Re: [PATCH V2 2/2] PCI: brcmstb: support BCM4908 with external PERST# signal controller

[Rafał Miłecki <rafal@xxxxxxxxxx>]

On 04.12.2020 19:21, Florian Fainelli wrote:
> On 11/30/2020 12:32 AM, Rafał Miłecki wrote:
> > From: Rafał Miłecki <rafal@xxxxxxxxxx>
> >
> > BCM4908 uses external MISC block for controlling PERST# signal. Use it
> > as a reset controller.
> >
> > Signed-off-by: Rafał Miłecki <rafal@xxxxxxxxxx>
> > ---
> > V2: Reorder BCM4908 in the enum pcie_type
> >      Use devm_reset_control_get_optional_exclusive()
> >      Don't move hw_rev read up in the code
> > ---
> >   drivers/pci/controller/Kconfig        |  2 +-
> >   drivers/pci/controller/pcie-brcmstb.c | 32 +++++++++++++++++++++++++++
> >   2 files changed, 33 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> > index 64e2f5e379aa..d44c70bb88f6 100644
> > --- a/drivers/pci/controller/Kconfig
> > +++ b/drivers/pci/controller/Kconfig
> > @@ -273,7 +273,7 @@ config VMD
> >   
> >   config PCIE_BRCMSTB
> >   	tristate "Broadcom Brcmstb PCIe host controller"
> > -	depends on ARCH_BRCMSTB || ARCH_BCM2835 || COMPILE_TEST
> > +	depends on ARCH_BRCMSTB || ARCH_BCM2835 || ARCH_BCM4908 || COMPILE_TEST
> >   	depends on OF
> >   	depends on PCI_MSI_IRQ_DOMAIN
> >   	default ARCH_BRCMSTB
> > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> > index 9c3d2982248d..98536cf3af58 100644
> > --- a/drivers/pci/controller/pcie-brcmstb.c
> > +++ b/drivers/pci/controller/pcie-brcmstb.c
> > @@ -96,6 +96,7 @@
> >   
> >   #define PCIE_MISC_REVISION				0x406c
> >   #define  BRCM_PCIE_HW_REV_33				0x0303
> > +#define  BRCM_PCIE_HW_REV_3_20				0x0320
> >   
> >   #define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT		0x4070
> >   #define  PCIE_MISC_CPU_2_PCIE_MEM_WIN0_BASE_LIMIT_LIMIT_MASK	0xfff00000
> > @@ -190,6 +191,7 @@
> >   struct brcm_pcie;
> >   static inline void brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32 val);
> >   static inline void brcm_pcie_bridge_sw_init_set_generic(struct brcm_pcie *pcie, u32 val);
> > +static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val);
> >   static inline void brcm_pcie_perst_set_7278(struct brcm_pcie *pcie, u32 val);
> >   static inline void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val);
> >   
> > @@ -206,6 +208,7 @@ enum {
> >   
> >   enum pcie_type {
> >   	GENERIC,
> > +	BCM4908,
> >   	BCM7278,
> >   	BCM2711,
> >   };
> > @@ -230,6 +233,13 @@ static const struct pcie_cfg_data generic_cfg = {
> >   	.bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
> >   };
> >   
> > +static const struct pcie_cfg_data bcm4908_cfg = {
> > +	.offsets	= pcie_offsets,
> > +	.type		= BCM4908,
> > +	.perst_set	= brcm_pcie_perst_set_4908,
> > +	.bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
> > +};
> > +
> >   static const int pcie_offset_bcm7278[] = {
> >   	[RGR1_SW_INIT_1] = 0xc010,
> >   	[EXT_CFG_INDEX] = 0x9000,
> > @@ -282,6 +292,7 @@ struct brcm_pcie {
> >   	const int		*reg_offsets;
> >   	enum pcie_type		type;
> >   	struct reset_control	*rescal;
> > +	struct reset_control	*perst_reset;
> >   	int			num_memc;
> >   	u64			memc_size[PCIE_BRCM_MAX_MEMC];
> >   	u32			hw_rev;
> > @@ -747,6 +758,17 @@ static inline void brcm_pcie_bridge_sw_init_set_7278(struct brcm_pcie *pcie, u32
> >   	writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
> >   }
> >   
> > +static inline void brcm_pcie_perst_set_4908(struct brcm_pcie *pcie, u32 val)
> > +{
> > +	if (WARN_ONCE(!pcie->perst_reset, "missing PERST# reset controller\n"))
> > +		return;
> > +
> > +	if (val)
> > +		reset_control_assert(pcie->perst_reset);
> > +	else
> > +		reset_control_deassert(pcie->perst_reset);
>
> This looks good to me now, just one nit, you probably do not support
> suspend/resume on the 4908, likely never will, but you should probably
> pulse the PERST# during PCIe resume, too. With that fixed:
>
> Acked-by: Florian Fainelli <f.fainelli@xxxxxxxxx>

Driver already does that.

Suspend forward trace:
brcm_pcie_suspend()
brcm_pcie_turn_off()
pcie->perst_set(pcie, 1)

Resume forward trace:
brcm_pcie_resume()
brcm_pcie_setup()
pcie->perst_set(pcie, 0)

Correct me if I'm wrong please.