From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pali =?utf-8?B?Um9ow6Fy?= Date: Thu, 24 Sep 2020 00:47:52 +0200 Subject: [PATCH] arm64: a37xx: pci: Disable link training when unloading driver In-Reply-To: References: <20200922112138.4392-1-pali@kernel.org> Message-ID: <20200923224752.asjwdv7itdor66ur@pali> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Wednesday 23 September 2020 08:45:20 Stefan Roese wrote: > On 22.09.20 13:21, Pali Roh?r wrote: > > As required by PCI Express spec a delay for at least 100ms after > > de-asserting PERST# signal is needed before link training is enabled. > > > > Linux kernels prior to 5.8 version do not automatically disable link > > training before de-asserting PERST# signal, therefore this requirement is > > not fulfilled. > > > > Above requirement is needed for proper detection of some Compex PCIe WiFi > > cards. Otherwise Linux kernel cannot detect it. > > > > To allow using those PCIe cards with older Linux kernel versions booted by > > U-Boot compiled with U-Boot a37xx pci driver, disable link training in > > U-Boot when unloading this pci driver. > > > > Thanks to DM_FLAG_OS_PREPARE flag, U-Boot automatically unload this driver > > when booting Linux kernel. > > > > Signed-off-by: Pali Roh?r > > Reviewed-by: Stefan Roese > > Thanks, > Stefan Ok! Stefan, will you send this patch to main u-boot, so it would be part of the u-boot 2020.10 release? > > --- > > drivers/pci/pci-aardvark.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/drivers/pci/pci-aardvark.c b/drivers/pci/pci-aardvark.c > > index b2c417701f..babb84ca93 100644 > > --- a/drivers/pci/pci-aardvark.c > > +++ b/drivers/pci/pci-aardvark.c > > @@ -647,10 +647,15 @@ static int pcie_advk_probe(struct udevice *dev) > > static int pcie_advk_remove(struct udevice *dev) > > { > > struct pcie_advk *pcie = dev_get_priv(dev); > > + u32 reg; > > if (dm_gpio_is_valid(&pcie->reset_gpio)) > > dm_gpio_set_value(&pcie->reset_gpio, 1); > > + reg = advk_readl(pcie, PCIE_CORE_CTRL0_REG); > > + reg &= ~LINK_TRAINING_EN; > > + advk_writel(pcie, reg, PCIE_CORE_CTRL0_REG); > > + > > return 0; > > } > > > > > Viele Gr??e, > Stefan > > -- > DENX Software Engineering GmbH, Managing Director: Wolfgang Denk > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr at denx.de