scsi: ufs: exynos: Add EXYNOS_UFS_OPT_TIMER_TICK_SELECT option

This option is intended to be set for SoCs that have HCI_V2P1_CTRL register
and can select their tick source via IA_TICK_SEL bit.

Source clock selection for timer tick
0x0 = Bus clock (aclk)
0x1 = Function clock (mclk)
Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Link: https://lore.kernel.org/r/20240426122004.2249178-4-peter.griffin@linaro.orgAcked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Will McVicker <willmcvicker@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/ufs/host/ufs-exynos.c

@@ -50,6 +50,8 @@
 #define HCI_ERR_EN_N_LAYER	0x80
 #define HCI_ERR_EN_T_LAYER	0x84
 #define HCI_ERR_EN_DME_LAYER	0x88
+#define HCI_V2P1_CTRL		0x8C
+#define IA_TICK_SEL		BIT(16)
 #define HCI_CLKSTOP_CTRL	0xB0
 #define REFCLKOUT_STOP		BIT(4)
 #define MPHY_APBCLK_STOP	BIT(3)
@@ -1005,6 +1007,13 @@ static void exynos_ufs_fit_aggr_timeout(struct exynos_ufs *ufs)
 {
 	u32 val;
 
+	/* Select function clock (mclk) for timer tick */
+	if (ufs->opts & EXYNOS_UFS_OPT_TIMER_TICK_SELECT) {
+		val = hci_readl(ufs, HCI_V2P1_CTRL);
+		val |= IA_TICK_SEL;
+		hci_writel(ufs, val, HCI_V2P1_CTRL);
+	}
+
 	val = exynos_ufs_calc_time_cntr(ufs, IATOVAL_NSEC / CNTR_DIV_VAL);
 	hci_writel(ufs, val & CNT_VAL_1US_MASK, HCI_1US_TO_CNT_VAL);
 }

drivers/ufs/host/ufs-exynos.h

@@ -222,6 +222,7 @@ struct exynos_ufs {
 #define EXYNOS_UFS_OPT_USE_SW_HIBERN8_TIMER	BIT(4)
 #define EXYNOS_UFS_OPT_SKIP_CONFIG_PHY_ATTR	BIT(5)
 #define EXYNOS_UFS_OPT_UFSPR_SECURE		BIT(6)
+#define EXYNOS_UFS_OPT_TIMER_TICK_SELECT	BIT(7)
 };
 
 #define for_each_ufs_rx_lane(ufs, i) \