linux-kernel - [PATCH 1/4] PCI: Xilinx NWL: Fix, do not check for legacy status in while loop

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Date:   Sat, 21 Jan 2017 16:41:09 +0530
From:   Bharat Kumar Gogada <bharat.kumar.gogada@...inx.com>
To:     <bhelgaas@...gle.com>, <paul.gortmaker@...driver.com>,
        <robh@...nel.org>, <colin.king@...onical.com>,
        <linux-pci@...r.kernel.org>, <marc.zyngier@....com>
CC:     <michal.simek@...inx.com>, <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <rgummal@...inx.com>,
        <arnd@...db.de>, Bharat Kumar Gogada <bharatku@...inx.com>
Subject: [PATCH 1/4] PCI: Xilinx NWL: Fix, do not check for legacy status in while loop

- The legacy status register value for particular INTx becomes low
only after DEASSERT_INTx is received.
- Few End Points take time for sending DEASSERT_INTx, checking
legacy status register in while loop causes invoking of EP
handler continuosly until DEASSERT_INTx is received.

Signed-off-by: Bharat Kumar Gogada <bharatku@...inx.com>
---
 drivers/pci/host/pcie-xilinx-nwl.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/host/pcie-xilinx-nwl.c b/drivers/pci/host/pcie-xilinx-nwl.c
index 43eaa4a..c8b5a33 100644
--- a/drivers/pci/host/pcie-xilinx-nwl.c
+++ b/drivers/pci/host/pcie-xilinx-nwl.c
@@ -342,9 +342,10 @@ static void nwl_pcie_leg_handler(struct irq_desc *desc)
 
 	chained_irq_enter(chip, desc);
 	pcie = irq_desc_get_handler_data(desc);
+	status = nwl_bridge_readl(pcie, MSGF_LEG_STATUS) &
+				  MSGF_LEG_SR_MASKALL;
 
-	while ((status = nwl_bridge_readl(pcie, MSGF_LEG_STATUS) &
-				MSGF_LEG_SR_MASKALL) != 0) {
+	if (status != 0) {
 		for_each_set_bit(bit, &status, INTX_NUM) {
 			virq = irq_find_mapping(pcie->legacy_irq_domain,
 						bit + 1);
-- 
1.7.1