ARM: OMAP2+: hwmod: Fix _wait_target_ready() for hwmods without sysc

commit 9a258afa upstream.

For hwmods without sysc, _init_mpu_rt_base(oh) won't be called and so
_find_mpu_rt_port(oh) will return NULL thus preventing ready state check
on those modules after the module is enabled.

This can potentially cause a bus access error if the module is accessed
before the module is ready.

Fix this by unconditionally calling _init_mpu_rt_base() during hwmod
_init(). Do ioremap only if we need SYSC access.

Eventhough _wait_target_ready() check doesn't really need MPU RT port but
just the PRCM registers, we still mandate that the hwmod must have an
MPU RT port if ready state check needs to be done. Else it would mean that
the module is not accessible by MPU so there is no point in waiting
for target to be ready.

e.g. this fixes the below DCAN bus access error on AM437x-gp-evm.

[   16.672978] ------------[ cut here ]------------
[   16.677885] WARNING: CPU: 0 PID: 1580 at drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x234/0x35c()
[   16.687946] 44000000.ocp:L3 Custom Error: MASTER M2 (64-bit) TARGET L4_PER_0 (Read): Data Access in User mode during Functional access
[   16.700654] Modules linked in: xhci_hcd btwilink ti_vpfe dwc3 videobuf2_core ov2659 bluetooth v4l2_common videodev ti_am335x_adc kfifo_buf industrialio c_can_platform videobuf2_dma_contig media snd_soc_tlv320aic3x pixcir_i2c_ts c_can dc
[   16.731144] CPU: 0 PID: 1580 Comm: rpc.statd Not tainted 3.14.26-02561-gf733aa036398 #180
[   16.739747] Backtrace:
[   16.742336] [<c0011108>] (dump_backtrace) from [<c00112a4>] (show_stack+0x18/0x1c)
[   16.750285]  r6:00000093 r5:00000009 r4:eab5b8a8 r3:00000000
[   16.756252] [<c001128c>] (show_stack) from [<c05a4418>] (dump_stack+0x20/0x28)
[   16.763870] [<c05a43f8>] (dump_stack) from [<c0037120>] (warn_slowpath_common+0x6c/0x8c)
[   16.772408] [<c00370b4>] (warn_slowpath_common) from [<c00371e4>] (warn_slowpath_fmt+0x38/0x40)
[   16.781550]  r8:c05d1f90 r7:c0730844 r6:c0730448 r5:80080003 r4:ed0cd210
[   16.788626] [<c00371b0>] (warn_slowpath_fmt) from [<c027fa94>] (l3_interrupt_handler+0x234/0x35c)
[   16.797968]  r3:ed0cd480 r2:c0730508
[   16.801747] [<c027f860>] (l3_interrupt_handler) from [<c0063758>] (handle_irq_event_percpu+0x54/0x1bc)
[   16.811533]  r10:ed005600 r9:c084855b r8:0000002a r7:00000000 r6:00000000 r5:0000002a
[   16.819780]  r4:ed0e6d80
[   16.822453] [<c0063704>] (handle_irq_event_percpu) from [<c00638f0>] (handle_irq_event+0x30/0x40)
[   16.831789]  r10:eb2b6938 r9:eb2b6960 r8:bf011420 r7:fa240100 r6:00000000 r5:0000002a
[   16.840052]  r4:ed005600
[   16.842744] [<c00638c0>] (handle_irq_event) from [<c00661d8>] (handle_fasteoi_irq+0x74/0x128)
[   16.851702]  r4:ed005600 r3:00000000
[   16.855479] [<c0066164>] (handle_fasteoi_irq) from [<c0063068>] (generic_handle_irq+0x28/0x38)
[   16.864523]  r4:0000002a r3:c0066164
[   16.868294] [<c0063040>] (generic_handle_irq) from [<c000ef60>] (handle_IRQ+0x38/0x8c)
[   16.876612]  r4:c081c640 r3:00000202
[   16.880380] [<c000ef28>] (handle_IRQ) from [<c00084f0>] (gic_handle_irq+0x30/0x5c)
[   16.888328]  r6:eab5ba38 r5:c0804460 r4:fa24010c r3:00000100
[   16.894303] [<c00084c0>] (gic_handle_irq) from [<c05a8d80>] (__irq_svc+0x40/0x50)
[   16.902193] Exception stack(0xeab5ba38 to 0xeab5ba80)
[   16.907499] ba20:                                                       00000000 00000006
[   16.916108] ba40: fa1d0000 fa1d0008 ed3d3000 eab5bab4 ed3d3460 c0842af4 bf011420 eb2b6960
[   16.924716] ba60: eb2b6938 eab5ba8c eab5ba90 eab5ba80 bf035220 bf07702c 600f0013 ffffffff
[   16.933317]  r7:eab5ba6c r6:ffffffff r5:600f0013 r4:bf07702c
[   16.939317] [<bf077000>] (c_can_plat_read_reg_aligned_to_16bit [c_can_platform]) from [<bf035220>] (c_can_get_berr_counter+0x38/0x64 [c_can])
[   16.952696] [<bf0351e8>] (c_can_get_berr_counter [c_can]) from [<bf010294>] (can_fill_info+0x124/0x15c [can_dev])
[   16.963480]  r5:ec8c9740 r4:ed3d3000
[   16.967253] [<bf010170>] (can_fill_info [can_dev]) from [<c0502fa8>] (rtnl_fill_ifinfo+0x58c/0x8fc)
[   16.976749]  r6:ec8c9740 r5:ed3d3000 r4:eb2b6780
[   16.981613] [<c0502a1c>] (rtnl_fill_ifinfo) from [<c0503408>] (rtnl_dump_ifinfo+0xf0/0x1dc)
[   16.990401]  r10:ec8c9740 r9:00000000 r8:00000000 r7:00000000 r6:ebd4d1b4 r5:ed3d3000
[   16.998671]  r4:00000000
[   17.001342] [<c0503318>] (rtnl_dump_ifinfo) from [<c050e6e4>] (netlink_dump+0xa8/0x1e0)
[   17.009772]  r10:00000000 r9:00000000 r8:c0503318 r7:ebf3e6c0 r6:ebd4d1b4 r5:ec8c9740
[   17.018050]  r4:ebd4d000
[   17.020714] [<c050e63c>] (netlink_dump) from [<c050ec10>] (__netlink_dump_start+0x104/0x154)
[   17.029591]  r6:eab5bd34 r5:ec8c9980 r4:ebd4d000
[   17.034454] [<c050eb0c>] (__netlink_dump_start) from [<c0505604>] (rtnetlink_rcv_msg+0x110/0x1f4)
[   17.043778]  r7:00000000 r6:ec8c9980 r5:00000f40 r4:ebf3e6c0
[   17.049743] [<c05054f4>] (rtnetlink_rcv_msg) from [<c05108e8>] (netlink_rcv_skb+0xb4/0xc8)
[   17.058449]  r8:eab5bdac r7:ec8c9980 r6:c05054f4 r5:ec8c9980 r4:ebf3e6c0
[   17.065534] [<c0510834>] (netlink_rcv_skb) from [<c0504134>] (rtnetlink_rcv+0x24/0x2c)
[   17.073854]  r6:ebd4d000 r5:00000014 r4:ec8c9980 r3:c0504110
[   17.079846] [<c0504110>] (rtnetlink_rcv) from [<c05102ac>] (netlink_unicast+0x180/0x1ec)
[   17.088363]  r4:ed0c6800 r3:c0504110
[   17.092113] [<c051012c>] (netlink_unicast) from [<c0510670>] (netlink_sendmsg+0x2ac/0x380)
[   17.100813]  r10:00000000 r8:00000008 r7:ec8c9980 r6:ebd4d000 r5:eab5be70 r4:eab5bee4
[   17.109083] [<c05103c4>] (netlink_sendmsg) from [<c04dfdb4>] (sock_sendmsg+0x90/0xb0)
[   17.117305]  r10:00000000 r9:eab5a000 r8:becdda3c r7:0000000c r6:ea978400 r5:eab5be70
[   17.125563]  r4:c05103c4
[   17.128225] [<c04dfd24>] (sock_sendmsg) from [<c04e1c28>] (SyS_sendto+0xb8/0xdc)
[   17.136001]  r6:becdda5c r5:00000014 r4:ecd37040
[   17.140876] [<c04e1b70>] (SyS_sendto) from [<c000e680>] (ret_fast_syscall+0x0/0x30)
[   17.148923]  r10:00000000 r8:c000e804 r7:00000122 r6:becdda5c r5:0000000c r4:becdda5c
[   17.157169] ---[ end trace 2b71e15b38f58bad ]---

