Hi,
On Fri, Nov 19, 2021 at 3:12 AM Mårten Lindahl <marten.lindahl@xxxxxxxx> wrote:
>
> The TMOUT register is always set with a full value for every transfer,
> which (with a 200MHz clock) will give a full DRTO of ~84 milliseconds.
> This is normally good enough to complete the request, but setting a full
> value makes it impossible to test shorter timeouts, when for example
> testing data read times on different SD cards.
>
> Add a function to set any value smaller than the maximum of 0xFFFFFF.
>
> Signed-off-by: Mårten Lindahl <marten.lindahl@xxxxxxxx>
> ---
>
> v2:
> - Calculate new value before checking boundaries
> - Include CLKDIV register to get proper value
>
> v3:
> - Use 'if-else' instead of 'goto'
> - Don't touch response field when maximize data field
>
> v4:
> - Prevent 32bit divider overflow by splitting the operation
> - Changed %06x to %#08x as suggested by Doug
> - Rephrased commit msg as suggested by Doug
>
> v5:
> - Use u32 type for CPU reg access
> - Make tmp 64bit to handle INT_MAX parameters
>
> drivers/mmc/host/dw_mmc.c | 29 ++++++++++++++++++++++++++++-
> 1 file changed, 28 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index d977f34f6b55..210252d33b95 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1283,6 +1283,33 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
> mci_writel(host, CTYPE, (slot->ctype << slot->id));
> }
>
> +static void dw_mci_set_data_timeout(struct dw_mci *host,
> + unsigned int timeout_ns)
> +{
> + u32 clk_div, tmout;
> + unsigned long tmp;
> +
> + clk_div = (mci_readl(host, CLKDIV) & 0xFF) * 2;
> + if (clk_div == 0)
> + clk_div = 1;
> +
> + tmp = DIV_ROUND_UP_ULL((u64)timeout_ns * host->bus_hz, NSEC_PER_SEC);
> + tmp = DIV_ROUND_UP_ULL(tmp, clk_div);
Unfortunately I don't think "tmp" is always a 64-bit type (unsigned
long is only 32-bit on many devices). As per my response just now to
your v4, I'd be happy with going back to a normal DIV_ROUND_UP.
However, if you want to keep it extra safe and keep the _ULL version
then you should change tmp to "u64".
In any case:
Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
