Re: [PATCH v4 2/5] pci:host: Add Altera PCIe host controller driver

From: Dinh Nguyen <dinh.linux@gmail.com>
To: Ley Foon Tan <lftan@altera.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Russell King <linux@arm.linux.org.uk>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Ley Foon Tan <lftan.linux@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	linux-pci@vger.kernel.org,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Linux List <linux-kernel@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
	Kumar Gala <galak@codeaurora.org>,
	Dinh Nguyen <dinguyen@opensource.altera.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 2/5] pci:host: Add Altera PCIe host controller driver
Date: Tue, 18 Aug 2015 14:11:58 -0500	[thread overview]
Message-ID: <CADhT+wfjYaEefScKNz-R5miA+_Ybm8PTHgG6jDT9ntb9e89twQ@mail.gmail.com> (raw)
In-Reply-To: <1439802579-22651-3-git-send-email-lftan@altera.com>

On Mon, Aug 17, 2015 at 4:09 AM, Ley Foon Tan <lftan@altera.com> wrote:
> This patch adds the Altera PCIe host controller driver.
>
> Signed-off-by: Ley Foon Tan <lftan@altera.com>
> ---
>  drivers/pci/host/Kconfig       |   7 +
>  drivers/pci/host/Makefile      |   1 +
>  drivers/pci/host/pcie-altera.c | 543 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 551 insertions(+)
>  create mode 100644 drivers/pci/host/pcie-altera.c
>
> diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
> index 675c2d1..4b4754a 100644
> --- a/drivers/pci/host/Kconfig
> +++ b/drivers/pci/host/Kconfig
> @@ -145,4 +145,11 @@ config PCIE_IPROC_BCMA
>           Say Y here if you want to use the Broadcom iProc PCIe controller
>           through the BCMA bus interface
>

<snip>

> +
> +/* Address translation table entry size */
> +#define ATT_ENTRY_SIZE         8
> +
> +#define DWORD_MASK             3
> +
> +struct altera_pcie {
> +       struct platform_device  *pdev;
> +       struct resource         *txs;

You have "Txs" documented in the bindings document, you have a pointer
here, but you've never used it
anywhre in the code? What is it for?

> +       void __iomem            *cra_base;
> +       int                     irq;
> +       u8                      root_bus_nr;
> +       struct irq_domain               *irq_domain;
> +       struct resource         bus_range;
> +       struct list_head                resources;
> +};
> +

<snip>

> +
> +static int tlp_cfg_dword_read(struct altera_pcie *pcie, u8 bus, u32 devfn,
> +                             int where, u32 *value)
> +{
> +       int ret;
> +       u32 headers[TLP_HDR_SIZE];
> +
> +       if (bus == pcie->root_bus_nr)
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD0);
> +       else
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGRD1);
> +
> +       headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> +                                       TLP_READ_TAG);
> +       headers[2] = TLP_CFG_DW2(bus, devfn, where);
> +
> +       tlp_write_packet(pcie, headers, 0);
> +
> +       ret = tlp_read_packet(pcie, value);
> +       if (ret)
> +               *value = ~0UL;  /* return 0xFFFFFFFF if error */
> +
> +       return ret;
> +}
> +
> +static int tlp_cfg_dword_write(struct altera_pcie *pcie, u8 bus, u32 devfn,
> +                              int where, u32 value)
> +{
> +       u32 headers[TLP_HDR_SIZE];
> +
> +       if (bus == pcie->root_bus_nr)
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR0);
> +       else
> +               headers[0] = TLP_CFG_DW0(TLP_FMTTYPE_CFGWR1);
> +
> +       headers[1] = TLP_CFG_DW1(TLP_REQ_ID(pcie->root_bus_nr, devfn),
> +                                       TLP_WRITE_TAG);
> +       headers[2] = TLP_CFG_DW2(bus, devfn, where);
> +
> +       tlp_write_packet(pcie, headers, value);
> +
> +       tlp_read_packet(pcie, NULL);

You need to check for the error here.

> +
> +       /* Keep an eye out for changes to the root bus number */
> +       if ((bus == pcie->root_bus_nr) && (where == PCI_PRIMARY_BUS))
> +               pcie->root_bus_nr = (u8)(value);
> +
> +       return PCIBIOS_SUCCESSFUL;
> +}
> +

<snip>

> +
> +static int altera_pcie_parse_dt(struct altera_pcie *pcie)
> +{
> +       struct resource *cra;
> +       struct platform_device *pdev = pcie->pdev;
> +
> +       cra = platform_get_resource_byname(pdev, IORESOURCE_MEM, "Cra");
> +       if (!cra) {
> +               cra = platform_get_resource_byname(pdev, IORESOURCE_MEM, "cra");
> +               if (!cra) {
> +                       dev_err(&pdev->dev,
> +                               "no cra memory resource defined\n");
> +                       return -ENODEV;
> +               }
> +       }
> +

What about "Txs"?

Dinh