From e984a1791ac6a7c944911207e8a9c344763f0003 Mon Sep 17 00:00:00 2001 From: Tomeu Vizoso Date: Wed, 5 Aug 2015 14:24:15 +0200 Subject: [PATCH] memory: omap-gpmc: Don't try to save uninitialized GPMC context If for some reason the GPMC device hasn't been probed yet, gpmc_base is going to be NULL. Because there's no context yet to be saved, just turn these functions into no-ops until that device gets probed. Unable to handle kernel NULL pointer dereference at virtual address 00000010 pgd = c0204000 [00000010] *pgd=00000000 Internal error: Oops: 5 [#1] SMP ARM Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.2.0-rc5-next-20150804-05947-g23f38fe8eda9 #1 Hardware name: Generic OMAP3-GP (Flattened Device Tree) task: c0e623e8 ti: c0e5c000 task.ti: c0e5c000 PC is at omap3_gpmc_save_context+0x8/0xc4 LR is at omap_sram_idle+0x154/0x23c pc : [] lr : [] psr: 60000193 sp : c0e5df40 ip : c0f92a80 fp : c0999eb0 r10: c0e57364 r9 : c0e66f14 r8 : 00000003 r7 : 00000000 r6 : 00000003 r5 : 00000000 r4 : c0f5f174 r3 : c0fa4fe8 r2 : 00000000 r1 : 00000000 r0 : fa200280 Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c5387d Table: 80204019 DAC: 00000015 Process swapper/0 (pid: 0, stack limit = 0xc0e5c220) Stack: (0xc0e5df40 to 0xc0e5e000) df40: 00000000 c0e66ef8 c0f5f1a4 00000000 00000003 c02333a4 c3813822 00000000 df60: 00000000 c0e5a5c8 cfb8a5d0 c07f0c44 0e4f1d7e 00000000 00000000 00000000 df80: c3813822 00000000 cfb8a5d0 c0e5e4e4 cfb8a5d0 c0e66f14 c0e5a5c8 c0e5e54c dfa0: c0e5e544 c0e57364 c0999eb0 c0277758 000000fa c0f5d000 00000000 c0d61c18 dfc0: ffffffff ffffffff 00000000 c0d61674 00000000 c0df7a48 00000000 c0f5d5d4 dfe0: c0e5e4c0 c0df7a44 c0e634f8 80204059 00000000 8020807c 00000000 00000000 [] (omap3_gpmc_save_context) from [] (omap_sram_idle+0x154/0x23c) [] (omap_sram_idle) from [] (omap3_enter_idle_bm+0xec/0x1a8) [] (omap3_enter_idle_bm) from [] (cpuidle_enter_state+0xbc/0x284) [] (cpuidle_enter_state) from [] (cpu_startup_entry+0x174/0x24c) [] (cpu_startup_entry) from [] (start_kernel+0x358/0x3c0) [] (start_kernel) from [<8020807c>] (0x8020807c) Code: c0ccace8 c0ccacc0 e59f30b4 e5932000 (e5921010) Signed-off-by: Tomeu Vizoso Suggested-by: Javier Martinez Canillas Reviewed-by: Javier Martinez Canillas Acked-by: Roger Quadros [tony@atomide.com: updated description as suggested by Javier] Signed-off-by: Tony Lindgren --- drivers/memory/omap-gpmc.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/memory/omap-gpmc.c b/drivers/memory/omap-gpmc.c index 3a27a84ad3ec..9426276dbe14 100644 --- a/drivers/memory/omap-gpmc.c +++ b/drivers/memory/omap-gpmc.c @@ -2245,6 +2245,9 @@ void omap3_gpmc_save_context(void) { int i; + if (!gpmc_base) + return; + gpmc_context.sysconfig = gpmc_read_reg(GPMC_SYSCONFIG); gpmc_context.irqenable = gpmc_read_reg(GPMC_IRQENABLE); gpmc_context.timeout_ctrl = gpmc_read_reg(GPMC_TIMEOUT_CONTROL); @@ -2277,6 +2280,9 @@ void omap3_gpmc_restore_context(void) { int i; + if (!gpmc_base) + return; + gpmc_write_reg(GPMC_SYSCONFIG, gpmc_context.sysconfig); gpmc_write_reg(GPMC_IRQENABLE, gpmc_context.irqenable); gpmc_write_reg(GPMC_TIMEOUT_CONTROL, gpmc_context.timeout_ctrl);