Re: [PATCH v1 07/10] scsi: ufs: introduce UFSHCD_QUIRK_DME_PEER_ACCESS_AUTO_MODE quirk

[Akinobu Mita]

2015-05-18 0:55 GMT+09:00 Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>:
> Some UFS host controllers may only allow accessing the peer DME attribute
> in AUTO mode (FAST AUTO or SLOW AUTO) hence we had added a quirk for
> switching to AUTO power mode before accessing the peer DME attribute.
>
> Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>
>
> ---
>  drivers/scsi/ufs/ufshcd.c | 31 +++++++++++++++++++++++++++++++
>  drivers/scsi/ufs/ufshcd.h |  7 +++++++
>  2 files changed, 38 insertions(+)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index a274df9..014f1c0 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -188,6 +188,8 @@ static int ufshcd_host_reset_and_restore(struct ufs_hba *hba);
>  static irqreturn_t ufshcd_intr(int irq, void *__hba);
>  static int ufshcd_config_pwr_mode(struct ufs_hba *hba,
>                 struct ufs_pa_layer_attr *desired_pwr_mode);
> +static int ufshcd_change_power_mode(struct ufs_hba *hba,
> +                            struct ufs_pa_layer_attr *pwr_mode);
>
>  static inline int ufshcd_enable_irq(struct ufs_hba *hba)
>  {
> @@ -2156,6 +2158,31 @@ int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
>         };
>         const char *get = action[!!peer];
>         int ret;
> +       struct ufs_pa_layer_attr orig_pwr_info;
> +       struct ufs_pa_layer_attr temp_pwr_info;
> +       bool pwr_mode_change = false;
> +
> +       if (peer && (hba->quirks & UFSHCD_QUIRK_DME_PEER_ACCESS_AUTO_MODE)) {
> +               orig_pwr_info = hba->pwr_info;
> +               temp_pwr_info = orig_pwr_info;
> +
> +               if (orig_pwr_info.pwr_tx == FAST_MODE ||
> +                   orig_pwr_info.pwr_rx == FAST_MODE) {
> +                       temp_pwr_info.pwr_tx = FASTAUTO_MODE;
> +                       temp_pwr_info.pwr_rx = FASTAUTO_MODE;
> +                       pwr_mode_change = true;
> +               } else if (orig_pwr_info.pwr_tx == SLOW_MODE ||
> +                   orig_pwr_info.pwr_rx == SLOW_MODE) {
> +                       temp_pwr_info.pwr_tx = SLOWAUTO_MODE;
> +                       temp_pwr_info.pwr_rx = SLOWAUTO_MODE;
> +                       pwr_mode_change = true;
> +               }
> +               if (pwr_mode_change) {
> +                       ret = ufshcd_change_power_mode(hba, &temp_pwr_info);

I'm a bit worried that this could cause an infinite recursion if
someone adds ufshcd_dme_peer_get() in ufshcd_change_power_mode()
for debugging or investigation.

So isn't it better to add note in code comment, or detect infinite
recursion?
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