[PATCH v3 28/30] arm: mach-bcm283x: Add ARMV8_MULTIENTRY support
Patrick Rudolph
patrick.rudolph at 9elements.com
Mon Sep 16 16:07:34 CEST 2024
On Thu, Sep 12, 2024 at 2:59 AM Simon Glass <sjg at chromium.org> wrote:
>
> Hi Patrick,
>
> On Wed, 11 Sept 2024 at 00:31, Patrick Rudolph
> <patrick.rudolph at 9elements.com> wrote:
> >
> > When ACPI is enabled over FDT the APs cannot be brought out of reset
> > by the OS using the "FDT spin-table" mechanism, as no FDT is provided
> > to the OS. The APs must be released out of reset in u-boot and then
> > brought up in an ACPI compliant fashion.
> >
> > When ARMV8_MULTIENTRY is specified the APs are released from reset
> > and will enter U-Boot after it has been relocated as well.
> >
> > By default ARMV8_MULTIENTRY is not selected, keeping existing behaviour.
> >
> > TEST: All APs enter U-Boot when run on qemu-system-aarch64 and on
> > real hardware.
> >
> > Signed-off-by: Patrick Rudolph <patrick.rudolph at 9elements.com>
> > Cc: Matthias Brugger <mbrugger at suse.com>
> > Cc: Peter Robinson <pbrobinson at gmail.com>
> > Cc: Tom Rini <trini at konsulko.com>
> > ---
> > Changelog v2:
> > - Drop CPU code from board
> > - Add CPU driver to release APs from reset
> >
> > ---
> > arch/arm/Kconfig | 1 +
> > arch/arm/mach-bcm283x/Kconfig | 2 +
> > arch/arm/mach-bcm283x/init.c | 8 ++
> > drivers/cpu/Makefile | 1 +
> > drivers/cpu/bcm283x_cpu.c | 194 ++++++++++++++++++++++++++++++++++
> > 5 files changed, 206 insertions(+)
> > create mode 100644 drivers/cpu/bcm283x_cpu.c
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 588e293bf2..17cd3d44b6 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -644,6 +644,7 @@ config ARCH_ORION5X
> >
> > config ARCH_BCM283X
> > bool "Broadcom BCM283X family"
> > + select CPU
> > select DM
> > select DM_GPIO
> > select DM_SERIAL
> > diff --git a/arch/arm/mach-bcm283x/Kconfig b/arch/arm/mach-bcm283x/Kconfig
> > index b3287ce8bc..de783aa8f5 100644
> > --- a/arch/arm/mach-bcm283x/Kconfig
> > +++ b/arch/arm/mach-bcm283x/Kconfig
> > @@ -12,6 +12,7 @@ config BCM2836
> > config BCM2837
> > bool "Broadcom BCM2837 SoC support"
> > depends on ARCH_BCM283X
> > + select ARCH_EARLY_INIT_R
> >
> > config BCM2837_32B
> > bool "Broadcom BCM2837 SoC 32-bit support"
> > @@ -29,6 +30,7 @@ config BCM2837_64B
> > config BCM2711
> > bool "Broadcom BCM2711 SoC support"
> > depends on ARCH_BCM283X
> > + select ARCH_EARLY_INIT_R
> >
> > config BCM2711_32B
> > bool "Broadcom BCM2711 SoC 32-bit support"
> > diff --git a/arch/arm/mach-bcm283x/init.c b/arch/arm/mach-bcm283x/init.c
> > index 7a1de22e0a..e6946c6e94 100644
> > --- a/arch/arm/mach-bcm283x/init.c
> > +++ b/arch/arm/mach-bcm283x/init.c
> > @@ -9,6 +9,7 @@
> > #include <cpu_func.h>
> > #include <init.h>
> > #include <dm/device.h>
> > +#include <dm/uclass.h>
> > #include <fdt_support.h>
> > #include <asm/global_data.h>
> >
> > @@ -199,7 +200,14 @@ int mach_cpu_init(void)
> > "brcm,bcm2712-pm");
> > if (offset > soc)
> > rpi_wdog_base = fdt_get_base_address(gd->fdt_blob, offset);
> > + return 0;
> > +}
> > +
> > +int arch_early_init_r(void)
> > +{
> > + struct udevice *dev;
> >
> > + uclass_first_device(UCLASS_CPU, &dev);
>
> blank line before final return
>
> > return 0;
>
> This is fine, but you should check for an error, right?
>
> Also there is print_cpuinfo() which should be called if CONFIG_CPU is
> enabled...it is a little later in the init sequence. Is it too late
> for your purposes?
print_cpuinfo() is called before relocation, so cannot be used to
invoke the CPU driver.
