arm/mach-npcm/platsmp.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 // Copyright (c) 2018 Nuvoton Technology corporation.
0003 // Copyright 2018 Google, Inc.
0004
0005 #define pr_fmt(fmt) "nuvoton,npcm7xx-smp: " fmt
0006
0007 #include <linux/delay.h>
0008 #include <linux/device.h>
0009 #include <linux/smp.h>
0010 #include <linux/io.h>
0011 #include <linux/of.h>
0012 #include <linux/of_device.h>
0013 #include <linux/of_platform.h>
0014 #include <linux/of_address.h>
0015 #include <asm/cacheflush.h>
0016 #include <asm/smp.h>
0017 #include <asm/smp_plat.h>
0018 #include <asm/smp_scu.h>
0019
0020 #define NPCM7XX_SCRPAD_REG 0x13c
0021
0022 extern void npcm7xx_secondary_startup(void);
0023
0024 static int npcm7xx_smp_boot_secondary(unsigned int cpu,
0025                       struct task_struct *idle)
0026 {
0027     struct device_node *gcr_np;
0028     void __iomem *gcr_base;
0029     int ret = 0;
0030
0031     gcr_np = of_find_compatible_node(NULL, NULL, "nuvoton,npcm750-gcr");
0032     if (!gcr_np) {
0033         pr_err("no gcr device node\n");
0034         ret = -ENODEV;
0035         goto out;
0036     }
0037     gcr_base = of_iomap(gcr_np, 0);
0038     if (!gcr_base) {
0039         pr_err("could not iomap gcr");
0040         ret = -ENOMEM;
0041         goto out;
0042     }
0043
0044     /* give boot ROM kernel start address. */
0045     iowrite32(__pa_symbol(npcm7xx_secondary_startup), gcr_base +
0046           NPCM7XX_SCRPAD_REG);
0047     /* make sure the previous write is seen by all observers. */
0048     dsb_sev();
0049
0050     iounmap(gcr_base);
0051 out:
0052     return ret;
0053 }
0054
0055 static void __init npcm7xx_smp_prepare_cpus(unsigned int max_cpus)
0056 {
0057     struct device_node *scu_np;
0058     void __iomem *scu_base;
0059
0060     scu_np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
0061     if (!scu_np) {
0062         pr_err("no scu device node\n");
0063         return;
0064     }
0065     scu_base = of_iomap(scu_np, 0);
0066     if (!scu_base) {
0067         pr_err("could not iomap scu");
0068         return;
0069     }
0070
0071     scu_enable(scu_base);
0072
0073     iounmap(scu_base);
0074 }
0075
0076 static struct smp_operations npcm7xx_smp_ops __initdata = {
0077     .smp_prepare_cpus = npcm7xx_smp_prepare_cpus,
0078     .smp_boot_secondary = npcm7xx_smp_boot_secondary,
0079 };
0080
0081 CPU_METHOD_OF_DECLARE(npcm7xx_smp, "nuvoton,npcm750-smp", &npcm7xx_smp_ops);