[U-Boot] [PATCH] Powerpc: Make pcie link state judge more specific

[York Sun]

On 09/24/2017 08:44 PM, Bao Xiaowei wrote:
> For some special reset times for longer pcie devices, in this case, the
> pcie device may on polling compliance state, the RC considers the pcie
> device is link up, but the pcie device is not link up, only the L0 state
> is link up state. So add the link up status judgement mechanisms.
> 
> Signed-off-by: Bao Xiaowei <xiaowei.bao at nxp.com>
> ---
> v2:
>  - Detailed function module
>  - Adjust the code structure

Mingkai,

Please ack if you agree with this change.

Xiaowei,

Please see some inline comments.

> 
>  arch/powerpc/include/asm/fsl_pci.h |   3 +
>  drivers/pci/fsl_pci_init.c         | 151 ++++++++++++++++++++-----------------
>  2 files changed, 86 insertions(+), 68 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/fsl_pci.h b/arch/powerpc/include/asm/fsl_pci.h
> index cad341e..9dfbf19 100644
> --- a/arch/powerpc/include/asm/fsl_pci.h
> +++ b/arch/powerpc/include/asm/fsl_pci.h
> @@ -24,6 +24,9 @@
>  
>  #define PCI_LTSSM	0x404   /* PCIe Link Training, Status State Machine */
>  #define  PCI_LTSSM_L0	0x16    /* L0 state */
> +#define PCIE_GEN3_LTSSM_L0     0x11    /* L0 state */
> +#define LTSSM_PCIE_DETECT_QUIET                0x00 /* Detect state */
> +#define LTSSM_PCIE_DETECT_ACTIVE       0x01 /* Detect state */
>  
>  int fsl_setup_hose(struct pci_controller *hose, unsigned long addr);
>  int fsl_is_pci_agent(struct pci_controller *hose);
> diff --git a/drivers/pci/fsl_pci_init.c b/drivers/pci/fsl_pci_init.c
> index af20cf0..5d697bc 100644
> --- a/drivers/pci/fsl_pci_init.c
> +++ b/drivers/pci/fsl_pci_init.c
> @@ -39,6 +39,8 @@ DECLARE_GLOBAL_DATA_PTR;
>  #if defined(CONFIG_SYS_PCI_64BIT) && !defined(CONFIG_SYS_PCI64_MEMORY_BUS)
>  #define CONFIG_SYS_PCI64_MEMORY_BUS (64ull*1024*1024*1024)
>  #endif
> +#define PEX_CSR0_LTSSM_MASK	0xFC
> +#define PEX_CSR0_LTSSM_SHIFT	2
>  
>  /* Setup one inbound ATMU window.
>   *
> @@ -290,6 +292,81 @@ static void fsl_pcie_boot_master_release_slave(int port)
>  }
>  #endif
>  
> +static int is_pcie_gen3(struct fsl_pci_info *pci_info)
> +{
> +	u32 cfg_addr = (u32)&((ccsr_fsl_pci_t *)pci_info->regs)->cfg_addr;
> +	volatile ccsr_fsl_pci_t *pci = (ccsr_fsl_pci_t *)cfg_addr;
> +	u32 block_rev;
> +
> +	block_rev = in_be32(&pci->block_rev1);
> +	if (block_rev >= PEX_IP_BLK_REV_3_0)
> +		return 1;
> +	else

You don't need the "else" here.

> +		return 0;
> +}
> +
> +static int get_ltssm_val(struct pci_controller *hose,
> +			 struct fsl_pci_info *pci_info)
> +{
> +	u16 ltssm = 0;
> +	pci_dev_t dev = PCI_BDF(hose->first_busno, 0, 0);
> +	u32 cfg_addr = (u32)&((ccsr_fsl_pci_t *)pci_info->regs)->cfg_addr;
> +	volatile ccsr_fsl_pci_t *pci = (ccsr_fsl_pci_t *)cfg_addr;
> +
> +	if (is_pcie_gen3(pci_info))
> +		ltssm = (in_be32(&pci->pex_csr0)
> +			& PEX_CSR0_LTSSM_MASK) >> PEX_CSR0_LTSSM_SHIFT;
> +	else
> +		pci_hose_read_config_word(hose, dev, PCI_LTSSM, &ltssm);
> +
> +	return ltssm;
> +}
> +
> +static int pci_link_up(struct pci_controller *hose,
> +			struct fsl_pci_info *pci_info)
> +{
> +	int enabled = 0;
> +	u16 ltssm;
> +	int i, pcie_ltssm_l0;
> +
> +	if (is_pcie_gen3(pci_info))
> +		pcie_ltssm_l0 = PCIE_GEN3_LTSSM_L0;
> +	else
> +		pcie_ltssm_l0 = PCI_LTSSM_L0;
> +
> +	ltssm = get_ltssm_val(hose, pci_info);
> +	if (ltssm == LTSSM_PCIE_DETECT_QUIET ||
> +		ltssm == LTSSM_PCIE_DETECT_ACTIVE)
> +		enabled = 0;
> +	else if (ltssm == PCIE_GEN3_LTSSM_L0)
> +		enabled = 1;
> +	else {
> +		for (i = 0; i < 100 && ltssm != pcie_ltssm_l0; i++) {
> +			ltssm = get_ltssm_val(hose, pci_info);
> +			udelay(1000);
> +		}
> +		enabled = (ltssm == pcie_ltssm_l0) ? 1 : 0;
> +	}
> +	return enabled;

Add blank line above "return".

> +}

You don't have to send an update unless you have something else to fix.
I can make cosmetic fix when I merge it.

York