[PATCH v2] arm: mvebu: Espressobin: Set environment variable fdtfile

[Andre Heider <a.heider@gmail.com>]

Required for the generic distro mechanism.

Linux ships with 4 variants:
marvell/armada-3720-espressobin-v7-emmc.dtb
marvell/armada-3720-espressobin-v7.dtb
marvell/armada-3720-espressobin-emmc.dtb
marvell/armada-3720-espressobin.dtb

Use available information to determine the appropriate filename.

Fixes booting GRUB EFI arm64 on Fedora.

Reported-by: Dennis Gilmore <dennis@ausil.us>
Signed-off-by: Andre Heider <a.heider@gmail.com>
---

v2:
- enable BOARD_LATE_INIT only for espressobin, via defconfig
- don't overwrite a set/saved $fdtfile

This still has the issue that $fdtfile doesn't show up after `env
default -a`. Pali may look into that, but the infrastructure for it
needs to be created first.

Until then, this can be considered as v2010.10 material as it fixes
booting distros relying on $fdtfile.

Tested myself on a v5 board without eMMC.
Tested by G?rald on v7 emmc, v7/ddr4 detection confirmed working.

 board/Marvell/mvebu_armada-37xx/board.c     | 47 +++++++++++++++++++++
 configs/mvebu_espressobin-88f3720_defconfig |  1 +
 2 files changed, 48 insertions(+)

diff --git a/board/Marvell/mvebu_armada-37xx/board.c b/board/Marvell/mvebu_armada-37xx/board.c
index 90bfc139aa..73d69e0388 100644
--- a/board/Marvell/mvebu_armada-37xx/board.c
+++ b/board/Marvell/mvebu_armada-37xx/board.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <env.h>
 #include <i2c.h>
 #include <init.h>
 #include <phy.h>
@@ -50,6 +51,22 @@ DECLARE_GLOBAL_DATA_PTR;
 #define MVEBU_G2_SMI_PHY_CMD_REG	(24)
 #define MVEBU_G2_SMI_PHY_DATA_REG	(25)
 
+/*
+ * Memory Controller Registers
+ *
+ * Assembled based on public information:
+ * https://gitlab.nic.cz/turris/mox-boot-builder/-/blob/master/wtmi/main.c#L332-336
+ * https://github.com/MarvellEmbeddedProcessors/mv-ddr-marvell/blob/mv_ddr-armada-18.12/drivers/mv_ddr_mc6.h#L309-L332
+ *
+ * And checked against the written register values for the various topologies:
+ * https://github.com/MarvellEmbeddedProcessors/mv-ddr-marvell/blob/mv_ddr-armada-atf-mainline/a3700/mv_ddr_tim.h
+ */
+#define A3700_CH0_MC_CTRL2_REG		MVEBU_REGISTER(0x002c4)
+#define A3700_MC_CTRL2_SDRAM_TYPE_MASK	0xf
+#define A3700_MC_CTRL2_SDRAM_TYPE_OFFS	4
+#define A3700_MC_CTRL2_SDRAM_TYPE_DDR3	2
+#define A3700_MC_CTRL2_SDRAM_TYPE_DDR4	3
+
 int board_early_init_f(void)
 {
 	return 0;
@@ -63,6 +80,36 @@ int board_init(void)
 	return 0;
 }
 
+#ifdef CONFIG_BOARD_LATE_INIT
+int board_late_init(void)
+{
+	bool ddr4, emmc;
+
+	if (env_get("fdtfile"))
+		return 0;
+
+	if (!of_machine_is_compatible("globalscale,espressobin"))
+		return 0;
+
+	/* If the memory controller has been configured for DDR4, we're running on v7 */
+	ddr4 = ((readl(A3700_CH0_MC_CTRL2_REG) >> A3700_MC_CTRL2_SDRAM_TYPE_OFFS)
+		& A3700_MC_CTRL2_SDRAM_TYPE_MASK) == A3700_MC_CTRL2_SDRAM_TYPE_DDR4;
+
+	emmc = of_machine_is_compatible("globalscale,espressobin-emmc");
+
+	if (ddr4 && emmc)
+		env_set("fdtfile", "marvell/armada-3720-espressobin-v7-emmc.dtb");
+	else if (ddr4)
+		env_set("fdtfile", "marvell/armada-3720-espressobin-v7.dtb");
+	else if (emmc)
+		env_set("fdtfile", "marvell/armada-3720-espressobin-emmc.dtb");
+	else
+		env_set("fdtfile", "marvell/armada-3720-espressobin.dtb");
+
+	return 0;
+}
+#endif
+
 /* Board specific AHCI / SATA enable code */
 int board_ahci_enable(void)
 {
diff --git a/configs/mvebu_espressobin-88f3720_defconfig b/configs/mvebu_espressobin-88f3720_defconfig
index 5e9fcd1f26..559aeb076f 100644
--- a/configs/mvebu_espressobin-88f3720_defconfig
+++ b/configs/mvebu_espressobin-88f3720_defconfig
@@ -85,3 +85,4 @@ CONFIG_USB_ETHER_SMSC95XX=y
 CONFIG_SHA1=y
 CONFIG_SHA256=y
 CONFIG_NET_RANDOM_ETHADDR=y
+CONFIG_BOARD_LATE_INIT=y
-- 
2.28.0