diff mbox

[U-Boot,2/4] Exynos5420: Remove code for enabling read leveling

Message ID 1400751183-432-1-git-send-email-akshay.s@samsung.com
State Changes Requested
Delegated to: Minkyu Kang
Headers show

Commit Message

Akshay Saraswat May 22, 2014, 9:33 a.m. UTC 
This patch intends to remove all code which enables hardware read
leveling. All characterization environments may not cope up with
h/w read leveling enabled, hence,  we need to disable this.
Also, disabling h/w read leveling improves the MIF LVcc value
(LVcc value is the value at which DDR will fail to work properly).
Improving LVcc means we have enough voltage margin for MIF.
When h/w leveling is enabled, we have almost zero volatge margin.

Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
---
 arch/arm/cpu/armv7/exynos/dmc_init_ddr3.c | 71 -------------------------------
 1 file changed, 71 deletions(-)

Comments

Simon Glass May 23, 2014, 11:22 p.m. UTC | #1 
Hi Akshay,

On 21 May 2014 23:33, Akshay Saraswat <akshay.s@samsung.com> wrote:
> This patch intends to remove all code which enables hardware read
> leveling. All characterization environments may not cope up with
> h/w read leveling enabled, hence,  we need to disable this.
> Also, disabling h/w read leveling improves the MIF LVcc value
> (LVcc value is the value at which DDR will fail to work properly).
> Improving LVcc means we have enough voltage margin for MIF.
> When h/w leveling is enabled, we have almost zero volatge margin.
>
> Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
> Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>

Acked-by: Simon Glass <sjg@chromium.org>

Does this mean that the read_leveling_enable structure member is not used?

Regards,
Simon
diff mbox

Patch

diff --git a/arch/arm/cpu/armv7/exynos/dmc_init_ddr3.c b/arch/arm/cpu/armv7/exynos/dmc_init_ddr3.c
index a89930b..0822323 100644
--- a/arch/arm/cpu/armv7/exynos/dmc_init_ddr3.c
+++ b/arch/arm/cpu/armv7/exynos/dmc_init_ddr3.c
@@ -524,77 +524,6 @@  int ddr3_mem_ctrl_init(int reset)
 			       &drex1->directcmd);
 		}
 
-		if (mem->read_leveling_enable) {
-			/* Set Read DQ Calibration */
-			val = (0x3 << DIRECT_CMD_BANK_SHIFT) | 0x4;
-			for (chip = 0; chip < mem->chips_to_configure; chip++) {
-				writel(val | (chip << DIRECT_CMD_CHIP_SHIFT),
-				       &drex0->directcmd);
-				writel(val | (chip << DIRECT_CMD_CHIP_SHIFT),
-				       &drex1->directcmd);
-			}
-
-			val = readl(&phy0_ctrl->phy_con1);
-			val |= READ_LEVELLING_DDR3;
-			writel(val, &phy0_ctrl->phy_con1);
-			val = readl(&phy1_ctrl->phy_con1);
-			val |= READ_LEVELLING_DDR3;
-			writel(val, &phy1_ctrl->phy_con1);
-
-			val = readl(&phy0_ctrl->phy_con2);
-			val |= (RDLVL_EN | RDLVL_INCR_ADJ);
-			writel(val, &phy0_ctrl->phy_con2);
-			val = readl(&phy1_ctrl->phy_con2);
-			val |= (RDLVL_EN | RDLVL_INCR_ADJ);
-			writel(val, &phy1_ctrl->phy_con2);
-
-			setbits_le32(&drex0->rdlvl_config,
-				     CTRL_RDLVL_DATA_ENABLE);
-			i = TIMEOUT;
-			while (((readl(&drex0->phystatus) & RDLVL_COMPLETE_CHO)
-				 != RDLVL_COMPLETE_CHO) && (i > 0)) {
-				/*
-				 * TODO(waihong): Comment on how long this take
-				 * to timeout
-				 */
-				sdelay(100);
-				i--;
-			}
-			if (!i)
-				return SETUP_ERR_RDLV_COMPLETE_TIMEOUT;
-
-			clrbits_le32(&drex0->rdlvl_config,
-				     CTRL_RDLVL_DATA_ENABLE);
-			setbits_le32(&drex1->rdlvl_config,
-				     CTRL_RDLVL_DATA_ENABLE);
-			i = TIMEOUT;
-			while (((readl(&drex1->phystatus) & RDLVL_COMPLETE_CHO)
-				 != RDLVL_COMPLETE_CHO) && (i > 0)) {
-				/*
-				 * TODO(waihong): Comment on how long this take
-				 * to timeout
-				 */
-				sdelay(100);
-				i--;
-			}
-			if (!i)
-				return SETUP_ERR_RDLV_COMPLETE_TIMEOUT;
-
-			clrbits_le32(&drex1->rdlvl_config,
-				     CTRL_RDLVL_DATA_ENABLE);
-
-			val = (0x3 << DIRECT_CMD_BANK_SHIFT);
-			for (chip = 0; chip < mem->chips_to_configure; chip++) {
-				writel(val | (chip << DIRECT_CMD_CHIP_SHIFT),
-				       &drex0->directcmd);
-				writel(val | (chip << DIRECT_CMD_CHIP_SHIFT),
-				       &drex1->directcmd);
-			}
-
-			update_reset_dll(&drex0->phycontrol0, DDR_MODE_DDR3);
-			update_reset_dll(&drex1->phycontrol0, DDR_MODE_DDR3);
-		}
-
 		/* Common Settings for Leveling */
 		val = PHY_CON12_RESET_VAL;
 		writel((val + n_lock_w_phy0), &phy0_ctrl->phy_con12);