linux-kernel - Re: [PATCH v2] dwc: dra7xx: Print link state to console for debug

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Date:   Tue, 24 Oct 2017 14:59:50 -0500
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Faiz Abbas <faiz_abbas@...com>
Cc:     kishon@...com, bhelgaas@...gle.com, linux-omap@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] dwc: dra7xx: Print link state to console for debug

On Thu, Oct 19, 2017 at 06:13:29PM +0530, Faiz Abbas wrote:
> Enable support for printing the LTSSM link state for debugging PCI
> when link is down.
> 
> Signed-off-by: Faiz Abbas <faiz_abbas@...com>

Applied with Kishon's ack to pci/host-dra7xx for v4.15, thanks!

I tweaked the "link up" testing as follows (what I suggested before):


@@ -118,8 +157,18 @@ static int dra7xx_pcie_link_up(struct dw_pcie *pci)
 {
 	struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pci);
 	u32 reg = dra7xx_pcie_readl(dra7xx, PCIECTRL_DRA7XX_CONF_PHY_CS);
+	int link_up = !!(reg & LINK_UP);
+	u32 cmd_reg;
+	u32 ltssm_state;
+
+	if (!link_up) {
+		cmd_reg = dra7xx_pcie_readl(dra7xx,
+					    PCIECTRL_DRA7XX_CONF_DEVICE_CMD);
+		ltssm_state = (cmd_reg & GENMASK(7, 2)) >> 2;
+		dev_dbg(pci->dev, "Link state: %s\n", state[ltssm_state]);
+	}
 
-	return !!(reg & LINK_UP);
+	return link_up;
 }
 
 static void dra7xx_pcie_stop_link(struct dw_pcie *pci)