linux-kernel - [PATCH v4 20/25] PCI/PME: Use PCI_POSSIBLE

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Message-Id: <679ce049bccf10df3ca9ef4918ee2c3235afdaea.1637243717.git.naveennaidu479@gmail.com>
Date:   Thu, 18 Nov 2021 19:33:30 +0530
From:   Naveen Naidu <naveennaidu479@...il.com>
To:     bhelgaas@...gle.com
Cc:     Naveen Naidu <naveennaidu479@...il.com>,
        linux-kernel-mentees@...ts.linuxfoundation.org,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        skhan@...uxfoundation.org, Sean V Kelley <sean.v.kelley@...el.com>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Qiuxu Zhuo <qiuxu.zhuo@...el.com>
Subject: [PATCH v4 20/25] PCI/PME: Use PCI_POSSIBLE_ERROR() to check read from hardware

An MMIO read from a PCI device that doesn't exist or doesn't respond
causes a PCI error.  There's no real data to return to satisfy the
CPU read, so most hardware fabricates ~0 data.

Use PCI_POSSIBLE_ERROR() to check the response we get when we read
data from hardware.

This helps unify PCI error response checking and make error checks
consistent and easier to find.

Compile tested only.

Signed-off-by: Naveen Naidu <naveennaidu479@...il.com>
---
 drivers/pci/pcie/pme.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/pme.c b/drivers/pci/pcie/pme.c
index 1d0dd77fed3a..ef8ce436ead9 100644
--- a/drivers/pci/pcie/pme.c
+++ b/drivers/pci/pcie/pme.c
@@ -224,7 +224,7 @@ static void pcie_pme_work_fn(struct work_struct *work)
 			break;
 
 		pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
-		if (rtsta == (u32) ~0)
+		if (PCI_POSSIBLE_ERROR(rtsta))
 			break;
 
 		if (rtsta & PCI_EXP_RTSTA_PME) {
@@ -274,7 +274,7 @@ static irqreturn_t pcie_pme_irq(int irq, void *context)
 	spin_lock_irqsave(&data->lock, flags);
 	pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
 
-	if (rtsta == (u32) ~0 || !(rtsta & PCI_EXP_RTSTA_PME)) {
+	if (PCI_POSSIBLE_ERROR(rtsta) || !(rtsta & PCI_EXP_RTSTA_PME)) {
 		spin_unlock_irqrestore(&data->lock, flags);
 		return IRQ_NONE;
 	}
-- 
2.25.1