Hi,
On Mon, Apr 21, 2014 at 10:48:18PM +0100, srinivas.kandagatla@xxxxxxxxxx wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
>
> This patch adds write delay parameter required after each write to controller
> registers on some of the SOCs like Qualcomm ones. The delay parameter will
> provide information on how many clock cycle delay required after each write.
>
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> ---
> drivers/mmc/host/mmci.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index 4f8d0ba..86bf330 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -55,6 +55,8 @@ static unsigned int fmax = 515633;
> * is asserted (likewise for RX)
> * @fifohalfsize: number of bytes that can be written when MCI_TXFIFOHALFEMPTY
> * is asserted (likewise for RX)
> + * @reg_write_delay: delay in number of clock cycles required after each write
> + * to controller registers.
> * @sdio: variant supports SDIO
> * @st_clkdiv: true if using a ST-specific clock divider algorithm
> * @blksz_datactrl16: true if Block size is at b16..b30 position in datactrl register
> @@ -72,6 +74,7 @@ struct variant_data {
> unsigned int datalength_bits;
> unsigned int fifosize;
> unsigned int fifohalfsize;
> + unsigned int reg_write_delay;
> bool sdio;
> bool st_clkdiv;
> bool blksz_datactrl16;
> @@ -178,7 +181,12 @@ static inline u32 mmci_readl(struct mmci_host *host, u32 off)
>
> static inline void mmci_writel(struct mmci_host *host, u32 data, u32 off)
> {
> + struct variant_data *var = host->variant;
> +
> writel(data, host->base + off);
> +
> + if (var->reg_write_delay && host->mclk)
> + udelay(1 + ((var->reg_write_delay * USEC_PER_SEC)/host->mclk));
looks like this should be quirk flag instead of a write delay... No
strong feelings though, but it looks like the following would be better,
perhaps:
if (host_is_qualcom(host))
udelay(1 + ((3 * USEC_PER_SEC)/host->mclk));
--
balbi
Attachment:
signature.asc
Description: Digital signature
