From: Jim Quinlan <jim2101024@gmail.com>
To: linux-pci@vger.kernel.org,
Nicolas Saenz Julienne <nsaenz@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Cyril Brulebois <kibi@debian.org>,
bcm-kernel-feedback-list@broadcom.com, jim2101024@gmail.com,
james.quinlan@broadcom.com
Cc: "Florian Fainelli" <f.fainelli@gmail.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
linux-rpi-kernel@lists.infradead.org (moderated list:BROADCOM
BCM2711/BCM2835 ARM ARCHITECTURE),
linux-arm-kernel@lists.infradead.org (moderated list:BROADCOM
BCM2711/BCM2835 ARM ARCHITECTURE),
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v1 2/5] PCI: brcmstb: Wait for 100ms following PERST# deassert
Date: Thu, 6 Oct 2022 18:03:18 -0400 [thread overview]
Message-ID: <20221006220322.33000-3-jim2101024@gmail.com> (raw)
In-Reply-To: <20221006220322.33000-1-jim2101024@gmail.com>
Be prudent and give some time for power and clocks to become stable. As
described in the PCIe CEM specification sections 2.2 and 2.2.1; as well as
PCIe r5.0, 6.6.1.
Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
---
drivers/pci/controller/pcie-brcmstb.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index a45ce7d61847..39b545713ba0 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -1037,8 +1037,15 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie)
pcie->perst_set(pcie, 0);
/*
- * Give the RC/EP time to wake up, before trying to configure RC.
- * Intermittently check status for link-up, up to a total of 100ms.
+ * Wait for 100ms after PERST# deassertion; see PCIe CEM specification
+ * sections 2.2, PCIe r5.0, 6.6.1.
+ */
+ msleep(100);
+
+ /*
+ * Give the RC/EP even more time to wake up, before trying to
+ * configure RC. Intermittently check status for link-up, up to a
+ * total of 100ms.
*/
for (i = 0; i < 100 && !brcm_pcie_link_up(pcie); i += 5)
msleep(5);
--
2.17.1
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next prev parent reply other threads:[~2022-10-06 22:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-06 22:03 [PATCH v1 0/5] PCI: brcmstb: Add Multi-MSI and some improvements Jim Quinlan
2022-10-06 22:03 ` [PATCH v1 1/5] PCI: brcmstb: Enable Multi-MSI Jim Quinlan
2022-10-07 19:36 ` Florian Fainelli
2022-10-10 18:04 ` Florian Fainelli
2022-10-06 22:03 ` Jim Quinlan [this message]
2022-10-06 22:12 ` [PATCH v1 2/5] PCI: brcmstb: Wait for 100ms following PERST# deassert Florian Fainelli
2022-10-06 22:03 ` [PATCH v1 3/5] PCI: brcmstb: Replace status loops with read_poll_timeout_atomic() Jim Quinlan
2022-10-06 22:15 ` Florian Fainelli
2022-10-06 22:03 ` [PATCH v1 4/5] PCI: brcmstb: Functions needlessly specified as "inline" Jim Quinlan
2022-10-06 22:09 ` Florian Fainelli
2022-10-06 22:03 ` [PATCH v1 5/5] PCI: brcmstb: Set RCB_{MPS,64B}_MODE bits Jim Quinlan
2022-10-06 22:15 ` Florian Fainelli
2022-10-07 19:32 ` Bjorn Helgaas
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