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scsi: ufs-qcom: enable host controller hardware clock gating

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The UTP controller has a number of internal clock gating cells (CGCs).
Internal hardware sub-modules within the UTP controller control the CGCs.
Hardware CGCs disable the clock to inactivate UTP sub-modules not involved
in a specific operation, UTP controller CGCs are by default disabled and
this change enables them (after every UFS link startup) to save some power
leakage.

Change-Id: I47bba62436c5913eb6755e59c36a11fea2e9468f
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
This commit is contained in:
Subhash Jadavani 2014-09-21 00:00:27 -07:00 • committed by David Keitel
parent 8c17ea4d5b
commit 9d89b6c4c8
2 changed files with 34 additions and 0 deletions
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19
drivers/scsi/ufs/ufs-qcom.c
View file

@ -264,6 +264,24 @@ out:
return ret; return ret;
} }
/*
* The UTP controller has a number of internal clock gating cells (CGCs).
* Internal hardware sub-modules within the UTP controller control the CGCs.
* Hardware CGCs disable the clock to inactivate UTP sub-modules not involved
* in a specific operation, UTP controller CGCs are by default disabled and
* this function enables them (after every UFS link startup) to save some power
* leakage.
*/
static void ufs_qcom_enable_hw_clk_gating(struct ufs_hba *hba)
{
ufshcd_writel(hba,
ufshcd_readl(hba, REG_UFS_CFG2) | REG_UFS_CFG2_CGC_EN_ALL,
REG_UFS_CFG2);
/* Ensure that HW clock gating is enabled before next operations */
mb();
}
static int ufs_qcom_hce_enable_notify(struct ufs_hba *hba, bool status) static int ufs_qcom_hce_enable_notify(struct ufs_hba *hba, bool status)
{ {
struct ufs_qcom_host *host = hba->priv; struct ufs_qcom_host *host = hba->priv;
@ -282,6 +300,7 @@ static int ufs_qcom_hce_enable_notify(struct ufs_hba *hba, bool status)
case POST_CHANGE: case POST_CHANGE:
/* check if UFS PHY moved from DISABLED to HIBERN8 */ /* check if UFS PHY moved from DISABLED to HIBERN8 */
err = ufs_qcom_check_hibern8(hba); err = ufs_qcom_check_hibern8(hba);
ufs_qcom_enable_hw_clk_gating(hba);
break; break;
default: default:
dev_err(hba->dev, "%s: invalid status %d\n", __func__, status); dev_err(hba->dev, "%s: invalid status %d\n", __func__, status);

15
include/linux/scsi/ufs/ufs-qcom.h
View file

@ -60,6 +60,21 @@ enum {
REG_UFS_HW_VERSION = 0xE4, REG_UFS_HW_VERSION = 0xE4,
}; };
/* bit definitions for REG_UFS_CFG2 register */
#define UAWM_HW_CGC_EN (1 << 0)
#define UARM_HW_CGC_EN (1 << 1)
#define TXUC_HW_CGC_EN (1 << 2)
#define RXUC_HW_CGC_EN (1 << 3)
#define DFC_HW_CGC_EN (1 << 4)
#define TRLUT_HW_CGC_EN (1 << 5)
#define TMRLUT_HW_CGC_EN (1 << 6)
#define OCSC_HW_CGC_EN (1 << 7)
#define REG_UFS_CFG2_CGC_EN_ALL (UAWM_HW_CGC_EN | UARM_HW_CGC_EN |\
TXUC_HW_CGC_EN | RXUC_HW_CGC_EN |\
DFC_HW_CGC_EN | TRLUT_HW_CGC_EN |\
TMRLUT_HW_CGC_EN | OCSC_HW_CGC_EN)
/* bit offset */ /* bit offset */
enum { enum {
OFFSET_UFS_PHY_SOFT_RESET = 1, OFFSET_UFS_PHY_SOFT_RESET = 1,