diff options
Diffstat (limited to 'drivers/soc/renesas/r9a06g032-smp.c')
| -rw-r--r-- | drivers/soc/renesas/r9a06g032-smp.c | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/drivers/soc/renesas/r9a06g032-smp.c b/drivers/soc/renesas/r9a06g032-smp.c new file mode 100644 index 000000000000..a1926e8d73f2 --- /dev/null +++ b/drivers/soc/renesas/r9a06g032-smp.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * R9A06G032 Second CA7 enabler. + * + * Copyright (C) 2018 Renesas Electronics Europe Limited + * + * Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com> + * Derived from actions,s500-smp + */ + +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/smp.h> + +/* + * The second CPU is parked in ROM at boot time. It requires waking it after + * writing an address into the BOOTADDR register of sysctrl. + * + * So the default value of the "cpu-release-addr" corresponds to BOOTADDR... + * + * *However* the BOOTADDR register is not available when the kernel + * starts in NONSEC mode. + * + * So for NONSEC mode, the bootloader re-parks the second CPU into a pen + * in SRAM, and changes the "cpu-release-addr" of linux's DT to a SRAM address, + * which is not restricted. + */ + +static void __iomem *cpu_bootaddr; + +static DEFINE_SPINLOCK(cpu_lock); + +static int +r9a06g032_smp_boot_secondary(unsigned int cpu, + struct task_struct *idle) +{ + if (!cpu_bootaddr) + return -ENODEV; + + spin_lock(&cpu_lock); + + writel(__pa_symbol(secondary_startup), cpu_bootaddr); + arch_send_wakeup_ipi_mask(cpumask_of(cpu)); + + spin_unlock(&cpu_lock); + + return 0; +} + +static void __init r9a06g032_smp_prepare_cpus(unsigned int max_cpus) +{ + struct device_node *dn; + int ret = -EINVAL, dns; + u32 bootaddr; + + dn = of_get_cpu_node(1, NULL); + if (!dn) { + pr_err("CPU#1: missing device tree node\n"); + return; + } + /* + * Determine the address from which the CPU is polling. + * The bootloader *does* change this property. + * Note: The property can be either 64 or 32 bits, so handle both cases + */ + if (of_find_property(dn, "cpu-release-addr", &dns)) { + if (dns == sizeof(u64)) { + u64 temp; + + ret = of_property_read_u64(dn, + "cpu-release-addr", &temp); + bootaddr = temp; + } else { + ret = of_property_read_u32(dn, + "cpu-release-addr", + &bootaddr); + } + } + of_node_put(dn); + if (ret) { + pr_err("CPU#1: invalid cpu-release-addr property\n"); + return; + } + pr_info("CPU#1: cpu-release-addr %08x\n", bootaddr); + + cpu_bootaddr = ioremap(bootaddr, sizeof(bootaddr)); +} + +static const struct smp_operations r9a06g032_smp_ops __initconst = { + .smp_prepare_cpus = r9a06g032_smp_prepare_cpus, + .smp_boot_secondary = r9a06g032_smp_boot_secondary, +}; + +CPU_METHOD_OF_DECLARE(r9a06g032_smp, + "renesas,r9a06g032-smp", &r9a06g032_smp_ops); |