[PATCH v2] PCI: brcmstb: Restore initial fundamental reset

Phil Elwell phil at raspberrypi.com
Thu Nov 12 12:27:09 EST 2020

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 at raspberrypi.com>
Acked-by: Nicolas Saenz Julienne <nsaenzjulienne at 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 */

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