Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932305AbaAWRyf (ORCPT ); Thu, 23 Jan 2014 12:54:35 -0500 Received: from fw-tnat.austin.arm.com ([217.140.110.23]:34606 "EHLO collaborate-mta1.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753415AbaAWRye (ORCPT ); Thu, 23 Jan 2014 12:54:34 -0500 Message-ID: <52E15756.4060705@arm.com> Date: Thu, 23 Jan 2014 17:54:30 +0000 From: Marc Zyngier User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130330 Thunderbird/17.0.5 MIME-Version: 1.0 To: Hanjun Guo CC: "Rafael J. Wysocki" , Catalin Marinas , Will Deacon , Russell King - ARM Linux , Mark Rutland , Matthew Garrett , "linaro-kernel@lists.linaro.org" , Arnd Bergmann , Rob Herring , Linus Walleij , Olof Johansson , "linux-kernel@vger.kernel.org" , "linaro-acpi@lists.linaro.org" , "linux-acpi@vger.kernel.org" , "patches@linaro.org" , "grant.likely@linaro.org" , Bjorn Helgaas , "linux-arm-kernel@lists.infradead.org" , Charles Garcia-Tobin Subject: Re: [PATCH 09/20] ARM64 / ACPI: Implement core functions for parsing MADT table References: <1389961514-13562-1-git-send-email-hanjun.guo@linaro.org> <1389961514-13562-10-git-send-email-hanjun.guo@linaro.org> In-Reply-To: <1389961514-13562-10-git-send-email-hanjun.guo@linaro.org> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Hanjun, On 17/01/14 12:25, Hanjun Guo wrote: > Implement core functions for parsing MADT table to get the information > about GIC cpu interface and GIC distributor to prepare for SMP and GIC > initialization. > > Signed-off-by: Hanjun Guo > --- > arch/arm64/include/asm/acpi.h | 3 + > drivers/acpi/plat/arm-core.c | 139 ++++++++++++++++++++++++++++++++++++++++- > drivers/acpi/tables.c | 21 +++++++ > 3 files changed, 162 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index e108d9c..c335c6d 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -83,6 +83,9 @@ void arch_fix_phys_package_id(int num, u32 slot); > extern int (*acpi_suspend_lowlevel)(void); > #define acpi_wakeup_address (0) > > +#define MAX_GIC_CPU_INTERFACE 256 I'll bite. Where on Earth is this value coming from? If that's for GICv2, 8 is the maximum. For GICv3+, that's incredibly low, and should be probed probed at runtime anyway. > +#define MAX_GIC_DISTRIBUTOR 1 /* should be the same as MAX_GIC_NR */ No support for cascaded GICs? > + > #else /* !CONFIG_ACPI */ > #define acpi_disabled 1 /* ACPI sometimes enabled on ARM */ > #define acpi_noirq 1 /* ACPI sometimes enabled on ARM */ > diff --git a/drivers/acpi/plat/arm-core.c b/drivers/acpi/plat/arm-core.c > index 1835b21..8ba3e6f 100644 > --- a/drivers/acpi/plat/arm-core.c > +++ b/drivers/acpi/plat/arm-core.c > @@ -46,6 +46,16 @@ EXPORT_SYMBOL(acpi_disabled); > int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ initialization */ > EXPORT_SYMBOL(acpi_pci_disabled); > > +/* > + * Local interrupt controller address, > + * GIC cpu interface base address on ARM/ARM64 > + */ > +static u64 acpi_lapic_addr __initdata; If that's a GIC address, why not call it as such? > +#define BAD_MADT_ENTRY(entry, end) ( \ > + (!entry) || (unsigned long)entry + sizeof(*entry) > end || \ > + ((struct acpi_subtable_header *)entry)->length < sizeof(*entry)) > + > #define PREFIX "ACPI: " Just do: #define pr_fmt(fmt) "ACPI: " fmt and remove all the occurrences of PREFIX. > /* FIXME: this function should be moved to topology.c when it is ready */ > @@ -92,6 +102,115 @@ void __init __acpi_unmap_table(char *map, unsigned long size) > return; > } > > +static int __init acpi_parse_madt(struct acpi_table_header *table) > +{ > + struct acpi_table_madt *madt = NULL; No need to initialize this to NULL, you're doing an assignment at the next line... > + > + madt = (struct acpi_table_madt *)table; > + if (!madt) { > + pr_warn(PREFIX "Unable to map MADT\n"); There is no mapping here, please fix the message accordingly. > + return -ENODEV; > + } > + > + if (madt->address) { > + acpi_lapic_addr = (u64) madt->address; So you're updating this static variable, for the distributor and each CPU interface? /me puzzled... > + pr_info(PREFIX "Local APIC address 0x%08x\n", madt->address); Away with this APIC madness. GICC and GICD are the concepts we're all familiar with here, and using the proper terminology would certainly help reviewing these patches... > + } > + > + return 0; > +} > + > +/* > + * GIC structures on ARM are somthing like Local APIC structures on x86, > + * which means GIC cpu interfaces for GICv2/v3. Every GIC structure in > + * MADT table represents a cpu in the system. And what do you do when