), reg);
+
+		/* Use preset driver strength from preset value registers. */
+		reg16 = read16(res2mmio(res, HOSTCTRL2, 0));
+		reg16 |= HOSTCTRL2_PRESET;
+		write16(res2mmio(res, HOSTCTRL2, 0), reg16);
    }
 }