memory: tegra: Read client ID on GART page fault

With the device tree binding changes, now Memory Controller has access to
GART registers. Hence it is now possible to read client ID on GART page
fault to get information about what memory client causes the fault.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/memory/tegra/mc.c

@@ -38,6 +38,7 @@
 
 #define MC_ERR_ADR 0x0c
 
+#define MC_GART_ERROR_REQ		0x30
 #define MC_DECERR_EMEM_OTHERS_STATUS	0x58
 #define MC_SECURITY_VIOLATION_STATUS	0x74
 
@@ -575,8 +576,15 @@ static __maybe_unused irqreturn_t tegra20_mc_irq(int irq, void *data)
 			break;
 
 		case MC_INT_INVALID_GART_PAGE:
-			dev_err_ratelimited(mc->dev, "%s\n", error);
-			continue;
+			reg = MC_GART_ERROR_REQ;
+			value = mc_readl(mc, reg);
+
+			id = (value >> 1) & mc->soc->client_id_mask;
+			desc = error_names[2];
+
+			if (value & BIT(0))
+				direction = "write";
+			break;
 
 		case MC_INT_SECURITY_VIOLATION:
 			reg = MC_SECURITY_VIOLATION_STATUS;