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From:   =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
To:     Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Mahesh J Salgaonkar <mahesh@linux.ibm.com>,
        "Oliver O'Halloran" <oohall@gmail.com>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Cc:     =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Subject: [PATCH 4/7] PCI/DPC: Use FIELD_GET()
Date:   Wed, 18 Oct 2023 14:32:51 +0300
Message-Id: <20231018113254.17616-5-ilpo.jarvinen@linux.intel.com>
In-Reply-To: <20231018113254.17616-1-ilpo.jarvinen@linux.intel.com>
References: <20231018113254.17616-1-ilpo.jarvinen@linux.intel.com>
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From: Bjorn Helgaas <bhelgaas@google.com>

Use FIELD_GET() to remove dependencies on the field position, i.e., the
shift value. No functional change intended.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/pci/pcie/dpc.c        | 5 +++--
 drivers/pci/quirks.c          | 2 +-
 include/uapi/linux/pci_regs.h | 1 +
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 3ceed8e3de41..a5c259ada9ea 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -9,6 +9,7 @@
 #define dev_fmt(fmt) "DPC: " fmt
 
 #include <linux/aer.h>
+#include <linux/bitfield.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
@@ -202,7 +203,7 @@ static void dpc_process_rp_pio_error(struct pci_dev *pdev)
 
 	/* Get First Error Pointer */
 	pci_read_config_word(pdev, cap + PCI_EXP_DPC_STATUS, &dpc_status);
-	first_error = (dpc_status & 0x1f00) >> 8;
+	first_error = FIELD_GET(PCI_EXP_DPC_RP_PIO_FEP, dpc_status);
 
 	for (i = 0; i < ARRAY_SIZE(rp_pio_error_string); i++) {
 		if ((status & ~mask) & (1 << i))
@@ -338,7 +339,7 @@ void pci_dpc_init(struct pci_dev *pdev)
 	/* Quirks may set dpc_rp_log_size if device or firmware is buggy */
 	if (!pdev->dpc_rp_log_size) {
 		pdev->dpc_rp_log_size =
-			(cap & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8;
+				FIELD_GET(PCI_EXP_DPC_RP_PIO_LOG_SIZE, cap);
 		if (pdev->dpc_rp_log_size < 4 || pdev->dpc_rp_log_size > 9) {
 			pci_err(pdev, "RP PIO log size %u is invalid\n",
 				pdev->dpc_rp_log_size);
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index eeec1d6f9023..a9fdc2e3f110 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -6154,7 +6154,7 @@ static void dpc_log_size(struct pci_dev *dev)
 	if (!(val & PCI_EXP_DPC_CAP_RP_EXT))
 		return;
 
-	if (!((val & PCI_EXP_DPC_RP_PIO_LOG_SIZE) >> 8)) {
+	if (FIELD_GET(PCI_EXP_DPC_RP_PIO_LOG_SIZE, val) == 0) {
 		pci_info(dev, "Overriding RP PIO Log Size to 4\n");
 		dev->dpc_rp_log_size = 4;
 	}
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 495f0ae4ecd5..2d6df02a4b93 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -1047,6 +1047,7 @@
 #define  PCI_EXP_DPC_STATUS_INTERRUPT	    0x0008 /* Interrupt Status */
 #define  PCI_EXP_DPC_RP_BUSY		    0x0010 /* Root Port Busy */
 #define  PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT 0x0060 /* Trig Reason Extension */
+#define  PCI_EXP_DPC_RP_PIO_FEP		    0x1f00 /* Root Port PIO First Error Pointer */
 
 #define PCI_EXP_DPC_SOURCE_ID		 0x0A	/* DPC Source Identifier */
 
-- 
2.30.2