[U-Boot] [PATCH] mx6qsabreauto: Fix the EIM clock for the mx6qp variant

[Fabio Estevam <festevam@gmail.com>]

From: Fabio Estevam <fabio.estevam@nxp.com>

On the MX6Q the aclk_eim_slow_podf field is '1' after POR, while on the
MX6DQP it is '3'.

This makes the EIM clock to be only 66MHz on the mx6qp variant, instead of
132 MHz.

Instead of relying on the POR values for the CSMR1 register, make sure to
manually configure the clk_eim_slow_sel field as '00' so that EIM clock is
derived from AXI clock and the aclk_eim_slow_podf field as '1' so that EIM
clock can be AXI clock divided by 2.

This way a consistent EIM clock frequency is configured for all the mx6
variants.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
---
 board/freescale/mx6qsabreauto/mx6qsabreauto.c | 28 +++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/board/freescale/mx6qsabreauto/mx6qsabreauto.c b/board/freescale/mx6qsabreauto/mx6qsabreauto.c
index 5fca4d1..51bbbc4 100644
--- a/board/freescale/mx6qsabreauto/mx6qsabreauto.c
+++ b/board/freescale/mx6qsabreauto/mx6qsabreauto.c
@@ -231,6 +231,33 @@ static void eimnor_cs_setup(void)
 	set_chipselect_size(CS0_128);
 }
 
+static void eim_clk_setup(void)
+{
+	struct mxc_ccm_reg *imx_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+	int cscmr1, ccgr6;
+
+
+	/* Turn off EIM clock */
+	ccgr6 = readl(&imx_ccm->CCGR6);
+	ccgr6 &= ~(0x3 << 10);
+	writel(ccgr6, &imx_ccm->CCGR6);
+
+	/*
+	 * Configure clk_eim_slow_sel = 00 --> derive clock from AXI clk root
+	 * and aclk_eim_slow_podf = 01 --> divide by 2
+	 * so that we can have EIM at the maximum clock of 132MHz
+	 */
+	cscmr1 = readl(&imx_ccm->cscmr1);
+	cscmr1 &= ~(MXC_CCM_CSCMR1_ACLK_EMI_SLOW_MASK |
+		    MXC_CCM_CSCMR1_ACLK_EMI_SLOW_PODF_MASK);
+	cscmr1 |= (1 << MXC_CCM_CSCMR1_ACLK_EMI_SLOW_PODF_OFFSET);
+	writel(cscmr1, &imx_ccm->cscmr1);
+
+	/* Turn on EIM clock */
+	ccgr6 |= (0x3 << 10);
+	writel(ccgr6, &imx_ccm->CCGR6);
+}
+
 static void setup_iomux_eimnor(void)
 {
 	imx_iomux_v3_setup_multiple_pads(eimnor_pads, ARRAY_SIZE(eimnor_pads));
@@ -519,6 +546,7 @@ int board_early_init_f(void)
 #ifdef CONFIG_NAND_MXS
 	setup_gpmi_nand();
 #endif
+	eim_clk_setup();
 
 	return 0;
 }
-- 
2.7.4