[PATCH v1 3/3] arm: mach-k3: am62: Fixup CPU core counts in fdt

[Francesco Dolcini]

From: Emanuele Ghidoli <emanuele.ghidoli at toradex.com>

AM62x SoC is available in multiple variant with a different
amount of CPU cores (Cortex-A) available, AM62x1, AM62x2, AM62x4
have respectively 1, 2 or 4 cores.

Update the FDT with the actual core count as read from the SoC registers,
with that change is possible to have a single dts/dtb file handling
the different variant at runtime.

A similar approach is implemented for example on i.MX8 and STM32MP1 SoC.

Signed-off-by: Emanuele Ghidoli <emanuele.ghidoli at toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini at toradex.com>
---
 arch/arm/mach-k3/common.c | 48 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
index f86ccaedc94f..5ee1851e3aaa 100644
--- a/arch/arm/mach-k3/common.c
+++ b/arch/arm/mach-k3/common.c
@@ -431,10 +431,58 @@ int fdt_fixup_msmc_ram(void *blob, char *parent_path, char *node_name)
 }
 
 #if defined(CONFIG_OF_SYSTEM_SETUP)
+static int fdt_del_node_path(void *blob, const char *path)
+{
+	int rc;
+	int nodeoff;
+
+	nodeoff = fdt_path_offset(blob, path);
+	if (nodeoff < 0)
+		return 0; /* Not found, skip it */
+
+	rc = fdt_del_node(blob, nodeoff);
+	if (rc < 0)
+		printf("Unable to delete node %s, err=%s\n", path, fdt_strerror(rc));
+	else
+		debug("Deleted node %s\n", path);
+	return rc;
+}
+
+static void fdt_fixup_cores_nodes_am625(void *blob, int core_nr)
+{
+	char node_path[32];
+
+	if (core_nr < 1)
+		return;
+
+	for (; core_nr < 4; core_nr++) {
+		snprintf(node_path, sizeof(node_path), "/cpus/cpu@%d", core_nr);
+		fdt_del_node_path(blob, node_path);
+		snprintf(node_path, sizeof(node_path), "/cpus/cpu-map/cluster0/core%d", core_nr);
+		fdt_del_node_path(blob, node_path);
+		snprintf(node_path, sizeof(node_path), "/bus at f0000/watchdog at e0%d0000", core_nr);
+		fdt_del_node_path(blob, node_path);
+	}
+}
+
+static int k3_get_core_nr(void)
+{
+#if defined(CONFIG_SOC_K3_AM625)
+	u32 full_devid = readl(CTRLMMR_WKUP_JTAG_DEVICE_ID);
+
+	return (full_devid & JTAG_DEV_CORE_NR_MASK) >> JTAG_DEV_CORE_NR_SHIFT;
+#else
+	return -1;
+#endif
+}
+
 int ft_system_setup(void *blob, struct bd_info *bd)
 {
 	int ret = 0;
 
+	if (IS_ENABLED(CONFIG_SOC_K3_AM625))
+		fdt_fixup_cores_nodes_am625(blob, k3_get_core_nr());
+
 	if (IS_ENABLED(CONFIG_SOC_K3_J721S2) ||
 	    IS_ENABLED(CONFIG_SOC_K3_AM654) ||
 	    IS_ENABLED(CONFIG_SOC_K3_J721E)) {
-- 
2.25.1