Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757204AbaD1VMU (ORCPT ); Mon, 28 Apr 2014 17:12:20 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:56347 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757189AbaD1VMR (ORCPT ); Mon, 28 Apr 2014 17:12:17 -0400 From: Sebastian Hesselbarth To: Sebastian Hesselbarth Cc: Jason Cooper , Andrew Lunn , Gregory Clement , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 3/3] irqchip: orion: reverse irq handling priority Date: Mon, 28 Apr 2014 23:12:08 +0200 Message-Id: <1398719528-23607-1-git-send-email-sebastian.hesselbarth@gmail.com> In-Reply-To: <1398540855-27367-4-git-send-email-sebastian.hesselbarth@gmail.com> References: <1398540855-27367-4-git-send-email-sebastian.hesselbarth@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Non-DT irq handlers were working through irq causes from most-significant to least-significant bit, while DT irqchip driver does it the other way round. This revealed some more HW issues on Kirkwood peripheral IP, where spurious sdio irqs can happen although irqs are masked. Also, the generated binaries show that original non-DT order compared to DT order save two instructions for each bit count check: irqchip DT order with ffs(): 60: e3a06001 mov r6, #1 64: e2643000 rsb r3, r4, #0 68: e0033004 and r3, r3, r4 6c: e16f3f13 clz r3, r3 70: e263301f rsb r3, r3, #31 74: e1c44316 bic r4, r4, r6, lsl r3 78: e5971004 ldr r1, [r7, #4] Original non-DT order with fls(): 60: e3a07001 mov r7, #1 64: e16f3f14 clz r3, r4 68: e263301f rsb r3, r3, #31 6c: e1c44317 bic r4, r4, r7, lsl r3 70: e5951004 ldr r1, [r5, #4] Therefore, reverse irq bit handling back to original order by replacing ffs() with fls(). Signed-off-by: Sebastian Hesselbarth Acked-by: Jason Cooper --- Changelog: v1->v2: - reword commit msg to state less number of instructions Cc: Jason Cooper Cc: Andrew Lunn Cc: Gregory Clement Cc: Thomas Gleixner Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org --- drivers/irqchip/irq-orion.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/irqchip/irq-orion.c b/drivers/irqchip/irq-orion.c index e25f246cd2fb..34d18b48bb78 100644 --- a/drivers/irqchip/irq-orion.c +++ b/drivers/irqchip/irq-orion.c @@ -42,7 +42,7 @@ __exception_irq_entry orion_handle_irq(struct pt_regs *regs) u32 stat = readl_relaxed(gc->reg_base + ORION_IRQ_CAUSE) & gc->mask_cache; while (stat) { - u32 hwirq = ffs(stat) - 1; + u32 hwirq = __fls(stat); u32 irq = irq_find_mapping(orion_irq_domain, gc->irq_base + hwirq); handle_IRQ(irq, regs); @@ -117,7 +117,7 @@ static void orion_bridge_irq_handler(unsigned int irq, struct irq_desc *desc) gc->mask_cache; while (stat) { - u32 hwirq = ffs(stat) - 1; + u32 hwirq = __fls(stat); generic_handle_irq(irq_find_mapping(d, gc->irq_base + hwirq)); stat &= ~(1 << hwirq); -- 1.9.1 -- 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/