diff options
Diffstat (limited to 'arch/arm/mach-zynq/slcr.c')
-rw-r--r-- | arch/arm/mach-zynq/slcr.c | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/arch/arm/mach-zynq/slcr.c b/arch/arm/mach-zynq/slcr.c new file mode 100644 index 00000000000..c70969b9c25 --- /dev/null +++ b/arch/arm/mach-zynq/slcr.c @@ -0,0 +1,125 @@ +/* + * Xilinx SLCR driver + * + * Copyright (c) 2011-2013 Xilinx Inc. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + * You should have received a copy of the GNU General Public + * License along with this program; if not, write to the Free + * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA + * 02139, USA. + */ + +#include <linux/export.h> +#include <linux/io.h> +#include <linux/fs.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/uaccess.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <linux/clk/zynq.h> +#include "common.h" + +#define SLCR_UNLOCK_MAGIC 0xDF0D +#define SLCR_UNLOCK 0x8 /* SCLR unlock register */ + +#define SLCR_PS_RST_CTRL_OFFSET 0x200 /* PS Software Reset Control */ + +#define SLCR_A9_CPU_CLKSTOP 0x10 +#define SLCR_A9_CPU_RST 0x1 + +#define SLCR_A9_CPU_RST_CTRL 0x244 /* CPU Software Reset Control */ +#define SLCR_REBOOT_STATUS 0x258 /* PS Reboot Status */ + +void __iomem *zynq_slcr_base; + +/** + * zynq_slcr_system_reset - Reset the entire system. + */ +void zynq_slcr_system_reset(void) +{ + u32 reboot; + + /* + * Unlock the SLCR then reset the system. + * Note that this seems to require raw i/o + * functions or there's a lockup? + */ + writel(SLCR_UNLOCK_MAGIC, zynq_slcr_base + SLCR_UNLOCK); + + /* + * Clear 0x0F000000 bits of reboot status register to workaround + * the FSBL not loading the bitstream after soft-reboot + * This is a temporary solution until we know more. + */ + reboot = readl(zynq_slcr_base + SLCR_REBOOT_STATUS); + writel(reboot & 0xF0FFFFFF, zynq_slcr_base + SLCR_REBOOT_STATUS); + writel(1, zynq_slcr_base + SLCR_PS_RST_CTRL_OFFSET); +} + +/** + * zynq_slcr_cpu_start - Start cpu + * @cpu: cpu number + */ +void zynq_slcr_cpu_start(int cpu) +{ + /* enable CPUn */ + writel(SLCR_A9_CPU_CLKSTOP << cpu, + zynq_slcr_base + SLCR_A9_CPU_RST_CTRL); + /* enable CLK for CPUn */ + writel(0x0 << cpu, zynq_slcr_base + SLCR_A9_CPU_RST_CTRL); +} + +/** + * zynq_slcr_cpu_stop - Stop cpu + * @cpu: cpu number + */ +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); +} + +/** + * zynq_slcr_init + * Returns 0 on success, negative errno otherwise. + * + * Called early during boot from platform code to remap SLCR area. + */ +int __init zynq_slcr_init(void) +{ + struct device_node *np; + + np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-slcr"); + if (!np) { + pr_err("%s: no slcr node found\n", __func__); + BUG(); + } + + zynq_slcr_base = of_iomap(np, 0); + if (!zynq_slcr_base) { + pr_err("%s: Unable to map I/O memory\n", __func__); + BUG(); + } + + /* unlock the SLCR so that registers can be changed */ + writel(SLCR_UNLOCK_MAGIC, zynq_slcr_base + SLCR_UNLOCK); + + pr_info("%s mapped to %p\n", np->name, zynq_slcr_base); + + xilinx_zynq_clocks_init(zynq_slcr_base); + + of_node_put(np); + + return 0; +} |