Fixes: 6423d6df ("ARM: OMAP2+: hwmod: check for module address space during init")
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

arch/arm/mach-omap2/omap_hwmod.c

@@ -2368,6 +2368,9 @@ static int of_dev_hwmod_lookup(struct device_node *np,
  * registers.  This address is needed early so the OCP registers that
  * are part of the device's address space can be ioremapped properly.
  *
+ * If SYSC access is not needed, the registers will not be remapped
+ * and non-availability of MPU access is not treated as an error.
+ *
  * Returns 0 on success, -EINVAL if an invalid hwmod is passed, and
  * -ENXIO on absent or invalid register target address space.
  */
@@ -2382,6 +2385,11 @@ static int __init _init_mpu_rt_base(struct omap_hwmod *oh, void *data,
 
 	_save_mpu_port_index(oh);
 
+	/* if we don't need sysc access we don't need to ioremap */
+	if (!oh->class->sysc)
+		return 0;
+
+	/* we can't continue without MPU PORT if we need sysc access */
 	if (oh->_int_flags & _HWMOD_NO_MPU_PORT)
 		return -ENXIO;
 
@@ -2391,8 +2399,10 @@ static int __init _init_mpu_rt_base(struct omap_hwmod *oh, void *data,
 			 oh->name);
 
 		/* Extract the IO space from device tree blob */
-		if (!np)
+		if (!np) {
+			pr_err("omap_hwmod: %s: no dt node\n", oh->name);
 			return -ENXIO;
+		}
 
 		va_start = of_iomap(np, index + oh->mpu_rt_idx);
 	} else {
@@ -2451,14 +2461,12 @@ static int __init _init(struct omap_hwmod *oh, void *data)
 				oh->name, np->name);
 	}
 
-	if (oh->class->sysc) {
 	r = _init_mpu_rt_base(oh, NULL, index, np);
 	if (r < 0) {
 		WARN(1, "omap_hwmod: %s: doesn't have mpu register target base\n",
 		     oh->name);
 		return 0;
 	}
-	}
 
 	r = _init_clocks(oh, NULL);
 	if (r < 0) {