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PCI: altera: Poll for link training status after retraining the link

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Poll for link training status is cleared before poll for link up status.
This can help to get the reliable link up status, especially when PCIe is
in Gen 3 speed.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Ley Foon Tan 2016-08-15 14:06:02 +08:00 committed by Bjorn Helgaas
parent 29b4817d40
commit 411dc32d88
1 changed files with 37 additions and 8 deletions
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45
drivers/pci/host/pcie-altera.c
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@ -61,7 +61,8 @@
#define TLP_LOOP 500
#define RP_DEVFN 0
#define LINK_UP_TIMEOUT 5000
#define LINK_UP_TIMEOUT HZ
#define LINK_RETRAIN_TIMEOUT HZ
#define INTX_NUM 4
@ -99,11 +100,44 @@ static bool altera_pcie_link_is_up(struct altera_pcie *pcie)
return !!((cra_readl(pcie, RP_LTSSM) & RP_LTSSM_MASK) == LTSSM_L0);
}
static void altera_wait_link_retrain(struct pci_dev *dev)
{
u16 reg16;
unsigned long start_jiffies;
struct altera_pcie *pcie = dev->bus->sysdata;
/* Wait for link training end. */
start_jiffies = jiffies;
for (;;) {
pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_LT))
break;
if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT)) {
dev_err(&pcie->pdev->dev, "link retrain timeout\n");
break;
}
udelay(100);
}
/* Wait for link is up */
start_jiffies = jiffies;
for (;;) {
if (altera_pcie_link_is_up(pcie))
break;
if (time_after(jiffies, start_jiffies + LINK_UP_TIMEOUT)) {
dev_err(&pcie->pdev->dev, "link up timeout\n");
break;
}
udelay(100);
}
}
static void altera_pcie_retrain(struct pci_dev *dev)
{
u16 linkcap, linkstat;
struct altera_pcie *pcie = dev->bus->sysdata;
int timeout = 0;
if (!altera_pcie_link_is_up(pcie))
return;
@ -121,12 +155,7 @@ static void altera_pcie_retrain(struct pci_dev *dev)
if ((linkstat & PCI_EXP_LNKSTA_CLS) == PCI_EXP_LNKSTA_CLS_2_5GB) {
pcie_capability_set_word(dev, PCI_EXP_LNKCTL,
PCI_EXP_LNKCTL_RL);
while (!altera_pcie_link_is_up(pcie)) {
timeout++;
if (timeout > LINK_UP_TIMEOUT)
break;
udelay(5);
}
altera_wait_link_retrain(dev);
}
}
DECLARE_PCI_FIXUP_EARLY(0x1172, PCI_ANY_ID, altera_pcie_retrain);