It would release the secondary CPUs and they would keep spinning in
the non relocated U-Boot code.
>
> > }
> >
> > diff --git a/drivers/cpu/Makefile b/drivers/cpu/Makefile
> > index 773395693a..5230408cc0 100644
> > --- a/drivers/cpu/Makefile
> > +++ b/drivers/cpu/Makefile
> > @@ -7,6 +7,7 @@
> > obj-$(CONFIG_CPU) += cpu-uclass.o
> >
> >
> > +obj-$(CONFIG_ARCH_BCM283X) += bcm283x_cpu.o
> > obj-$(CONFIG_ARCH_BMIPS) += bmips_cpu.o
> > obj-$(CONFIG_ARCH_IMX8) += imx8_cpu.o
> > obj-$(CONFIG_ARCH_AT91) += at91_cpu.o
> > diff --git a/drivers/cpu/bcm283x_cpu.c b/drivers/cpu/bcm283x_cpu.c
> > new file mode 100644
> > index 0000000000..11dd3008cc
> > --- /dev/null
> > +++ b/drivers/cpu/bcm283x_cpu.c
> > @@ -0,0 +1,194 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright 2024 9elements GmbH
> > + */
> > +
> > +#include <asm/cache.h>
> > +#include <asm/io.h>
> > +#include <asm/global_data.h>
> > +#include <asm/system.h>
> > +#include <asm/armv8/cpu.h>
> > +#include <asm-generic/sections.h>
> > +#include <cpu.h>
> > +#include <cpu_func.h>
> > +#include <dm.h>
> > +#include <fdt_support.h>
> > +#include <linux/bitops.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/delay.h>
> > +
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> > +static int cpu_bcm_get_desc(const struct udevice *dev, char *buf, int size)
> > +{
> > + struct cpu_plat *plat = dev_get_parent_plat(dev);
> > + const char *name;
> > + int ret;
> > +
> > + if (size < 32)
> > + return -ENOSPC;
> > +
> > + if (device_is_compatible(dev, "arm,cortex-a53"))
> > + name = "A53";
> > + else if (device_is_compatible(dev, "arm,cortex-a72"))
> > + name = "A72";
> > + else
> > + name = "?";
> > +
> > + ret = snprintf(buf, size, "Broadcom Cortex-%s at %u MHz",
> > + name, plat->timebase_freq);
> > +
> > + snprintf(buf + ret, size - ret, "\n");
>
> Can you put the \n at the end of the previous statement?
>
> > +
> > + return 0;
> > +}
> > +
> > +static int cpu_bcm_get_info(const struct udevice *dev, struct cpu_info *info)
> > +{
> > + struct cpu_plat *plat = dev_get_parent_plat(dev);
> > +
> > + info->cpu_freq = plat->timebase_freq * 1000;
> > + info->features = BIT(CPU_FEAT_L1_CACHE) | BIT(CPU_FEAT_MMU);
>
> blank line
>
> > + return 0;
> > +}
> > +
> > +static int cpu_bcm_get_count(const struct udevice *dev)
> > +{
> > + ofnode node;
> > + int num = 0;
> > +
> > + ofnode_for_each_subnode(node, dev_ofnode(dev->parent)) {
> > + const char *device_type;
> > +
> > + if (!ofnode_is_enabled(node))
> > + continue;
> > +
> > + device_type = ofnode_read_string(node, "device_type");
> > + if (!device_type)
> > + continue;
> > +
> > + if (!strcmp(device_type, "cpu"))
> > + num++;
> > + }
>
> This should really be done in the of_to_plat() method. Store it
> somewhere so this function can just return it.
>
Will add it.
> > +
> > + return num;
> > +}
> > +
> > +static int cpu_bcm_get_vendor(const struct udevice *dev, char *buf, int size)
> > +{
> > + snprintf(buf, size, "Broadcom");
>
> blank line here (please fix globally)
>
> > + return 0;
> > +}
> > +
> > +#ifdef CONFIG_ARM64
> > +static int cpu_bcm_is_current(struct udevice *dev)
> > +{
> > + struct cpu_plat *plat = dev_get_parent_plat(dev);
> > +
> > + if (plat->cpu_id == (read_mpidr() & 0xffff))
> > + return 1;
> > +
> > + return 0;
> > +}
> > +#endif
> > +
> > +static int bcm_cpu_on(struct udevice *dev)
>
> What does this do? Does it turn on the CPU? Perhaps add a comment?
