Re: [PATCH V4 2/2] PCI: rcar: Recalculate inbound range alignment for each controller entry

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Mon, Oct 28, 2019 at 08:35:32AM +0000, Yoshihiro Shimoda wrote:
> Hi Marek-san.
> 
> > From: Marek Vasut, Sent: Sunday, October 27, 2019 3:27 AM
> > 
> > Due to hardware constraints, the size of each inbound range entry
> > populated into the controller cannot be larger than the alignment
> > of the entry's start address. Currently, the alignment for each
> > "dma-ranges" inbound range is calculated only once for each range
> > and the increment for programming the controller is also derived
> > from it only once. Thus, a "dma-ranges" entry describing a memory
> > at 0x48000000 and size 0x38000000 would lead to multiple controller
> > entries, each 0x08000000 long.
> 
> I added a debug code [1] and I confirmed that each entry is not 0x08000000 long [2].
> 
> After fixed the commit log above,

So what does this mean in practice ? Does it mean that the commit log is
wrong or that the issue is not present as described, in the mainline
code ?

Please clarify and send a v5 accordingly.

Thanks,
Lorenzo

> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> 
> And I tested on r8a7795-salvator-xs with my debug code. So,
> 
> Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> 
> Best regards,
> Yoshihiro Shimoda
> 
> ---
> [1] Based on next-20191025 with this patch series:
> diff --git a/arch/arm64/boot/dts/renesas/r8a7795.dtsi b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> index fde6ec1..9bdd39e 100644
> --- a/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r8a7795.dtsi
> @@ -2684,7 +2684,7 @@
>  				0x02000000 0 0x30000000 0 0x30000000 0 0x08000000
>  				0x42000000 0 0x38000000 0 0x38000000 0 0x08000000>;
>  			/* Map all possible DDR as inbound ranges */
> -			dma-ranges = <0x42000000 0 0x40000000 0 0x40000000 0 0x40000000>;
> +			dma-ranges = <0x42000000 0 0x48000000 0 0x48000000 0 0x38000000>;
>  			interrupts = <GIC_SPI 116 IRQ_TYPE_LEVEL_HIGH>,
>  				<GIC_SPI 117 IRQ_TYPE_LEVEL_HIGH>,
>  				<GIC_SPI 118 IRQ_TYPE_LEVEL_HIGH>;
> diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
> index 0dadccb..54ad977 100644
> --- a/drivers/pci/controller/pcie-rcar.c
> +++ b/drivers/pci/controller/pcie-rcar.c
> @@ -11,6 +11,8 @@
>   * Author: Phil Edworthy <phil.edworthy@renesas.com>
>   */
>  
> +#define DEBUG
> +
>  #include <linux/bitops.h>
>  #include <linux/clk.h>
>  #include <linux/delay.h>
> @@ -1054,6 +1056,8 @@ static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
>  		mask = roundup_pow_of_two(size) - 1;
>  		mask &= ~0xf;
>  
> +		dev_dbg(pcie->dev, "idx%d: 0x%016llx..0x%016llx -> 0x%016llx\n",
> +			idx, cpu_addr, size, pci_addr);
>  		/*
>  		 * Set up 64-bit inbound regions as the range parser doesn't
>  		 * distinguish between 32 and 64-bit types.
> ---
> [2]
> [    0.374771] rcar-pcie fe000000.pcie: idx0: 0x0000000048000000..0x0000000008000000 -> 0x0000000048000000
> [    0.374777] rcar-pcie fe000000.pcie: idx2: 0x0000000050000000..0x0000000010000000 -> 0x0000000050000000
> [    0.374782] rcar-pcie fe000000.pcie: idx4: 0x0000000060000000..0x0000000020000000 -> 0x0000000060000000
> ---
>