From e34084fb9a023d1dd008c989523af5a037f1d692 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 17 Mar 2015 17:20:52 +0100 Subject: [PATCH] clk: renesas: mstp: Make INTC-SYS a critical clock INTC-SYS is the module clock for the GIC. Accessing the GIC while it is disabled causes: Unhandled fault: asynchronous external abort (0x1211) at 0x00000000 Currently, the GIC-400 driver cannot enable its module clock for several reasons: - It does not use a platform device, so Runtime PM is not an option, - gic_of_init() runs before any clocks are registered, so it cannot enable the clock explicitly, - gic_of_init() cannot return -EPROBE_DEFER, as IRQCHIP_DECLARE() doesn't support deferred probing. Hence we have to keep on relying on the boot loader for enabling the module clock. To prevent the module clock from being disabled when the CCF core thinks it is unused, and thus causing a system lock-up, add a check to the MSTP clock driver and enable CLK_IS_CRITICAL. This will make sure the module clock is never disabled. This is a hard dependency for describing the INTC-SYS clock in DT on R-Mobile APE6 and R-Car Gen2. Signed-off-by: Geert Uytterhoeven Acked-by: Stephen Boyd --- drivers/clk/renesas/clk-mstp.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/clk/renesas/clk-mstp.c b/drivers/clk/renesas/clk-mstp.c index 9375777..c0319b8 100644 --- a/drivers/clk/renesas/clk-mstp.c +++ b/drivers/clk/renesas/clk-mstp.c @@ -144,6 +144,11 @@ cpg_mstp_clock_register(const char *name, const char *parent_name, init.name = name; init.ops = &cpg_mstp_clock_ops; init.flags = CLK_IS_BASIC | CLK_SET_RATE_PARENT; + /* INTC-SYS is the module clock of the GIC, and must not be disabled */ + if (!strcmp(name, "intc-sys")) { + pr_debug("MSTP %s setting CLK_IS_CRITICAL\n", name); + init.flags |= CLK_IS_CRITICAL; + } init.parent_names = &parent_name; init.num_parents = 1; -- 2.7.4