arm: mvebu: turris_omnia: Fixup SATA or PCIe nodes at runtime in DT blob

On of the MiniPCIe ports on Turris Omnia is also a mSATA port. Whether
it works in SATA or PCIe mode is determined by a strapping pin, which
value is read from the MCU.

We already determine which type of card is connected when configuring
SerDeses.

But until now we left both SATA and PCIe port 0 nodes in device tree
enabled, and so the SATA driver is probed in U-Boot / Linux even if we
know there is no mSATA card, and similarly PCIe driver tries to link on
port 0 even if we know there is mSATA card, not a PCIe card.

Fixup device tree blob to disable SATA node if mSATA card is not
present, and to disable PCIe port 0 node if mSATA card is present.

Do this for U-Boot's DT blob before relocation and also for kernel DT
blob before booting.

This ensures that software does not try to use SATA or PCIe HW when
corresponding PHY is not configured.

Signed-off-by: Pali Rohár <pali@kernel.org>
[ refactored and fixed some issues ]
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>

board/CZ.NIC/turris_omnia/turris_omnia.c

@@ -490,6 +490,86 @@ void spl_board_init(void)
 	}
 }
 
+#if IS_ENABLED(CONFIG_OF_BOARD_FIXUP) || IS_ENABLED(CONFIG_OF_BOARD_SETUP)
+
+static void fixup_serdes_0_nodes(void *blob)
+{
+	bool mode_sata;
+	int node;
+
+	/*
+	 * Determine if SerDes 0 is configured to SATA mode.
+	 * We do this instead of calling omnia_detect_sata() to avoid another
+	 * call to the MCU. By this time the common PHYs are initialized (it is
+	 * done in SPL), so we can read this common PHY register.
+	 */
+	mode_sata = (readl(MVEBU_REGISTER(0x183fc)) & GENMASK(3, 0)) == 2;
+
+	/*
+	 * We're either adding status = "disabled" property, or changing
+	 * status = "okay" to status = "disabled". In both cases we'll need more
+	 * space. Increase the size a little.
+	 */
+	if (fdt_increase_size(blob, 32) < 0) {
+		printf("Cannot increase FDT size!\n");
+		return;
+	}
+
+	/* If mSATA card is not present, disable SATA DT node */
+	if (!mode_sata) {
+		fdt_for_each_node_by_compatible(node, blob, -1,
+						"marvell,armada-380-ahci") {
+			if (!fdtdec_get_is_enabled(blob, node))
+				continue;
+
+			if (fdt_status_disabled(blob, node) < 0)
+				printf("Cannot disable SATA DT node!\n");
+			else
+				debug("Disabled SATA DT node\n");
+
+			break;
+		}
+
+		return;
+	}
+
+	/* Otherwise disable PCIe port 0 DT node (MiniPCIe / mSATA port) */
+	fdt_for_each_node_by_compatible(node, blob, -1,
+					"marvell,armada-370-pcie") {
+		int port;
+
+		if (!fdtdec_get_is_enabled(blob, node))
+			continue;
+
+		fdt_for_each_subnode (port, blob, node) {
+			if (!fdtdec_get_is_enabled(blob, port))
+				continue;
+
+			if (fdtdec_get_int(blob, port, "marvell,pcie-port",
+					   -1) != 0)
+				continue;
+
+			if (fdt_status_disabled(blob, port) < 0)
+				printf("Cannot disable PCIe port 0 DT node!\n");
+			else
+				debug("Disabled PCIe port 0 DT node\n");
+
+			return;
+		}
+	}
+}
+
+#endif
+
+#if IS_ENABLED(CONFIG_OF_BOARD_FIXUP)
+int board_fix_fdt(void *blob)
+{
+	fixup_serdes_0_nodes(blob);
+
+	return 0;
+}
+#endif
+
 int board_init(void)
 {
 	/* address of boot parameters */
@@ -694,7 +774,7 @@ static bool fixup_mtd_partitions(void *blob, int offset, struct mtd_info *mtd)
 	return true;
 }
 
-int ft_board_setup(void *blob, struct bd_info *bd)
+static void fixup_spi_nor_partitions(void *blob)
 {
 	struct mtd_info *mtd;
 	int node;
@@ -711,12 +791,19 @@ int ft_board_setup(void *blob, struct bd_info *bd)
 		goto fail;
 
 	put_mtd_device(mtd);
-	return 0;
+	return;
 
 fail:
 	printf("Failed fixing SPI NOR partitions!\n");
 	if (!IS_ERR_OR_NULL(mtd))
 		put_mtd_device(mtd);
+}
+
+int ft_board_setup(void *blob, struct bd_info *bd)
+{
+	fixup_spi_nor_partitions(blob);
+	fixup_serdes_0_nodes(blob);
+
 	return 0;
 }
 #endif

configs/turris_omnia_defconfig

@@ -23,6 +23,7 @@ CONFIG_DEBUG_UART_BASE=0xd0012000
 CONFIG_DEBUG_UART_CLOCK=250000000
 CONFIG_DEBUG_UART=y
 CONFIG_AHCI=y
+CONFIG_OF_BOARD_FIXUP=y
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_SYS_LOAD_ADDR=0x800000
 CONFIG_FIT=y