Date:   Mon, 17 Dec 2018 16:19:39 +0800
From:   Jianjun Wang <jianjun.wang@...iatek.com>
To:     Bjorn Helgaas <helgaas@...nel.org>
CC:     <ryder.lee@...iatek.com>, <robh+dt@...nel.org>,
        <lorenzo.pieralisi@....com>, <matthias.bgg@...il.com>,
        <linux-pci@...r.kernel.org>, <mark.rutland@....com>,
        <devicetree@...r.kernel.org>, <youlin.pei@...iatek.com>,
        <linux-kernel@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <honghui.zhang@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 2/2] PCI: mediatek: Add controller support for MT7629

On Thu, 2018-12-13 at 08:55 -0600, Bjorn Helgaas wrote:
> On Thu, Dec 06, 2018 at 09:09:13AM +0800, Jianjun Wang wrote:
> > MT7629 is an arm platform SoC which has the same PCIe IP with MT7622.
> 
> s/arm/ARM/
> 
> > The read value of BAR0 is 0xffff_ffff, it's size will be calculated as 4GB
> > in arm64 but bogus alignment values at arm32, the pcie device and devices
> > behind this bridge will not be enabled. Fix it's BAR0 resource size to
> > guarantee the pcie devices will be enabled correctly.
> 
> So this is a hardware erratum?  Per spec, a memory BAR has bit 0 hardwired
> to 0, and an IO BAR has bit 1 hardwired to 0.

Yes, it only works properly on 64bit platform.
> 
> > The HW default value of its device id is invalid, fix it's device id to
> > match the hardware implementation.
> 
> s/pcie/PCIe/ (all places above)
> s/it's/its/ (all places above)
> s/device id/Device ID/

OK, thanks.
> 
> > Signed-off-by: Jianjun Wang <jianjun.wang@...iatek.com>
> > ---
> >  drivers/pci/controller/pcie-mediatek.c | 26 ++++++++++++++++++++++++++
> >  include/linux/pci_ids.h                |  1 +
> >  2 files changed, 27 insertions(+)
> > 
> > diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> > index d20cf461ba00..f8937cc3c87c 100644
> > --- a/drivers/pci/controller/pcie-mediatek.c
> > +++ b/drivers/pci/controller/pcie-mediatek.c
> > @@ -73,6 +73,7 @@
> >  #define PCIE_MSI_VECTOR		0x0c0
> >  
> >  #define PCIE_CONF_VEND_ID	0x100
> > +#define PCIE_CONF_DEVICE_ID	0x102
> >  #define PCIE_CONF_CLASS_ID	0x106
> >  
> >  #define PCIE_INT_MASK		0x420
> > @@ -135,12 +136,14 @@ struct mtk_pcie_port;
> >  /**
> >   * struct mtk_pcie_soc - differentiate between host generations
> >   * @need_fix_class_id: whether this host's class ID needed to be fixed or not
> > + * @need_fix_device_id: whether this host's device ID needed to be fixed or not
> >   * @ops: pointer to configuration access functions
> >   * @startup: pointer to controller setting functions
> >   * @setup_irq: pointer to initialize IRQ functions
> >   */
> >  struct mtk_pcie_soc {
> >  	bool need_fix_class_id;
> > +	bool need_fix_device_id;
> >  	struct pci_ops *ops;
> >  	int (*startup)(struct mtk_pcie_port *port);
> >  	int (*setup_irq)(struct mtk_pcie_port *port, struct device_node *node);
> > @@ -692,6 +695,11 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
> >  		writew(val, port->base + PCIE_CONF_CLASS_ID);
> >  	}
> >  
> > +	if (soc->need_fix_device_id) {
> > +		val = PCI_DEVICE_ID_MEDIATEK_7629;
> > +		writew(val, port->base + PCIE_CONF_DEVICE_ID);
> > +	}
> > +
> >  	/* 100ms timeout value should be enough for Gen1/2 training */
> >  	err = readl_poll_timeout(port->base + PCIE_LINK_STATUS_V2, val,
> >  				 !!(val & PCIE_PORT_LINKUP_V2), 20,
> > @@ -1238,11 +1246,29 @@ static const struct mtk_pcie_soc mtk_pcie_soc_mt7622 = {
> >  	.setup_irq = mtk_pcie_setup_irq,
> >  };
> >  
> > +static const struct mtk_pcie_soc mtk_pcie_soc_mt7629 = {
> > +	.need_fix_class_id = true,
> > +	.need_fix_device_id = true,
> > +	.ops = &mtk_pcie_ops_v2,
> > +	.startup = mtk_pcie_startup_port_v2,
> > +	.setup_irq = mtk_pcie_setup_irq,
> > +};
> > +
> > +static void mtk_fixup_bar_size(struct pci_dev *dev)
> > +{
> > +	struct resource *dev_res = &dev->resource[0];
> 
> Add a blank line here.

OK.
> 
> > +	/* 32bit resource length will calculate size to 0, set it smaller */
> > +	dev_res->end = 0xfffffffe;
> 
> Presumably you know the size of the BAR because that's fixed by the
> hardware and documented in the spec.  You should do something like
> this so you don't depend on what the BAR contains, e.g.,
> 
>   res->end = res->start + size - 1;

Yes, it will be much more better, I will modify the code in next
version, thanks.
> 
> > +}
> > +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_MEDIATEK, PCI_DEVICE_ID_MEDIATEK_7629,
> > +			 mtk_fixup_bar_size);
> > +
> >  static const struct of_device_id mtk_pcie_ids[] = {
> >  	{ .compatible = "mediatek,mt2701-pcie", .data = &mtk_pcie_soc_v1 },
> >  	{ .compatible = "mediatek,mt7623-pcie", .data = &mtk_pcie_soc_v1 },
> >  	{ .compatible = "mediatek,mt2712-pcie", .data = &mtk_pcie_soc_mt2712 },
> >  	{ .compatible = "mediatek,mt7622-pcie", .data = &mtk_pcie_soc_mt7622 },
> > +	{ .compatible = "mediatek,mt7629-pcie", .data = &mtk_pcie_soc_mt7629 },
> >  	{},
> >  };
> >  
> > diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
> > index 69f0abe1ba1a..77b278bac3a8 100644
> > --- a/include/linux/pci_ids.h
> > +++ b/include/linux/pci_ids.h
> > @@ -2126,6 +2126,7 @@
> >  #define PCI_VENDOR_ID_MYRICOM		0x14c1
> >  
> >  #define PCI_VENDOR_ID_MEDIATEK		0x14c3
> > +#define PCI_DEVICE_ID_MEDIATEK_7629	0x7629
> >  
> >  #define PCI_VENDOR_ID_TITAN		0x14D2
> >  #define PCI_DEVICE_ID_TITAN_010L	0x8001
> > -- 
> > 2.19.1
> > 
> > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@...ts.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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