On Fri, Jan 31, 2025 at 07:29:51PM +0100, Niklas Cassel wrote:
> Add a helper function to convert a size to the representation used by the
> Resizable BAR Capability Register.
>
> Signed-off-by: Niklas Cassel <cassel@xxxxxxxxxx>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
One nit below.
> ---
> drivers/pci/endpoint/pci-epc-core.c | 27 +++++++++++++++++++++++++++
> include/linux/pci-epc.h | 1 +
> 2 files changed, 28 insertions(+)
>
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 10dfc716328e..5d6aef956b13 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -638,6 +638,33 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> }
> EXPORT_SYMBOL_GPL(pci_epc_set_bar);
>
> +/**
> + * pci_epc_bar_size_to_rebar_cap() - convert a size to the representation used
> + * by the Resizable BAR Capability Register
> + * @size: the size to convert
> + * @cap: where to store the result
> + *
> + * Returns 0 on success and a negative error code in case of error.
> + */
> +int pci_epc_bar_size_to_rebar_cap(size_t size, u32 *cap)
> +{
> + /*
> + * According to PCIe base spec, min size for a resizable BAR is 1 MB,
> + * thus disallow a requested BAR size smaller than 1 MB.
> + * Disallow a requested BAR size larger than 128 TB.
> + */
> + if (size < SZ_1M || (u64)size > (SZ_128G * 1024))
You could've used (SZ_1T * 128). But no need to respin just for this.
- Mani
--
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