From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manikanta Maddireddy Subject: Re: [PATCH V3 01/12] PCI: tegra: Start LTSSM after programming root port Date: Wed, 13 Dec 2017 22:02:02 +0530 Message-ID: References: <1509371843-22931-1-git-send-email-mmaddireddy@nvidia.com> <1509371843-22931-2-git-send-email-mmaddireddy@nvidia.com> <20171212113248.GA30799@e107981-ln.cambridge.arm.com> <7d3396dc-b133-5645-24da-a20fd9db6286@nvidia.com> <20171213140848.GA1736@red-moon> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20171213140848.GA1736@red-moon> Content-Language: en-US Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lorenzo Pieralisi Cc: thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, vidyas-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, mperttunen-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kthota-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On 13-Dec-17 7:38 PM, Lorenzo Pieralisi wrote: > On Wed, Dec 13, 2017 at 05:20:39PM +0530, Manikanta Maddireddy wrote: >> >> >> On 12-Dec-17 5:02 PM, Lorenzo Pieralisi wrote: >>> On Mon, Oct 30, 2017 at 07:27:12PM +0530, Manikanta Maddireddy wrote: >>>> This patch ensures that LTSSM is started (by deasserting pcie_xrst) only >>>> after all the required root port register programming is completed. >>>> >>>> Signed-off-by: Manikanta Maddireddy >>>> --- >>>> V3: >>>> * no change in this patch >>>> V2: >>>> * no change in this patch >>>> >>>> drivers/pci/host/pci-tegra.c | 9 +++++---- >>>> 1 file changed, 5 insertions(+), 4 deletions(-) >>>> >>>> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c >>>> index 96e8038c3019..b41c60c7414c 100644 >>>> --- a/drivers/pci/host/pci-tegra.c >>>> +++ b/drivers/pci/host/pci-tegra.c >>>> @@ -1024,9 +1024,6 @@ static int tegra_pcie_enable_controller(struct tegra_pcie *pcie) >>>> } >>>> } >>>> >>>> - /* take the PCIe interface module out of reset */ >>>> - reset_control_deassert(pcie->pcie_xrst); >>>> - >>>> /* finally enable PCIe */ >>>> value = afi_readl(pcie, AFI_CONFIGURATION); >>>> value |= AFI_CONFIGURATION_EN_FPCI; >>>> @@ -1065,7 +1062,6 @@ static void tegra_pcie_power_off(struct tegra_pcie *pcie) >>>> dev_err(dev, "failed to power off PHY(s): %d\n", err); >>>> } >>>> >>>> - reset_control_assert(pcie->pcie_xrst); >>> >>> This does not look like it is part of the reset de-assertion code move. >>> >>> tegra_pcie_enable_controller() -> tegra_pcie_enable_ports() >>> >>> in other words, why are you removing it ? >>> >>> Lorenzo >> >> Hi Lorenzo, >> >> Host driver should start LTSSM after programming all controller registers. >> In tegra_pcie_enable_controller() bunch of AFI module programming is done and >> I am adding PCIe register programming in this series. >> So I moved deasserting of pcie_xrst(which starts LTSSM) to tegra_pcie_enable_ports(), >> which is right after sending RST pulse(tegra_pcie_port_reset()) to endpoint. > > I asked why you removed the reset assertion in tegra_pcie_power_off(), > it is not clear to me. You still call tegra_pcie_power_off() in > the tegra_pcie_probe() error path and I see no reason why the reset > assertion - called through: > > tegra_pcie_put_resources() > -> tegra_pcie_power_of() > > is removed, if it was needed previously. > > Lorenzo > New sequence with this patch will be tegra_pcie_enable_controller() -> tegra_pcie_request_resources() -> tegra_pcie_enable_ports() ->goto put_resources on fail -> reset_control_deassert(pcie->pcie_xrst); Since pcie_xrst deassert happens after tegra_pcie_request_resources(), there is no need to assert pcie_xrst on put_resource failure. >>>> reset_control_assert(pcie->afi_rst); >>>> reset_control_assert(pcie->pex_rst); >>>> >>>> @@ -2116,7 +2112,12 @@ static void tegra_pcie_enable_ports(struct tegra_pcie *pcie) >>>> port->index, port->lanes); >>>> >>>> tegra_pcie_port_enable(port); >>>> + } >>>> >>>> + /* take the PCIe interface module out of reset */ >>>> + reset_control_deassert(pcie->pcie_xrst); >>>> + >>>> + list_for_each_entry_safe(port, tmp, &pcie->ports, list) { >>>> if (tegra_pcie_port_check_link(port)) >>>> continue; >>>> >>>> -- >>>> 2.1.4 >>>> > -- > To unsubscribe from this list: send the line "unsubscribe linux-tegra" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >