soc/tegra: cbb: Fix cross-fabric target timeout lookup

[ Upstream commit a5f51b0 ]

When a fabric receives an error interrupt, the error may have
occurred on a different fabric. The target timeout lookup was using
the wrong base address (cbb->regs) with offsets from a different
fabric's target map, causing a kernel page fault.

  Unable to handle kernel paging request at virtual address ffff80000954cc00
  pc : tegra234_cbb_get_tmo_slv+0xc/0x28
  Call trace:
   tegra234_cbb_get_tmo_slv+0xc/0x28
   print_err_notifier+0x6c0/0x7d0
   tegra234_cbb_isr+0xe4/0x1b4

Add tegra234_cbb_get_fabric() to look up the correct fabric device
using fab_id, and use its base address for accessing target timeout
registers.

Fixes: 25de5c8 ("soc/tegra: cbb: Improve handling for per SoC fabric data")
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Sumit Gupta

drivers/soc/tegra/cbb/tegra234-cbb.c

@@ -313,12 +313,37 @@ static void tegra234_cbb_lookup_apbslv(struct seq_file *file, const char *target
 	}
 }
 
+static struct tegra234_cbb *tegra234_cbb_get_fabric(u8 fab_id)
+{
+	struct tegra_cbb *entry;
+
+	list_for_each_entry(entry, &cbb_list, node) {
+		struct tegra234_cbb *priv = to_tegra234_cbb(entry);
+
+		if (priv->fabric->fab_id == fab_id)
+			return priv;
+	}
+
+	return NULL;
+}
+
 static void tegra234_sw_lookup_target_timeout(struct seq_file *file, struct tegra234_cbb *cbb,
 					      u8 target_id, u8 fab_id)
 {
 	const struct tegra234_target_lookup *map = cbb->fabric->fab_list[fab_id].target_map;
+	struct tegra234_cbb *target_cbb = NULL;
 	void __iomem *addr;
 
+	if (fab_id == cbb->fabric->fab_id)
+		target_cbb = cbb;
+	else
+		target_cbb = tegra234_cbb_get_fabric(fab_id);
+
+	if (!target_cbb) {
+		dev_err(cbb->base.dev, "could not find fabric for fab_id:%d\n", fab_id);
+		return;
+	}
+
 	if (target_id >= cbb->fabric->fab_list[fab_id].max_targets) {
 		tegra_cbb_print_err(file, "\t  Invalid target_id:%d\n", target_id);
 		return;
@@ -341,7 +366,7 @@ static void tegra234_sw_lookup_target_timeout(struct seq_file *file, struct tegr
 	 *	e) Goto step-a till all bits are set.
 	 */
 
-	addr = cbb->regs + map[target_id].offset;
+	addr = target_cbb->regs + map[target_id].offset;
 
 	if (strstr(map[target_id].name, "AXI2APB")) {
 		addr += APB_BLOCK_TMO_STATUS_0;