linux-kernel - [PATCH v2 01/11] PCI: pci-bridge-emul: Re-arrange register tests

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Message-Id: <20220112151814.24361-2-pali@kernel.org>
Date:   Wed, 12 Jan 2022 16:18:04 +0100
From:   Pali Rohár <pali@...nel.org>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Rob Herring <robh+dt@...nel.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Krzysztof Wilczyński <kw@...ux.com>,
        Marek Behún <kabel@...nel.org>,
        Russell King <rmk+kernel@...linux.org.uk>
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v2 01/11] PCI: pci-bridge-emul: Re-arrange register tests

From: Russell King <rmk+kernel@...linux.org.uk>

Re-arrange the tests for which sets of registers are being accessed so that
it is easier to add further regions later. No functional change.

Signed-off-by: Russell King <rmk+kernel@...linux.org.uk>
[pali: Fix reading old value in pci_bridge_emul_conf_write]
Signed-off-by: Pali Rohár <pali@...nel.org>
---
 drivers/pci/pci-bridge-emul.c | 61 ++++++++++++++++++-----------------
 1 file changed, 31 insertions(+), 30 deletions(-)

diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
index 033bbeb99176..56b2cb741498 100644
--- a/drivers/pci/pci-bridge-emul.c
+++ b/drivers/pci/pci-bridge-emul.c
@@ -418,25 +418,25 @@ int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where,
 	__le32 *cfgspace;
 	const struct pci_bridge_reg_behavior *behavior;
 
-	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_END) {
-		*value = 0;
-		return PCIBIOS_SUCCESSFUL;
-	}
-
-	if (!bridge->has_pcie && reg >= PCI_BRIDGE_CONF_END) {
+	if (reg < PCI_BRIDGE_CONF_END) {
+		/* Emulated PCI space */
+		read_op = bridge->ops->read_base;
+		cfgspace = (__le32 *) &bridge->conf;
+		behavior = bridge->pci_regs_behavior;
+	} else if (!bridge->has_pcie) {
+		/* PCIe space is not implemented, and no PCI capabilities */
 		*value = 0;
 		return PCIBIOS_SUCCESSFUL;
-	}
-
-	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_START) {
+	} else if (reg < PCI_CAP_PCIE_END) {
+		/* Our emulated PCIe capability */
 		reg -= PCI_CAP_PCIE_START;
 		read_op = bridge->ops->read_pcie;
 		cfgspace = (__le32 *) &bridge->pcie_conf;
 		behavior = bridge->pcie_cap_regs_behavior;
 	} else {
-		read_op = bridge->ops->read_base;
-		cfgspace = (__le32 *) &bridge->conf;
-		behavior = bridge->pci_regs_behavior;
+		/* Beyond our PCIe space */
+		*value = 0;
+		return PCIBIOS_SUCCESSFUL;
 	}
 
 	if (read_op)
@@ -480,11 +480,27 @@ int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
 	__le32 *cfgspace;
 	const struct pci_bridge_reg_behavior *behavior;
 
-	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_END)
-		return PCIBIOS_SUCCESSFUL;
+	ret = pci_bridge_emul_conf_read(bridge, reg, 4, &old);
+	if (ret != PCIBIOS_SUCCESSFUL)
+		return ret;
 
-	if (!bridge->has_pcie && reg >= PCI_BRIDGE_CONF_END)
+	if (reg < PCI_BRIDGE_CONF_END) {
+		/* Emulated PCI space */
+		write_op = bridge->ops->write_base;
+		cfgspace = (__le32 *) &bridge->conf;
+		behavior = bridge->pci_regs_behavior;
+	} else if (!bridge->has_pcie) {
+		/* PCIe space is not implemented, and no PCI capabilities */
 		return PCIBIOS_SUCCESSFUL;
+	} else if (reg < PCI_CAP_PCIE_END) {
+		/* Our emulated PCIe capability */
+		reg -= PCI_CAP_PCIE_START;
+		write_op = bridge->ops->write_pcie;
+		cfgspace = (__le32 *) &bridge->pcie_conf;
+		behavior = bridge->pcie_cap_regs_behavior;
+	} else {
+		return PCIBIOS_SUCCESSFUL;
+	}
 
 	shift = (where & 0x3) * 8;
 
@@ -497,21 +513,6 @@ int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
 	else
 		return PCIBIOS_BAD_REGISTER_NUMBER;
 
-	ret = pci_bridge_emul_conf_read(bridge, reg, 4, &old);
-	if (ret != PCIBIOS_SUCCESSFUL)
-		return ret;
-
-	if (bridge->has_pcie && reg >= PCI_CAP_PCIE_START) {
-		reg -= PCI_CAP_PCIE_START;
-		write_op = bridge->ops->write_pcie;
-		cfgspace = (__le32 *) &bridge->pcie_conf;
-		behavior = bridge->pcie_cap_regs_behavior;
-	} else {
-		write_op = bridge->ops->write_base;
-		cfgspace = (__le32 *) &bridge->conf;
-		behavior = bridge->pci_regs_behavior;
-	}
-
 	/* Keep all bits, except the RW bits */
 	new = old & (~mask | ~behavior[reg / 4].rw);
 
-- 
2.20.1