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PCI: iproc: Improve link detection logic 

Improve the link detection logic by explicitly querying the link status
register to ensure link is active.

Also force class to PCI_CLASS_BRIDGE_PCI (0x0604) through the host
configuration space register.

Signed-off-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
This commit is contained in:
Ray Jui 2015-09-15 17:39:19 -07:00 committed by Bjorn Helgaas
parent 199ff14100
commit aaf22ab4e9
1 changed files with 23 additions and 6 deletions
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29
drivers/pci/host/pcie-iproc.c
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@ -60,6 +60,12 @@
#define SYS_RC_INTX_EN 0x330
#define SYS_RC_INTX_MASK 0xf
#define PCIE_LINK_STATUS_OFFSET 0xf0c
#define PCIE_PHYLINKUP_SHIFT 3
#define PCIE_PHYLINKUP BIT(PCIE_PHYLINKUP_SHIFT)
#define PCIE_DL_ACTIVE_SHIFT 2
#define PCIE_DL_ACTIVE BIT(PCIE_DL_ACTIVE_SHIFT)
static inline struct iproc_pcie *iproc_data(struct pci_bus *bus)
{
struct iproc_pcie *pcie;
@ -138,9 +144,15 @@ static void iproc_pcie_reset(struct iproc_pcie *pcie)
static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus)
{
u8 hdr_type;
u32 link_ctrl;
u32 link_ctrl, class, val;
u16 pos, link_status;
int link_is_active = 0;
bool link_is_active = false;
val = readl(pcie->base + PCIE_LINK_STATUS_OFFSET);
if (!(val & PCIE_PHYLINKUP) || !(val & PCIE_DL_ACTIVE)) {
dev_err(pcie->dev, "PHY or data link is INACTIVE!\n");
return -ENODEV;
}
/* make sure we are not in EP mode */
pci_bus_read_config_byte(bus, 0, PCI_HEADER_TYPE, &hdr_type);
@ -150,14 +162,19 @@ static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus)
}
/* force class to PCI_CLASS_BRIDGE_PCI (0x0604) */
pci_bus_write_config_word(bus, 0, PCI_CLASS_DEVICE,
PCI_CLASS_BRIDGE_PCI);
#define PCI_BRIDGE_CTRL_REG_OFFSET 0x43c
#define PCI_CLASS_BRIDGE_MASK 0xffff00
#define PCI_CLASS_BRIDGE_SHIFT 8
pci_bus_read_config_dword(bus, 0, PCI_BRIDGE_CTRL_REG_OFFSET, &class);
class &= ~PCI_CLASS_BRIDGE_MASK;
class |= (PCI_CLASS_BRIDGE_PCI << PCI_CLASS_BRIDGE_SHIFT);
pci_bus_write_config_dword(bus, 0, PCI_BRIDGE_CTRL_REG_OFFSET, class);
/* check link status to see if link is active */
pos = pci_bus_find_capability(bus, 0, PCI_CAP_ID_EXP);
pci_bus_read_config_word(bus, 0, pos + PCI_EXP_LNKSTA, &link_status);
if (link_status & PCI_EXP_LNKSTA_NLW)
link_is_active = 1;
link_is_active = true;
if (!link_is_active) {
/* try GEN 1 link speed */
@ -181,7 +198,7 @@ static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus)
pci_bus_read_config_word(bus, 0, pos + PCI_EXP_LNKSTA,
&link_status);
if (link_status & PCI_EXP_LNKSTA_NLW)
link_is_active = 1;
link_is_active = true;
}
}