From e310b87c1a7dddb1d004412f435cb3b95fdab187 Mon Sep 17 00:00:00 2001 From: Stewart Smith Date: Fri, 17 Dec 2021 12:36:39 +1000 Subject: Introduce hwprobe facility to avoid hard-coding probe functions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit hwprobe is a little system to have different hardware probing modules run in the dependency order they choose rather than hard coding that order in core/init.c. Reviewed-by: Dan Horák Signed-off-by: Stewart Smith Signed-off-by: Cédric Le Goater --- core/Makefile.inc | 1 + core/hwprobe.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ core/init.c | 3 +++ include/skiboot.h | 39 ++++++++++++++++++++++++++++++- skiboot.lds.S | 6 +++++ 5 files changed, 118 insertions(+), 1 deletion(-) create mode 100644 core/hwprobe.c diff --git a/core/Makefile.inc b/core/Makefile.inc index 829800e..f80019b 100644 --- a/core/Makefile.inc +++ b/core/Makefile.inc @@ -13,6 +13,7 @@ CORE_OBJS += timer.o i2c.o rtc.o flash.o sensor.o ipmi-opal.o CORE_OBJS += flash-subpartition.o bitmap.o buddy.o pci-quirk.o powercap.o psr.o CORE_OBJS += pci-dt-slot.o direct-controls.o cpufeatures.o CORE_OBJS += flash-firmware-versions.o opal-dump.o +CORE_OBJS += hwprobe.o ifeq ($(SKIBOOT_GCOV),1) CORE_OBJS += gcov-profiling.o diff --git a/core/hwprobe.c b/core/hwprobe.c new file mode 100644 index 0000000..0a641ad --- /dev/null +++ b/core/hwprobe.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* Copyright 2021 Stewart Smith */ + +#define pr_fmt(fmt) "HWPROBE: " fmt +#include +#include + +static bool hwprobe_deps_satisfied(const struct hwprobe *hwp) +{ + struct hwprobe *hwprobe; + const char **dep; + unsigned int i; + + dep = hwp->deps; + if (dep == NULL) + return true; + + + prlog(PR_TRACE, "Checking deps for %s\n", hwp->name); + + while (*dep != NULL) { + prlog(PR_TRACE, "Checking %s dep %s\n", hwp->name, *dep); + hwprobe = &__hwprobes_start; + for (i = 0; &hwprobe[i] < &__hwprobes_end; i++) { + if(strcmp(hwprobe[i].name, *dep) == 0 && + !hwprobe[i].probed) + return false; + } + dep++; + } + + prlog(PR_TRACE, "deps for %s are satisfied!\n", hwp->name); + return true; + +} + +void probe_hardware(void) +{ + struct hwprobe *hwprobe; + unsigned int i; + bool work_todo = true; + bool did_something = true; + + while (work_todo) { + work_todo = false; + did_something = false; + hwprobe = &__hwprobes_start; + prlog(PR_DEBUG, "Begin loop\n"); + for (i = 0; &hwprobe[i] < &__hwprobes_end; i++) { + if (hwprobe[i].probed) + continue; + if (hwprobe_deps_satisfied(&hwprobe[i])) { + prlog(PR_DEBUG, "Probing %s...\n", hwprobe[i].name); + if (hwprobe[i].probe) + hwprobe[i].probe(); + did_something = true; + hwprobe[i].probed = true; + } else { + prlog(PR_DEBUG, "Dependencies for %s not yet satisfied, skipping\n", + hwprobe[i].name); + work_todo = true; + } + } + + if (work_todo && !did_something) { + prlog(PR_ERR, "Cannot satisfy dependencies! Bailing out\n"); + break; + } + } +} diff --git a/core/init.c b/core/init.c index aab0e90..5c2bd7f 100644 --- a/core/init.c +++ b/core/init.c @@ -1374,6 +1374,9 @@ void __noreturn __nomcount main_cpu_entry(const void *fdt) /* Probe PAUs */ probe_pau(); + /* Probe all HWPROBE hardware we have code linked for*/ + probe_hardware(); + /* Initialize PCI */ pci_init_slots(); diff --git a/include/skiboot.h b/include/skiboot.h index 312a436..d1553c4 100644 --- a/include/skiboot.h +++ b/include/skiboot.h @@ -1,5 +1,7 @@ // SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later -/* Copyright 2013-2019 IBM Corp. */ +/* Copyright 2013-2019 IBM Corp. + * Copyright 2021 Stewart Smith + */ #ifndef __SKIBOOT_H #define __SKIBOOT_H @@ -346,4 +348,39 @@ extern int fake_nvram_info(uint32_t *total_size); extern int fake_nvram_start_read(void *dst, uint32_t src, uint32_t len); extern int fake_nvram_write(uint32_t offset, void *src, uint32_t size); +/* + * A bunch of hardware needs to be probed, sometimes in a particular order. + * Very simple dependency graph, with a even simpler way to resolve it. + * But it means we can now at link time choose what hardware we support. + * This struct should not be defined directly but with the macros. + */ +struct hwprobe { + const char *name; + void (*probe)(void); + + bool probed; + + /* NULL or NULL-terminated array of strings */ + const char **deps; +}; + +#define DEFINE_HWPROBE(__name, __probe) \ +static const struct hwprobe __used __section(".hwprobes") hwprobe_##__name = { \ + .name = #__name, \ + .probe = __probe, \ + .deps = NULL, \ +} + +#define DEFINE_HWPROBE_DEPS(__name, __probe, ...) \ +static const struct hwprobe __used __section(".hwprobes") hwprobe_##__name = { \ + .name = #__name, \ + .probe = __probe, \ + .deps = (const char *[]){ __VA_ARGS__, NULL}, \ +} + +extern struct hwprobe __hwprobes_start; +extern struct hwprobe __hwprobes_end; + +extern void probe_hardware(void); + #endif /* __SKIBOOT_H */ diff --git a/skiboot.lds.S b/skiboot.lds.S index 1161384..058848f 100644 --- a/skiboot.lds.S +++ b/skiboot.lds.S @@ -166,6 +166,12 @@ SECTIONS __platforms_end = .; } + .hwprobes : { + __hwprobes_start = .; + KEEP(*(.hwprobes)) + __hwprobes_end = .; + } + /* Relocations */ . = ALIGN(0x10); .dynamic : { -- cgit v1.1