[PATCH 5.15 114/135] PCI: aardvark: Assert PERST# when unbinding driver

Greg Kroah-Hartman
2022-05-10T14:18:56Z

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From: Pali Rohár <pali@kernel.org>

commit 1f54391be8ce0c981d312cb93acdc5608def576a upstream.

Put the PCIe card into reset by asserting PERST# signal when unbinding
driver. It doesn't make sense to leave the card working if it can't
communicate with the host. This should also save some power.

Link: https://lore.kernel.org/r/20211130172913.9727-10-kabel@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/pci/controller/pci-aardvark.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1721,6 +1721,10 @@ static int advk_pcie_remove(struct platf
/* Free config space for emulated root bridge */
pci_bridge_emul_cleanup(&pcie->bridge);

+ /* Assert PERST# signal which prepares PCIe card for power down */
+ if (pcie->reset_gpio)
+ gpiod_set_value_cansleep(pcie->reset_gpio, 1);
+
/* Disable outbound address windows mapping */
for (i = 0; i < OB_WIN_COUNT; i++)
advk_pcie_disable_ob_win(pcie, i);