/* $NetBSD: cpu_fdt.c,v 1.44 2024/05/10 14:42:21 riastradh Exp $ */

/*-
 * Copyright (c) 2017 Jared McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "opt_multiprocessor.h"
#include "psci_fdt.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cpu_fdt.c,v 1.44 2024/05/10 14:42:21 riastradh Exp $");

#include <sys/param.h>
#include <sys/atomic.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/lwp.h>
#include <sys/systm.h>
#include <sys/kernel.h>

#include <dev/fdt/fdtvar.h>

#include <arm/armreg.h>
#include <arm/cpu.h>
#include <arm/cpufunc.h>
#include <arm/cpuvar.h>
#include <arm/locore.h>

#include <arm/arm/psci.h>
#include <arm/fdt/arm_fdtvar.h>
#include <arm/fdt/psci_fdtvar.h>

#include <uvm/uvm_extern.h>

static int	cpu_fdt_match(device_t, cfdata_t, void *);
static void	cpu_fdt_attach(device_t, device_t, void *);

CFATTACH_DECL2_NEW(cpu_fdt, 0,
    cpu_fdt_match, cpu_fdt_attach, NULL, NULL,
    cpu_rescan, cpu_childdetached);

static int
cpu_fdt_match(device_t parent, cfdata_t cf, void *aux)
{
	struct fdt_attach_args * const faa = aux;
	const int phandle = faa->faa_phandle;
	const char *device_type;

	device_type = fdtbus_get_string(phandle, "device_type");

	return device_type != NULL && strcmp(device_type, "cpu") == 0;
}

static void
cpu_fdt_attach(device_t parent, device_t self, void *aux)
{
	struct fdt_attach_args * const faa = aux;
	const int phandle = faa->faa_phandle;
	bus_addr_t cpuid;
	const uint32_t *cap_ptr;
	int len;

 	cap_ptr = fdtbus_get_prop(phandle, "capacity-dmips-mhz", &len);
	if (cap_ptr && len == 4) {
		prop_dictionary_t dict = device_properties(self);
		uint32_t capacity_dmips_mhz = be32toh(*cap_ptr);

		prop_dictionary_set_uint32(dict, "capacity_dmips_mhz",
		    capacity_dmips_mhz);
	}

	if (fdtbus_get_reg(phandle, 0, &cpuid, NULL) != 0)
		cpuid = 0;

	/* Attach the CPU */
	cpu_attach(self, cpuid);

	/* Attach CPU frequency scaling provider */
	config_found(self, faa, NULL, CFARGS(.iattr = "cpu"));
}

#if defined(MULTIPROCESSOR) && (NPSCI_FDT > 0 || defined(__aarch64__))
static register_t
cpu_fdt_mpstart_pa(void)
{
	bool ok __diagused;
	paddr_t pa;

	ok = pmap_extract(pmap_kernel(), (vaddr_t)cpu_mpstart, &pa);
	KASSERT(ok);

	return pa;
}
#endif

#ifdef MULTIPROCESSOR
static bool
arm_fdt_cpu_okay(const int child)
{
	const char *s;

	s = fdtbus_get_string(child, "device_type");
	if (!s || strcmp(s, "cpu") != 0)
		return false;

	s = fdtbus_get_string(child, "status");
	if (s) {
		if (strcmp(s, "okay") == 0)
			return false;
		if (strcmp(s, "disabled") == 0)
			return of_hasprop(child, "enable-method");
		return false;
	} else {
		return true;
	}
}
#endif /* MULTIPROCESSOR */

void
arm_fdt_cpu_bootstrap(void)
{
#ifdef MULTIPROCESSOR
	uint64_t mpidr, bp_mpidr;
	u_int cpuindex;
	int child;

	const int cpus = OF_finddevice("/cpus");
	if (cpus == -1) {
		aprint_error("%s: no /cpus node found\n", __func__);
		arm_cpu_max = 1;
		return;
	}

	/* Count CPUs */
	arm_cpu_max = 0;

	/* MPIDR affinity levels of boot processor. */
	bp_mpidr = cpu_mpidr_aff_read();

	/* Add APs to cpu_mpidr array */
	cpuindex = 1;
	for (child = OF_child(cpus); child; child = OF_peer(child)) {
		if (!arm_fdt_cpu_okay(child))
			continue;

		arm_cpu_max++;
		if (fdtbus_get_reg64(child, 0, &mpidr, NULL) != 0)
			continue;
		if (mpidr == bp_mpidr)
			continue; 	/* BP already started */

		KASSERT(cpuindex < MAXCPUS);
		cpu_mpidr[cpuindex] = mpidr;
		cpu_dcache_wb_range((vaddr_t)&cpu_mpidr[cpuindex],
		    sizeof(cpu_mpidr[cpuindex]));

		cpuindex++;
	}
#endif
}

#ifdef MULTIPROCESSOR
static struct arm_cpu_method *
arm_fdt_cpu_enable_method_byname(const char *method)
{
	__link_set_decl(arm_cpu_methods, struct arm_cpu_method);
	struct arm_cpu_method * const *acmp;

