bus: omap_l3_noc: fix masterid detection

As per Documentation (OMAP4+), then masterid is infact encoded as
follows:
"L3_TARG_STDERRLOG_MSTADDR[7:0] STDERRLOG_MSTADDR stores the NTTP
master address. The master address is the concatenation of Prefix &
Initiator ConnID. It is defined on 8 bits. The 6 MSBs are used to
distinguish the different initiators."

So, when we matchup currently with the master ID list, we never get a
proper match other than when MPU is the master (thanks to 0).

Now, on other platforms such as AM437x, this tends to be bits[5:0].

Fix this by using the relevant 6MSBits to identify the master ID for
standard and custom errors.

Reported-by: Darren Etheridge <detheridge@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Tested-by: Darren Etheridge <detheridge@ti.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>

drivers/bus/omap_l3_noc.c

@@ -127,7 +127,11 @@ static irqreturn_t l3_interrupt_handler(int irq, void *_l3)
 					  L3_TARG_STDERRLOG_MSTADDR;
 
 			std_err_main = readl_relaxed(l3_targ_stderr);
-			masterid = readl_relaxed(l3_targ_mstaddr);
+
+			/* STDERRLOG_MSTADDR Stores the NTTP master address. */
+			masterid = (readl_relaxed(l3_targ_mstaddr) &
+				    l3->mst_addr_mask) >>
+					__ffs(l3->mst_addr_mask);
 
 			switch (std_err_main & CUSTOM_ERROR) {
 			case STANDARD_ERROR:

drivers/bus/omap_l3_noc.h

@@ -84,6 +84,7 @@ struct l3_flagmux_data {
  * @l3_masters:	array pointing to master data containing name and register
  *		offset for the master.
  * @num_master: number of masters
+ * @mst_addr_mask: Mask representing MSTADDR information of NTTP packet
  * @debug_irq:	irq number of the debug interrupt (populated runtime)
  * @app_irq:	irq number of the application interrupt (populated runtime)
  */
@@ -96,6 +97,7 @@ struct omap_l3 {
 
 	struct l3_masters_data *l3_masters;
 	int num_masters;
+	u32 mst_addr_mask;
 
 	int debug_irq;
 	int app_irq;
@@ -200,6 +202,8 @@ static const struct omap_l3 omap_l3_data = {
 	.num_modules = ARRAY_SIZE(omap_l3_flagmux),
 	.l3_masters = omap_l3_masters,
 	.num_masters = ARRAY_SIZE(omap_l3_masters),
+	/* The 6 MSBs of register field used to distinguish initiator */
+	.mst_addr_mask = 0xFC,
 };
 
 #endif	/* __OMAP_L3_NOC_H */