clk: samsung: exynos5420: Keep top G3D clocks enabled

All top clocks on G3D path has to be enabled all the time to allow proper
G3D power domain operation. This is achieved by adding CRITICAL flag to
"mout_sw_aclk_g3d" clock, what keeps this clock and all its parents
enabled.

This fixes following imprecise abort issue observed on Odroid XU3/XU4
after enabling Panfrost driver by commit 1a5a85c "ARM: dts: exynos:
Add Mali/GPU node on Exynos5420 and enable it on Odroid XU3/4"):

panfrost 11800000.gpu: clock rate = 400000000
panfrost 11800000.gpu: failed to get regulator: -517
panfrost 11800000.gpu: regulator init failed -517
Power domain G3D disable failed
...
panfrost 11800000.gpu: clock rate = 400000000
8<--- cut here ---
Unhandled fault: imprecise external abort (0x1406) at 0x00000000
pgd = (ptrval)
[00000000] *pgd=00000000
Internal error: : 1406 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 7 PID: 53 Comm: kworker/7:1 Not tainted 5.4.0-rc8-next-20191119-00032-g56f1001191a6 #6923
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
Workqueue: events deferred_probe_work_func
PC is at panfrost_gpu_soft_reset+0x94/0x110
LR is at ___might_sleep+0x128/0x2dc
...
[<c05c231c>] (panfrost_gpu_soft_reset) from [<c05c2704>] (panfrost_gpu_init+0x10/0x67c)
[<c05c2704>] (panfrost_gpu_init) from [<c05c15d0>] (panfrost_device_init+0x158/0x2cc)
[<c05c15d0>] (panfrost_device_init) from [<c05c0cb0>] (panfrost_probe+0x80/0x178)
[<c05c0cb0>] (panfrost_probe) from [<c05cfaa0>] (platform_drv_probe+0x48/0x9c)
[<c05cfaa0>] (platform_drv_probe) from [<c05cd20c>] (really_probe+0x1c4/0x474)
[<c05cd20c>] (really_probe) from [<c05cd694>] (driver_probe_device+0x78/0x1bc)
[<c05cd694>] (driver_probe_device) from [<c05cb374>] (bus_for_each_drv+0x74/0xb8)
[<c05cb374>] (bus_for_each_drv) from [<c05ccfa8>] (__device_attach+0xd4/0x16c)
[<c05ccfa8>] (__device_attach) from [<c05cc110>] (bus_probe_device+0x88/0x90)
[<c05cc110>] (bus_probe_device) from [<c05cc634>] (deferred_probe_work_func+0x4c/0xd0)
[<c05cc634>] (deferred_probe_work_func) from [<c0149df0>] (process_one_work+0x300/0x864)
[<c0149df0>] (process_one_work) from [<c014a3ac>] (worker_thread+0x58/0x5a0)
[<c014a3ac>] (worker_thread) from [<c0151174>] (kthread+0x12c/0x160)
[<c0151174>] (kthread) from [<c01010b4>] (ret_from_fork+0x14/0x20)
Exception stack(0xee03dfb0 to 0xee03dff8)
...
Code: e594300c e5933020 e3130c01 1a00000f (ebefff50).
---[ end trace badde2b74a65a540 ]---

In the above case, the Panfrost driver disables G3D clocks after failure
of getting the needed regulator and return with -EPROVE_DEFER code. This
causes G3D power domain disable failure and then, during second probe
an imprecise abort is triggered due to undefined power domain state.

Fixes: 45f10da ("clk: samsung: exynos5420: Add SET_RATE_PARENT flag to clocks on G3D path")
Fixes: c9f7567 ("clk: samsung: exynos542x: Move G3D subsystem clocks to its sub-CMU")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>

Signed-off-by: Marian Mihailescu <mihailescu2m@gmail.com>

drivers/clk/samsung/clk-exynos5420.c

@@ -712,7 +712,7 @@ static const struct samsung_mux_clock exynos5x_mux_clks[] __initconst = {
 	MUX(0, "mout_sw_aclk266_g2d", mout_sw_aclk266_g2d_p,
 			SRC_TOP12, 12, 1),
 	MUX_F(0, "mout_sw_aclk_g3d", mout_sw_aclk_g3d_p, SRC_TOP12, 16, 1,
-	      CLK_SET_RATE_PARENT, 0),
+	      CLK_IS_CRITICAL | CLK_SET_RATE_PARENT, 0),
 	MUX(0, "mout_sw_aclk300_jpeg", mout_sw_aclk300_jpeg_p,
 			SRC_TOP12, 20, 1),
 	MUX(CLK_MOUT_SW_ACLK300, "mout_sw_aclk300_disp1",