On Thu, Aug 10, 2023 at 05:50:02PM +0530, Thippeswamy Havalige wrote:
> Our controller is expecting ECAM size to be programmed by software. By
> programming "NWL_ECAM_VALUE_DEFAULT 12" controller can access up to 16MB
> ECAM region which is used to detect 16 buses, so by updating
> "NWL_ECAM_VALUE_DEFAULT" to 16 so that controller can access up to 256MB
> ECAM region to detect 256 buses.
What happens when your DT has the smaller size and the kernel configures
the larger size? Seems like you could have an ABI issue.
>
> Signed-off-by: Thippeswamy Havalige <thippeswamy.havalige@xxxxxxx>
> Signed-off-by: Bharat Kumar Gogada <bharat.kumar.gogada@xxxxxxx>
> ---
> changes in v3:
> - Remove unnecessary period at end of subject line.
> changes in v2:
> - Update this changes in a seperate patch.
> ---
> drivers/pci/controller/pcie-xilinx-nwl.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-xilinx-nwl.c b/drivers/pci/controller/pcie-xilinx-nwl.c
> index d8a3a08be1d5..b51501921d3b 100644
> --- a/drivers/pci/controller/pcie-xilinx-nwl.c
> +++ b/drivers/pci/controller/pcie-xilinx-nwl.c
> @@ -126,7 +126,7 @@
> #define E_ECAM_CR_ENABLE BIT(0)
> #define E_ECAM_SIZE_LOC GENMASK(20, 16)
> #define E_ECAM_SIZE_SHIFT 16
> -#define NWL_ECAM_VALUE_DEFAULT 12
> +#define NWL_ECAM_VALUE_DEFAULT 16
Not really a meaningful name. It doesn't explain what '16' means.
> #define CFG_DMA_REG_BAR GENMASK(2, 0)
> #define CFG_PCIE_CACHE GENMASK(7, 0)
> @@ -165,7 +165,6 @@ struct nwl_pcie {
> u32 ecam_size;
> int irq_intx;
> int irq_misc;
> - u32 ecam_value;
> struct nwl_msi msi;
> struct irq_domain *legacy_irq_domain;
> struct clk *clk;
> @@ -674,7 +673,7 @@ static int nwl_pcie_bridge_init(struct nwl_pcie *pcie)
> E_ECAM_CR_ENABLE, E_ECAM_CONTROL);
>
> nwl_bridge_writel(pcie, nwl_bridge_readl(pcie, E_ECAM_CONTROL) |
> - (pcie->ecam_value << E_ECAM_SIZE_SHIFT),
> + (NWL_ECAM_VALUE_DEFAULT << E_ECAM_SIZE_SHIFT),
> E_ECAM_CONTROL);
>
> nwl_bridge_writel(pcie, lower_32_bits(pcie->phys_ecam_base),
> @@ -782,7 +781,6 @@ static int nwl_pcie_probe(struct platform_device *pdev)
> pcie = pci_host_bridge_priv(bridge);
>
> pcie->dev = dev;
> - pcie->ecam_value = NWL_ECAM_VALUE_DEFAULT;
>
> err = nwl_pcie_parse_dt(pcie, pdev);
> if (err) {
> --
> 2.17.1
>
