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From: Jiang Liu <jiang.liu@linux.intel.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Randy Dunlap <rdunlap@infradead.org>,
	Yinghai Lu <yinghai@kernel.org>, Borislav Petkov <bp@alien8.de>,
	Dimitri Sivanich <sivanich@sgi.com>,
	x86@kernel.org, Jiang Liu <jiang.liu@linux.intel.com>,
	Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	David Cohen <david.a.cohen@linux.intel.com>,
	Sander Eikelenboom <linux@eikelenboom.it>,
	David Vrabel <david.vrabel@citrix.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tony Luck <tony.luck@intel.com>, Joerg Roedel <joro@8bytes.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
	linux-acpi@vger.kernel.org,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	Kuppuswamy Sathyanarayanan 
	<sathyanarayanan.kuppuswamy@linux.intel.com>
Subject: [Patch Part1 v7 29/38] x86/intel-mid: Delay initialization of APB timer
Date: Tue, 20 Jan 2015 11:08:32 +0800	[thread overview]
Message-ID: <1421723321-8386-30-git-send-email-jiang.liu@linux.intel.com> (raw)
In-Reply-To: <1421723321-8386-1-git-send-email-jiang.liu@linux.intel.com>

From: Thomas Gleixner <tglx@linutronix.de>

MID has no PIC, but depending on the platform it requires the
abt_timer, which is connected to irq0. The timer is set up at
late_time_init().

But, looking at the MID code it seems, that there is no reason to do
so. The only code which might need the timer working is the TSC
calibration code, but thats a non issue on MID as that is using its
own empty calibration function. And check_timer() is not invoked
either because MID has no PIC and therefor no legacy irqs.

So if you look at intel_mid_time_init() then you'll see that in the
ARAT case the timer setup is skipped already. So until the point where
x86_init.timers.setup_percpu_clockev() is called for the boot cpu
nothing really needs a timer on MID.

According to the MID code the apbt horror is only used for moorestown.
Medfield and later use the local apic timer without the apbt nonsense.

The best thing we can do is to drop moorestown support and get rid of
that apbt nonsense alltogether.

I don't think anyone deeply cares about it not being supported from
3.18 on. The number of devices which sport a moorestown should be
pretty limited and the only relevant use case of those is to act as a
pocket heater with short battery life time. Its pretty pointless to
update kernels on pocket heaters except for bragging reasons.

If someone at Intel really thinks that we need to keep moorestown
alive for other than documentary and sentimental reasons, then we can
move the apbt setup to x86_init.timers.setup_percpu_clockev(). At that
point the IOAPIC is setup already, so it should just work.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Cohen <david.a.cohen@linux.intel.com>
Cc: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: http://lkml.kernel.org/r/1416901802-24211-2-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 arch/x86/kernel/apb_timer.c             |    4 ----
 arch/x86/platform/intel-mid/intel-mid.c |   18 +++++++++++++-----
 arch/x86/platform/intel-mid/sfi.c       |    2 --
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index b708738d016e..7cfdc5467922 100644
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -179,10 +179,6 @@ static int __init apbt_clockevent_register(void)
 
 static void apbt_setup_irq(struct apbt_dev *adev)
 {
-	/* timer0 irq has been setup early */
-	if (adev->irq == 0)
-		return;
-
 	irq_modify_status(adev->irq, 0, IRQ_MOVE_PCNTXT);
 	irq_set_affinity(adev->irq, cpumask_of(adev->cpu));
 }
diff --git a/arch/x86/platform/intel-mid/intel-mid.c b/arch/x86/platform/intel-mid/intel-mid.c
index 1bbedc4b0f88..d8e23a622a33 100644
--- a/arch/x86/platform/intel-mid/intel-mid.c
+++ b/arch/x86/platform/intel-mid/intel-mid.c
@@ -81,26 +81,34 @@ static unsigned long __init intel_mid_calibrate_tsc(void)
 	return 0;
 }
 
+static void __init intel_mid_setup_bp_timer(void)
+{
+	apbt_time_init();
+	setup_boot_APIC_clock();
+}
+
 static void __init intel_mid_time_init(void)
 {
 	sfi_table_parse(SFI_SIG_MTMR, NULL, NULL, sfi_parse_mtmr);
+
 	switch (intel_mid_timer_options) {
 	case INTEL_MID_TIMER_APBT_ONLY:
 		break;
 	case INTEL_MID_TIMER_LAPIC_APBT:
-		x86_init.timers.setup_percpu_clockev = setup_boot_APIC_clock;
+		/* Use apbt and local apic */
+		x86_init.timers.setup_percpu_clockev = intel_mid_setup_bp_timer;
 		x86_cpuinit.setup_percpu_clockev = setup_secondary_APIC_clock;
-		break;
+		return;
 	default:
 		if (!boot_cpu_has(X86_FEATURE_ARAT))
 			break;
+		/* Lapic only, no apbt */
 		x86_init.timers.setup_percpu_clockev = setup_boot_APIC_clock;
 		x86_cpuinit.setup_percpu_clockev = setup_secondary_APIC_clock;
 		return;
 	}
-	/* we need at least one APB timer */
-	pre_init_apic_IRQ0();
-	apbt_time_init();
+
+	x86_init.timers.setup_percpu_clockev = apbt_time_init;
 }
 
