From: Soren Brinkmann Date: Wed, 17 Jul 2013 17:10:15 +0000 (-0700) Subject: arm: zynq: slcr: Use read-modify-write for register writes X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3db9e86029349c2c84928b5a0f7c7cf324243b4f;p=linux-beck.git arm: zynq: slcr: Use read-modify-write for register writes zynq_slcr_cpu_start/stop() ignored the current register state when writing to a register. Fixing this by implementing proper read-modify-write. Signed-off-by: Soren Brinkmann Signed-off-by: Michal Simek --- diff --git a/arch/arm/mach-zynq/slcr.c b/arch/arm/mach-zynq/slcr.c index 44a4ab62e9a8..1836d5a34606 100644 --- a/arch/arm/mach-zynq/slcr.c +++ b/arch/arm/mach-zynq/slcr.c @@ -61,11 +61,11 @@ void zynq_slcr_system_reset(void) */ void zynq_slcr_cpu_start(int cpu) { - /* enable CPUn */ - writel(SLCR_A9_CPU_CLKSTOP << cpu, - zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); - /* enable CLK for CPUn */ - writel(0x0 << cpu, zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); + u32 reg = readl(zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); + reg &= ~(SLCR_A9_CPU_RST << cpu); + writel(reg, zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); + reg &= ~(SLCR_A9_CPU_CLKSTOP << cpu); + writel(reg, zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); } /** @@ -74,9 +74,9 @@ void zynq_slcr_cpu_start(int cpu) */ void zynq_slcr_cpu_stop(int cpu) { - /* stop CLK and reset CPUn */ - writel((SLCR_A9_CPU_CLKSTOP | SLCR_A9_CPU_RST) << cpu, - zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); + u32 reg = readl(zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); + reg |= (SLCR_A9_CPU_CLKSTOP | SLCR_A9_CPU_RST) << cpu; + writel(reg, zynq_slcr_base + SLCR_A9_CPU_RST_CTRL_OFFSET); } /**