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arm: a37xx: pci: Do not try to access other buses when link is down

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If a PIO request is executed while link-down, the whole controller gets
stuck in a non-functional state, and even after link comes up again, PIO
requests won't work anymore, and a reset of the whole PCIe controller is
needed. Therefore we need to prevent sending PIO requests while the link
is down.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
This commit is contained in:
Pali Rohár 2022-02-15 11:23:35 +01:00 committed by Stefan Roese
parent 0934dddc64
commit 2727e9dd27
1 changed files with 21 additions and 17 deletions
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38
drivers/pci/pci-aardvark.c
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@ -177,6 +177,23 @@ static inline uint advk_readl(struct pcie_advk *pcie, uint reg)
return readl(pcie->base + reg);
}
/**
* pcie_advk_link_up() - Check if PCIe link is up or not
*
* @pcie: The PCI device to access
*
* Return true on link up.
* Return false on link down.
*/
static bool pcie_advk_link_up(struct pcie_advk *pcie)
{
u32 val, ltssm_state;
val = advk_readl(pcie, ADVK_LMI_PHY_CFG0);
ltssm_state = (val & ADVK_LMI_PHY_CFG0_LTSSM_MASK) >> ADVK_LMI_PHY_CFG0_LTSSM_SHIFT;
return ltssm_state >= ADVK_LMI_PHY_CFG0_LTSSM_L0 && ltssm_state < ADVK_LMI_PHY_CFG0_LTSSM_DISABLED;
}
/**
* pcie_advk_addr_valid() - Check for valid bus address
*
@ -195,6 +212,10 @@ static bool pcie_advk_addr_valid(struct pcie_advk *pcie,
if (busno == 0 && (dev != 0 || func != 0))
return false;
/* Access to other buses is possible when link is up */
if (busno != 0 && !pcie_advk_link_up(pcie))
return false;
/*
* In PCI-E only a single device (0) can exist on the secondary bus.
* Beyond the secondary bus, there might be a Switch and anything is
@ -618,23 +639,6 @@ retry:
return ret;
}
/**
* pcie_advk_link_up() - Check if PCIe link is up or not
*
* @pcie: The PCI device to access
*
* Return 1 (true) on link up.
* Return 0 (false) on link down.
*/
static int pcie_advk_link_up(struct pcie_advk *pcie)
{
u32 val, ltssm_state;
val = advk_readl(pcie, ADVK_LMI_PHY_CFG0);
ltssm_state = (val & ADVK_LMI_PHY_CFG0_LTSSM_MASK) >> ADVK_LMI_PHY_CFG0_LTSSM_SHIFT;
return ltssm_state >= ADVK_LMI_PHY_CFG0_LTSSM_L0 && ltssm_state < ADVK_LMI_PHY_CFG0_LTSSM_DISABLED;
}
/**
* pcie_advk_wait_for_link() - Wait for link training to be accomplished
*