 static void intel_mid_arch_setup(void)
diff --git a/arch/x86/platform/intel-mid/sfi.c b/arch/x86/platform/intel-mid/sfi.c
index c14ad34776c4..aa59f88868f8 100644
--- a/arch/x86/platform/intel-mid/sfi.c
+++ b/arch/x86/platform/intel-mid/sfi.c
@@ -95,8 +95,6 @@ int __init sfi_parse_mtmr(struct sfi_table_header *table)
 		pr_debug("timer[%d]: paddr = 0x%08x, freq = %dHz, irq = %d\n",
 			totallen, (u32)pentry->phys_addr,
 			pentry->freq_hz, pentry->irq);
-			if (!pentry->irq)
-				continue;
 			mp_irq.type = MP_INTSRC;
 			mp_irq.irqtype = mp_INT;
 /* triggering mode edge bit 2-3, active high polarity bit 0-1 */
-- 
1.7.10.4


  parent reply	other threads:[~2015-01-20  3:12 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-20  3:08 [Patch Part1 v7 00/38] Convert x86 to hierarchy irqdomain and stacked irqchip Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 01/38] x86/irq: Save destination CPU ID in irq_cfg Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 02/38] x86/irq: Use hierarchy irqdomain to manage CPU interrupt vectors Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 03/38] x86/hpet: Use new irqdomain interfaces to allocate/free IRQ Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 04/38] x86/MSI: " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 05/38] x86/uv: " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 06/38] x86/htirq: " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 07/38] x86/dmar: " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 08/38] irq_remapping: Introduce new interfaces to support hierarchy irqdomain Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 09/38] irq_remapping/vt-d: Change prototypes to prepare for enabling " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 10/38] irq_remapping/vt-d: Enhance Intel IR driver to suppport " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 11/38] irq_remapping/amd: Enhance AMD " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 12/38] x86/hpet: Enhance HPET IRQ to support " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 13/38] x86/MSI: Use hierarchy irqdomain to manage MSI interrupts Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 14/38] x86/irq: Directly call native_compose_msi_msg() for DMAR IRQ Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 15/38] irq_remapping/vt-d: Clean up unused MSI related code Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 16/38] irq_remapping/amd: " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 17/38] irq_remapping: " Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 18/38] x86/MSI: Clean up unused MSI related code and interfaces Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 19/38] iommu/vt-d: Refine the interfaces to create IRQ for DMAR unit Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 20/38] x86/irq: Use hierarchy irqdomain to manage DMAR interrupts Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 21/38] x86/htirq: Use hierarchy irqdomain to manage Hypertransport interrupts Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 22/38] x86/uv: Use hierarchy irqdomain to manage UV interrupts Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 23/38] x86/irq: Normalize x86 irq_chip name Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 24/38] x86/MSI: Simplify the way to deal with remapped MSI interrupts Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 25/38] x86/MSI: Replace msi_update_msg() with irq_chip_compose_msi_msg() Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 26/38] x86/irq: Implement irq_chip.irq_write_msi_msg for MSI/DMAR/HPET irq_chips Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 27/38] x86/irq: Simplify MSI/DMAR/HPET implementation by using common code Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 28/38] irq_remapping: Kill unused function irq_remapping_print_chip() Jiang Liu
2015-01-20  3:08 ` Jiang Liu [this message]
2015-01-20  3:08 ` [Patch Part1 v7 30/38] x86/intel-mid, trivial: Refine code syntax for sfi_parse_mtmr() Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 31/38] x86/apb_timer: Remove unused function is_apbt_capable() Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 32/38] x86/irq: Kill unused pre_init_apic_IRQ0() Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 33/38] x86/irq: Prepare IOAPIC interfaces to support hierarchy irqdomain Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 34/38] x86/irq: Implement callbacks to enable hierarchy irqdomain on IOAPICs Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 35/38] x86/irq: Refine the way to allocate irq_cfg for legacy IRQs Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 36/38] x86/irq: Simplify the way to print IOAPIC entry Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 37/38] x86/irq: Introduce helper functions to support hierarchy irqdomain for IOAPIC Jiang Liu
2015-01-20  3:08 ` [Patch Part1 v7 38/38] x86/irq: Convert IOAPIC to use hierarchy irqdomain interfaces Jiang Liu
2015-02-03  2:51 ` [Patch Part1 v7 00/38] Convert x86 to hierarchy irqdomain and stacked irqchip Jiang Liu

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