Thread (6 messages) flat view 6 messages, 2 authors, 2016-07-21

[PATCH 2/2] PCI: designware: let dw_pcie_link_up() beware of LTSSM training bit

From: Joao Pinto <hidden>
Date: 2016-07-15 15:10:34
Also in: linux-pci, lkml

Hi,

On 7/6/2016 11:59 AM, Jisheng Zhang wrote:
quoted hunk ↗ jump to hunk
The link may be UP but still in link training. In this case, we can't
think the link is up and operating correctly. So we need to teach
dw_pcie_link_up() beware of the PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING bit.

This patch also rewrite PCIE_PHY_DEBUG_R1_LINK_UP definition so that
it's consistent with other MACROS.

Signed-off-by: Jisheng Zhang <redacted>
---
 drivers/pci/host/pcie-designware.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index 9df879a..29e10dd 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -73,7 +73,8 @@
 /* PCIe Port Logic registers */
 #define PLR_OFFSET			0x700
 #define PCIE_PHY_DEBUG_R1		(PLR_OFFSET + 0x2c)
-#define PCIE_PHY_DEBUG_R1_LINK_UP	0x00000010
+#define PCIE_PHY_DEBUG_R1_LINK_UP	(0x1 << 4)
+#define PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING	(0x1 << 29)
According to the databook bit 29 is inside a range that is dedicated to M-PCIe.
Have you checked bit 29 state by experience?
quoted hunk ↗ jump to hunk
 
 /* Parameters for the waiting for link up routine */
 #define LINK_WAIT_MAX_RETRIES		10
@@ -417,7 +418,8 @@ int dw_pcie_link_up(struct pcie_port *pp)
 		return pp->ops->link_up(pp);
 
 	val = readl(pp->dbi_base + PCIE_PHY_DEBUG_R1);
-	return val & PCIE_PHY_DEBUG_R1_LINK_UP;
+	return ((val & PCIE_PHY_DEBUG_R1_LINK_UP) &&
+		(!(val & PCIE_PHY_DEBUG_R1_LINK_IN_TRAINING)));
 }
 
 static int dw_pcie_msi_map(struct irq_domain *domain, unsigned int irq,
Thanks,
Joao
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