linux-kernel - [PATCH v9 2/4] PCI: brcmstb: Set reasonable value for internal bus timeout

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Message-Id: <20240403213902.26391-3-james.quinlan@broadcom.com>
Date: Wed,  3 Apr 2024 17:38:59 -0400
From: Jim Quinlan <james.quinlan@...adcom.com>
To: linux-pci@...r.kernel.org,
	Nicolas Saenz Julienne <nsaenz@...nel.org>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
	Cyril Brulebois <kibi@...ian.org>,
	Phil Elwell <phil@...pberrypi.com>,
	bcm-kernel-feedback-list@...adcom.com,
	james.quinlan@...adcom.com
Cc: Florian Fainelli <florian.fainelli@...adcom.com>,
	Jim Quinlan <jim2101024@...il.com>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Krzysztof Wilczyński <kw@...ux.com>,
	Rob Herring <robh@...nel.org>,
	linux-rpi-kernel@...ts.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE),
	linux-arm-kernel@...ts.infradead.org (moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE),
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v9 2/4] PCI: brcmstb: Set reasonable value for internal bus timeout

HW initializes an internal bus timeout register to a small value for
debugging convenience.  Set this to something reasonable, i.e. in the
vicinity of 10 msec.

Signed-off-by: Jim Quinlan <james.quinlan@...adcom.com>
---
 drivers/pci/controller/pcie-brcmstb.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index f9dd6622fe10..e3480ca4cd57 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -664,6 +664,21 @@ static int brcm_pcie_enable_msi(struct brcm_pcie *pcie)
 	return 0;
 }
 
+/*
+ * An internal HW bus timer value is set to a small value for debugging
+ * convenience.  Set this to something reasonable, i.e. somewhere around
+ * 10ms.
+ */
+static void brcm_extend_internal_bus_timeout(struct brcm_pcie *pcie, u32 nsec)
+{
+	/* TIMEOUT register is two registers before RGR1_SW_INIT_1 */
+	const unsigned int REG_OFFSET = PCIE_RGR1_SW_INIT_1(pcie) - 8;
+	u32 timeout_us = nsec / 1000;
+
+	/* Each unit in timeout register is 1/216,000,000 seconds */
+	writel(216 * timeout_us, pcie->base + REG_OFFSET);
+}
+
 /* The controller is capable of serving in both RC and EP roles */
 static bool brcm_pcie_rc_mode(struct brcm_pcie *pcie)
 {
@@ -1059,6 +1074,9 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie)
 		return -ENODEV;
 	}
 
+	/* Extend internal bus timeout to 8ms or so */
+	brcm_extend_internal_bus_timeout(pcie, SZ_8M);
+
 	if (pcie->gen)
 		brcm_pcie_set_gen(pcie, pcie->gen);
 
-- 
2.17.1


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