>
> Also, please return 0 for success, -ve error code otherwise
>
> > +{
> > + ofnode node = dev_ofnode(dev);
> > + uintptr_t *start_address;
>
> ulong start_address
>
> > + u64 release_addr64;
>
> release_addr
>
> > + const char *prop;
> > +
> > + if (!ofnode_is_enabled(node))
> > + return 0;
>
> Hmm, but if it isn't enabled, how would this device be bound?
>
> > +
> > + prop = ofnode_read_string(node, "enable-method");
> > + if (!prop || strcmp(prop, "spin-table"))
> > + return 1;
> > +
> > + release_addr64 = ofnode_read_u64_default(node, "cpu-release-addr", ~0ULL);
> > + if (release_addr64 == ~0ULL)
> > + return 1;
>
> if (ofnode_read_u64(node, "cpu-release-addr"), &release_addr))
> return -EINVAL;
>
> > +
> > + start_address = map_physmem(release_addr64, sizeof(uintptr_t), MAP_NOCACHE);
> > +
> > + /* Point to U-Boot start */
> > + *start_address = (uintptr_t)_start;
> > + flush_dcache_all();
>
> dcache always enabled? Which is fine...just asking
>
> > +
> > + /* Send an event to wake up the secondary CPU. */
> > + asm("dsb ishst\n"
> > + "sev");
> > + udelay(10000);
> > +
> > + unmap_physmem(start_address, MAP_NOCACHE);
> > + return 0;
> > +}
> > +
> > +static int bcm_init(struct udevice *dev)
> > +{
> > + int ret = 0;
> > +
> > + /* The armstub holds the secondary CPUs in a spinloop. When
>
> /*
> * The
>
> > + * ARMV8_MULTIENTRY is enabled release the secondary CPUs and
> > + * let them enter U-Boot as well.
> > + */
> > + if (CONFIG_IS_ENABLED(ARMV8_MULTIENTRY))
> > + ret = bcm_cpu_on(dev);
> > + return ret;
>
> More U-Boot-esk:
>
> if (CONFIG_IS_ENABLED(ARMV8_MULTIENTRY)) {
> int ret;
>
> ret = bcm_cpu_on(dev);
> if (ret)
> return ret;
> }
>
> return 0;
> }
>
> > +}
> > +
> > +static const struct cpu_ops cpu_bcm_ops = {
> > + .get_desc = cpu_bcm_get_desc,
> > + .get_info = cpu_bcm_get_info,
> > + .get_count = cpu_bcm_get_count,
> > + .get_vendor = cpu_bcm_get_vendor,
> > +#ifdef CONFIG_ARM64
>
> Can just check this in the function, to avoid an #ifdef
>
> > + .is_current = cpu_bcm_is_current,
> > +#endif
> > +};
> > +
> > +static const struct udevice_id cpu_bcm_ids[] = {
> > + { .compatible = "arm,cortex-a53" }, /* RPi 3 */
> > + { .compatible = "arm,cortex-a72" }, /* RPi 4 */
> > + { }
> > +};
> > +
> > +static int cpu_bcm_bind(struct udevice *dev)
> > +{
> > + struct cpu_plat *plat = dev_get_parent_plat(dev);
> > +
> > + plat->cpu_id = dev_read_addr(dev);
>
> You should not bring up the CPUs so early. The bind() method is just
> for binding. Can this move to probe() ?
This took me a while.
The main issue here was that uclass_first_device(UCLASS_CPU, &dev); only probes
the first CPU, but not the others. That's why I used bind() in the first place.
>
> > +
> > + return bcm_init(dev);
> > +}
> > +
> > +static int bcm_cpu_probe(struct udevice *dev)
> > +{
> > + struct cpu_plat *plat = dev_get_parent_plat(dev);
> > + struct clk clk;
> > + int ret;
> > +
> > + /* Get a clock if it exists */
> > + ret = clk_get_by_index(dev, 0, &clk);
> > + if (!ret) {
> > + ret = clk_enable(&clk);
> > + if (ret && (ret != -ENOSYS || ret != -EOPNOTSUPP))
> > + return ret;
> > + ret = clk_get_rate(&clk);
> > + if (!IS_ERR_VALUE(ret))
> > + plat->timebase_freq = ret;
>
> If you get an error, you must return it
>
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +U_BOOT_DRIVER(cpu_bcm_drv) = {
> > + .name = "bcm283x_cpu",
> > + .id = UCLASS_CPU,
> > + .of_match = cpu_bcm_ids,
> > + .ops = &cpu_bcm_ops,
> > + .probe = bcm_cpu_probe,
> > + .bind = cpu_bcm_bind,
> > + .flags = 0,
> > +};
> > --
> > 2.46.0
> >
>
> Regards,
> Simon
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