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From: Phil Elwell <phil@raspberrypi.com>
To: Jim Quinlan <james.quinlan@broadcom.com>,
	Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	Rob Herring <robh@kernel.org>,
	Florian Fainelli <f.fainelli@gmail.com>,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org, linux-pci@vger.kernel.org
Cc: Phil Elwell <phil@raspberrypi.com>
Subject: [PATCH v2] PCI: brcmstb: Restore initial fundamental reset
Date: Thu, 12 Nov 2020 17:27:09 +0000	[thread overview]
Message-ID: <20201112172709.1817-1-phil@raspberrypi.com> (raw)

Commit 04356ac30771 ("PCI: brcmstb: Add bcm7278 PERST# support")
replaced a single reset function with a pointer to one of two
implementations, but also removed the call asserting the reset
at the start of brcm_pcie_setup. Doing so breaks Raspberry Pis with
VL805 XHCI controllers lacking dedicated SPI EEPROMs, which have been
used for USB booting but then need to be reset so that the kernel
can reconfigure them. The lack of a reset causes the firmware's loading
of the EEPROM image to RAM to fail, breaking USB for the kernel.

Fixes: commit 04356ac30771 ("PCI: brcmstb: Add bcm7278 PERST# support")

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
Changes in v2:
  - Exclude BCM7278 from the initial reset
  - Ack from Nicolas
---
 drivers/pci/controller/pcie-brcmstb.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index bea86899bd5d..83aa85bfe8e3 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -869,6 +869,11 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 
 	/* Reset the bridge */
 	pcie->bridge_sw_init_set(pcie, 1);
+
+	/* Assert the fundemental reset, except on BCM7278 */
+	if (pcie->type != BCM7278)
+		pcie->perst_set(pcie, 1);
+
 	usleep_range(100, 200);
 
 	/* Take the bridge out of reset */
-- 
2.25.1


             reply	other threads:[~2020-11-12 17:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-12 17:27 Phil Elwell [this message]
2020-11-12 18:05 ` [PATCH v2] PCI: brcmstb: Restore initial fundamental reset Stefan Wahren
2020-11-12 18:38 ` Jim Quinlan
2021-01-18 12:40   ` Lorenzo Pieralisi
2021-01-18 12:44     ` Nicolas Saenz Julienne
2021-01-18 13:33       ` Phil Elwell

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