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SubjectRe: [PATCH v1 07/10] scsi: ufs: introduce UFSHCD_QUIRK_DME_PEER_ACCESS_AUTO_MODE quirk
From
2015-05-18 0:55 GMT+09:00 Yaniv Gardi <ygardi@codeaurora.org>:
> 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@codeaurora.org>
>
> ---
> 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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