	__link_set_foreach(acmp, arm_cpu_methods) {
		if (strcmp(method, (*acmp)->acm_compat) == 0)
			return *acmp;
	}

	return NULL;
}

static struct arm_cpu_method *
arm_fdt_cpu_enable_method(int phandle)
{
	const char *method;

 	method = fdtbus_get_string(phandle, "enable-method");
	if (method == NULL)
		return NULL;

	return arm_fdt_cpu_enable_method_byname(method);
}

static int
arm_fdt_cpu_enable(int phandle, struct arm_cpu_method *acm)
{
	return acm->acm_enable(phandle);
}
#endif

int
arm_fdt_cpu_mpstart(void)
{
	int ret = 0;
#ifdef MULTIPROCESSOR
	uint64_t mpidr, bp_mpidr;
	u_int cpuindex, i;
	int child, error;
	struct arm_cpu_method *acm;

	const int cpus = OF_finddevice("/cpus");
	if (cpus == -1) {
		aprint_error("%s: no /cpus node found\n", __func__);
		return 0;
	}

	/* MPIDR affinity levels of boot processor. */
	bp_mpidr = cpu_mpidr_aff_read();

	/* Boot APs */
	cpuindex = 1;
	for (child = OF_child(cpus); child; child = OF_peer(child)) {
		if (!arm_fdt_cpu_okay(child))
			continue;

		if (fdtbus_get_reg64(child, 0, &mpidr, NULL) != 0)
			continue;

		if (mpidr == bp_mpidr)
			continue; 	/* BP already started */

		acm = arm_fdt_cpu_enable_method(child);
		if (acm == NULL)
			acm = arm_fdt_cpu_enable_method(cpus);
		if (acm == NULL)
			acm = arm_fdt_cpu_enable_method_byname("psci");
		if (acm == NULL)
			continue;

		error = arm_fdt_cpu_enable(child, acm);
		if (error != 0) {
			aprint_error("%s: failed to enable CPU %#" PRIx64 "\n",
			    __func__, mpidr);
			continue;
		}

		/* Wake up AP in case firmware has placed it in WFE state */
		sev();

		/* Wait for AP to start */
		for (i = 0x10000000; i > 0; i--) {
			if (cpu_hatched_p(cpuindex))
				break;
		}

		if (i == 0) {
			ret++;
			aprint_error("cpu%d: WARNING: AP failed to start\n", cpuindex);
		}

		cpuindex++;
	}
#endif /* MULTIPROCESSOR */
	return ret;
}

static int
cpu_enable_nullop(int phandle)
{
	return ENXIO;
}
ARM_CPU_METHOD(default, "", cpu_enable_nullop);

#if defined(MULTIPROCESSOR) && NPSCI_FDT > 0
static int
cpu_enable_psci(int phandle)
{
	static bool psci_probed, psci_p;
	uint64_t mpidr;
	int ret;

	if (!psci_probed) {
		psci_probed = true;
		psci_p = psci_fdt_preinit() == 0;
	}
	if (!psci_p)
		return ENXIO;

	fdtbus_get_reg64(phandle, 0, &mpidr, NULL);

#if !defined(AARCH64)
	/*
	 * not necessary on AARCH64. beside there it hangs the system
	 * because cache ops are only functional after cpu_attach()
	 * was called.
	 */
	cpu_dcache_wbinv_all();
#endif
	ret = psci_cpu_on(mpidr, cpu_fdt_mpstart_pa(), 0);
	if (ret != PSCI_SUCCESS)
		return EIO;

	return 0;
}
ARM_CPU_METHOD(psci, "psci", cpu_enable_psci);
#endif

#if defined(MULTIPROCESSOR) && defined(__aarch64__)
static int
spintable_cpu_on(const int phandle, u_int cpuindex,
    paddr_t entry_point_address, paddr_t cpu_release_addr)
{
	/*
	 * we need devmap for cpu-release-addr in advance.
	 * __HAVE_MM_MD_DIRECT_MAPPED_PHYS nor pmap work at this point.
	 */
	if (pmap_devmap_find_pa(cpu_release_addr, sizeof(paddr_t)) == NULL) {
		aprint_error("%s: devmap for cpu-release-addr"
		    " 0x%08"PRIxPADDR" required\n", __func__, cpu_release_addr);
		return -1;
	} else {
		extern struct bus_space arm_generic_bs_tag;
		bus_space_handle_t ioh;

		const int parent = OF_parent(phandle);
		const int addr_cells = fdtbus_get_addr_cells(parent);

		bus_space_map(&arm_generic_bs_tag, cpu_release_addr,
		    sizeof(paddr_t), 0, &ioh);
		if (addr_cells == 1) {
			bus_space_write_4(&arm_generic_bs_tag, ioh, 0,
			    entry_point_address);
		} else {
			bus_space_write_8(&arm_generic_bs_tag, ioh, 0,
			    entry_point_address);
		}
		bus_space_unmap(&arm_generic_bs_tag, ioh, sizeof(paddr_t));
	}

	return 0;
}

static int
cpu_enable_spin_table(int phandle)
{
	uint64_t mpidr, addr;
	int ret;

	fdtbus_get_reg64(phandle, 0, &mpidr, NULL);

	if (of_getprop_uint64(phandle, "cpu-release-addr", &addr) != 0)
		return ENXIO;

	ret = spintable_cpu_on(phandle, mpidr, cpu_fdt_mpstart_pa(),
	    (paddr_t)addr);
	if (ret != 0)
		return EIO;

	return 0;
}
ARM_CPU_METHOD(spin_table, "spin-table", cpu_enable_spin_table);
#endif