your GICv3 doesn't have a memory-mapped interface, but only uses system registers? > + * GIC distributor structures are somthing like IOAPIC on x86. GIC can > + * be initialized with information in this structure. > + * > + * Please refer to chapter5.2.12.14/15 of ACPI 5.0 A pointer to that documentation? > + */ > + > +static int __init > +acpi_parse_gic(struct acpi_subtable_header *header, const unsigned long end) > +{ > + struct acpi_madt_generic_interrupt *processor = NULL; > + > + processor = (struct acpi_madt_generic_interrupt *)header; > + > + if (BAD_MADT_ENTRY(processor, end)) > + return -EINVAL; > + > + acpi_table_print_madt_entry(header); > + > + return 0; > +} > + > +static int __init > +acpi_parse_gic_distributor(struct acpi_subtable_header *header, > + const unsigned long end) > +{ > + struct acpi_madt_generic_distributor *distributor = NULL; > + > + distributor = (struct acpi_madt_generic_distributor *)header; > + > + if (BAD_MADT_ENTRY(distributor, end)) > + return -EINVAL; > + > + acpi_table_print_madt_entry(header); > + > + return 0; > +} > + > +/* > + * Parse GIC cpu interface related entries in MADT > + * returns 0 on success, < 0 on error > + */ > +static int __init acpi_parse_madt_gic_entries(void) > +{ > + int count; > + > + /* > + * do a partial walk of MADT to determine how many CPUs > + * we have including disabled CPUs > + */ > + count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_INTERRUPT, > + acpi_parse_gic, MAX_GIC_CPU_INTERFACE); > + > + if (!count) { > + pr_err(PREFIX "No GIC entries present\n"); > + return -ENODEV; > + } else if (count < 0) { > + pr_err(PREFIX "Error parsing GIC entry\n"); > + return count; > + } So you do a lot of parsing to count stuff, and then discard the number of counted objects... You might as well check that there is at least one valid object and stop there. > + return 0; > +} > + > +/* > + * Parse GIC distributor related entries in MADT > + * returns 0 on success, < 0 on error > + */ > +static int __init acpi_parse_madt_gic_distributor_entries(void) > +{ > + int count; > + > + count = acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR, > + acpi_parse_gic_distributor, MAX_GIC_DISTRIBUTOR); > + > + if (!count) { > + pr_err(PREFIX "No GIC distributor entries present\n"); > + return -ENODEV; > + } else if (count < 0) { > + pr_err(PREFIX "Error parsing GIC distributor entry\n"); > + return count; > + } > + > + return 0; > +} > + > int acpi_gsi_to_irq(u32 gsi, unsigned int *irq) > { > *irq = gsi_to_irq(gsi); > @@ -141,11 +260,29 @@ static int __init acpi_parse_fadt(struct acpi_table_header *table) > > static void __init early_acpi_process_madt(void) > { > - return; > + acpi_table_parse(ACPI_SIG_MADT, acpi_parse_madt); > } > > static void __init acpi_process_madt(void) > { > + int error; > + > + if (!acpi_table_parse(ACPI_SIG_MADT, acpi_parse_madt)) { How many times are you going to parse the same table? Surely you can stash whatever information you need and be done with it? > + /* > + * Parse MADT GIC cpu interface entries > + */ > + error = acpi_parse_madt_gic_entries(); > + if (!error) { > + /* > + * Parse MADT GIC distributor entries > + */ > + acpi_parse_madt_gic_distributor_entries(); > + } > + } > + > + pr_info("Using ACPI for processor (GIC) configuration information\n"); > + > return; > } > > diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c > index d67a1fe..b3e4615 100644 > --- a/drivers/acpi/tables.c > +++ b/drivers/acpi/tables.c > @@ -191,6 +191,27 @@ void acpi_table_print_madt_entry(struct acpi_subtable_header *header) > } > break; > > + case ACPI_MADT_TYPE_GENERIC_INTERRUPT: > + { > + struct acpi_madt_generic_interrupt *p = > + (struct acpi_madt_generic_interrupt *)header; > + printk(KERN_INFO PREFIX Use pr_info > + "GIC (acpi_id[0x%04x] gic_id[0x%04x] %s)\n", > + p->uid, p->gic_id, > + (p->flags & ACPI_MADT_ENABLED) ? "enabled" : "disabled"); > + } > + break; > + > + case ACPI_MADT_TYPE_GENERIC_DISTRIBUTOR: > + { > + struct acpi_madt_generic_distributor *p = > + (struct acpi_madt_generic_distributor *)header; > + printk(KERN_INFO PREFIX > + "GIC Distributor (id[0x%04x] address[0x%08llx] gsi_base[%d])\n", > + p->gic_id, p->base_address, p->global_irq_base); > + } > + break; > + > default: > printk(KERN_WARNING PREFIX > "Found unsupported MADT entry (type = 0x%x)\n", > Most of that code seems to be repeatedly parsing and printing stuff, and I fail to see what it actually does. M. -- Jazz is not dead. It just smells funny... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/