Re: [PATCH v2 2/2] PCI: mediatek-gen3: Configure PBUS_CSR registers for EN7581 SoC

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On Sun, Feb 02, 2025 at 08:34:24PM +0100, Lorenzo Bianconi wrote:
> > Configure PBus base address and address mask to allow the hw
> > to detect if a given address is on PCIE0, PCIE1 or PCIE2.
> > 
> > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > ---
> >  drivers/pci/controller/pcie-mediatek-gen3.c | 30 ++++++++++++++++++++++++++++-
> >  1 file changed, 29 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pci/controller/pcie-mediatek-gen3.c b/drivers/pci/controller/pcie-mediatek-gen3.c
> > index aa24ac9aaecc749b53cfc4faf6399913d20cdbf2..9c2a592cae959de8fbe9ca5c5c2253f8eadf2c76 100644
> > --- a/drivers/pci/controller/pcie-mediatek-gen3.c
> > +++ b/drivers/pci/controller/pcie-mediatek-gen3.c
> > @@ -15,6 +15,7 @@
> >  #include <linux/irqchip/chained_irq.h>
> >  #include <linux/irqdomain.h>
> >  #include <linux/kernel.h>
> > +#include <linux/mfd/syscon.h>
> >  #include <linux/module.h>
> >  #include <linux/msi.h>
> >  #include <linux/of_device.h>
> > @@ -24,6 +25,7 @@
> >  #include <linux/platform_device.h>
> >  #include <linux/pm_domain.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/regmap.h>
> >  #include <linux/reset.h>
> >  
> >  #include "../pci.h"
> > @@ -127,6 +129,13 @@
> >  
> >  #define PCIE_MTK_RESET_TIME_US		10
> >  
> > +#define PCIE_EN7581_PBUS_ADDR(_n)	(0x00 + ((_n) << 3))
> > +#define PCIE_EN7581_PBUS_ADDR_MASK(_n)	(0x04 + ((_n) << 3))
> > +#define PCIE_EN7581_PBUS_BASE_ADDR(_n)	\
> > +	((_n) == 2 ? 0x28000000 :	\
> > +	 (_n) == 1 ? 0x24000000 : 0x20000000)
> > +#define PCIE_EN7581_PBUS_BASE_ADDR_MASK	GENMASK(31, 26)
> > +
> >  /* Time in ms needed to complete PCIe reset on EN7581 SoC */
> >  #define PCIE_EN7581_RESET_TIME_MS	100
> >  
> > @@ -931,7 +940,8 @@ static int mtk_pcie_parse_port(struct mtk_gen3_pcie *pcie)
> >  static int mtk_pcie_en7581_power_up(struct mtk_gen3_pcie *pcie)
> >  {
> >  	struct device *dev = pcie->dev;
> > -	int err;
> > +	struct regmap *map;
> > +	int err, slot;
> >  	u32 val;
> >  
> >  	/*
> > @@ -945,6 +955,24 @@ static int mtk_pcie_en7581_power_up(struct mtk_gen3_pcie *pcie)
> >  	/* Wait for the time needed to complete the reset lines assert. */
> >  	msleep(PCIE_EN7581_RESET_TIME_MS);
> >  
> > +	map = syscon_regmap_lookup_by_phandle(dev->of_node,
> > +					      "mediatek,pbus-csr");
> > +	if (IS_ERR(map))
> > +		return PTR_ERR(map);
> 
> So this is going to regress the devicetree's that do not define this syscon
> region? But I do not see any devicetree using this 'airoha,en7581-pcie'
> compatible, so not sure if this is going to be an issue. Are the downstream
> devicetrees used?

AFAIK there is no upstream or downstream (e.g. OpenWrt) en7581 dts with PCIe
support yet so I do not know if this is an issue or not. If so, I guess we
need to add the proper Fixes tag:

Fixes: f6ab898356dd ("PCI: mediatek-gen3: Add Airoha EN7581 support")

Regards,
Lorenzo

> 
> - Mani
> 
> -- 
> மணிவண்ணன் சதாசிவம்

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