Re: [RFC PATCH] PCI: rcar: Fix incorrect programming of OB windows

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

On Fri, Oct 04, 2019 at 02:29:41PM +0100, Andrew Murray wrote:
> The outbound windows (PCIEPAUR(x), PCIEPALR(x)) describe a mapping between
> a CPU address (which is determined by the window number 'x') and a
> programmed PCI address - Thus allowing the controller to translate CPU
> accesses into PCI accesses.
> 
> However the existing code incorrectly writes the CPU address - lets fix
> this by writing the PCI address instead.
> 
> For memory transactions, existing DT users describe a 1:1 identity mapping
> and thus this change should have no effect. However the same isn't true for
> I/O.
> 
> Fixes: c25da4778803 ("PCI: rcar: Add Renesas R-Car PCIe driver")
> Signed-off-by: Andrew Murray <andrew.murray@arm.com>
> 
> ---
> This hasn't been tested, so keen for someone to give it a try.
> 
> Also keen for someone to confirm my understanding that the RCar windows
> expect PCI addresses and that res->start refers to CPU addresses. If this
> is correct then it's possible the I/O doesn't work correctly.
> ---
>  drivers/pci/controller/pcie-rcar.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)

Applied to pci/rcar, thanks !

Lorenzo

> diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
> index f6a669a9af41..b28d726b4aba 100644
> --- a/drivers/pci/controller/pcie-rcar.c
> +++ b/drivers/pci/controller/pcie-rcar.c
> @@ -332,11 +332,12 @@ static struct pci_ops rcar_pcie_ops = {
>  };
>  
>  static void rcar_pcie_setup_window(int win, struct rcar_pcie *pcie,
> -				   struct resource *res)
> +				   struct resource_entry *window)
>  {
>  	/* Setup PCIe address space mappings for each resource */
>  	resource_size_t size;
>  	resource_size_t res_start;
> +	struct resource *res = window->res;
>  	u32 mask;
>  
>  	rcar_pci_write_reg(pcie, 0x00000000, PCIEPTCTLR(win));
> @@ -350,9 +351,9 @@ static void rcar_pcie_setup_window(int win, struct rcar_pcie *pcie,
>  	rcar_pci_write_reg(pcie, mask << 7, PCIEPAMR(win));
>  
>  	if (res->flags & IORESOURCE_IO)
> -		res_start = pci_pio_to_address(res->start);
> +		res_start = pci_pio_to_address(res->start) - window->offset;
>  	else
> -		res_start = res->start;
> +		res_start = res->start - window->offset;
>  
>  	rcar_pci_write_reg(pcie, upper_32_bits(res_start), PCIEPAUR(win));
>  	rcar_pci_write_reg(pcie, lower_32_bits(res_start) & ~0x7F,
> @@ -381,7 +382,7 @@ static int rcar_pcie_setup(struct list_head *resource, struct rcar_pcie *pci)
>  		switch (resource_type(res)) {
>  		case IORESOURCE_IO:
>  		case IORESOURCE_MEM:
> -			rcar_pcie_setup_window(i, pci, res);
> +			rcar_pcie_setup_window(i, pci, win);
>  			i++;
>  			break;
>  		case IORESOURCE_BUS:
> -- 
> 2.21.0
>