Thread (4 messages) 4 messages, 3 authors, 2016-06-30
STALE3640d

[PATCH] pci: tegra: actually program REFCLK_CFG* on recent SoCs

From: Thierry Reding <hidden>
Date: 2016-06-30 13:47:28
Also in: linux-tegra

On Fri, Jun 24, 2016 at 08:37:03AM -0600, Stephen Warren wrote:
quoted hunk ↗ jump to hunk
From: Stephen Warren <redacted>

On recent SoCs, tegra_pcie_phy_enable() isn't called; but instead
tegra_pcie_enable_controller() calls tegra_xusb_phy_enable(). However,
part of tegra_pcie_phy_enable() needs to happen in all cases. Move that
code to tegra_pcie_port_enable() instead.

For reference, NVIDIA's downstream Linux kernel performs this operation
in tegra_pcie_enable_rp_features(), which is called immediately after
tegra_pcie_port_enable(). Since that function doesn't exist in the mainline
driver, we'll just add it to the tail of tegra_pcie_port_enable() instead.

Signed-off-by: Stephen Warren <redacted>
---
 drivers/pci/host/pci-tegra.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 74887fedc3d4..2ec64a9e7943 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -541,12 +541,13 @@ static void tegra_pcie_port_reset(struct tegra_pcie_port *port)
 
 static void tegra_pcie_port_enable(struct tegra_pcie_port *port)
 {
-	const struct tegra_pcie_soc_data *soc = port->pcie->soc_data;
+	struct tegra_pcie *pcie = port->pcie;
+	const struct tegra_pcie_soc_data *soc = pcie->soc_data;
 	unsigned long ctrl = tegra_pcie_port_get_pex_ctrl(port);
 	unsigned long value;
 
 	/* enable reference clock */
-	value = afi_readl(port->pcie, ctrl);
+	value = afi_readl(pcie, ctrl);
 	value |= AFI_PEX_CTRL_REFCLK_EN;
 
 	if (soc->has_pex_clkreq_en)
@@ -554,9 +555,14 @@ static void tegra_pcie_port_enable(struct tegra_pcie_port *port)
 
 	value |= AFI_PEX_CTRL_OVERRIDE_EN;
 
-	afi_writel(port->pcie, value, ctrl);
+	afi_writel(pcie, value, ctrl);
 
 	tegra_pcie_port_reset(port);
+
+	/* Configure the reference clock driver */
+	pads_writel(pcie, soc->pads_refclk_cfg0, PADS_REFCLK_CFG0);
+	if (soc->num_ports > 2)
+		pads_writel(pcie, soc->pads_refclk_cfg1, PADS_REFCLK_CFG1);
 }
This will actually write these two registers for each enabled port,
which, while it shouldn't make a difference, is unnecessary. I've
applied a slightly modified version of this patch. Specifically I moved
this code to the tail of the tegra_pcie_phy_power_on() function, which
is closest to where it was before.

I've also applied the patch that changes the values that are written
into this register, though I reversed the order because that made more
sense to me. I've pushed both patches to the for-4.8/pci branch in the
Tegra tree, can you please take a look if that still looks okay to you?

Thierry
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20160630/a8b7fa3d/attachment-0001.sig>
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help