ARM: mx6: Add PCI express clock configuration

Split the SATA clock enabling function and add PCI express clock
enabling function. The SATA clock enabling function starts up the
100MHz SATA reference PLL in ENET_PLL register, but the code can
be re-used to enable the 125MHz PCIe reference in ENET_PLL, so pull
this code into separate function. Moreover, add the PCIe clock
enabling code.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Eric Nelson <eric.nelson@boundarydevices.com>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>

2 files changed, 66 insertions, 10 deletions

diff --git a/arch/arm/cpu/armv7/mx6/clock.c b/arch/arm/cpu/armv7/mx6/clock.c
index 5617a41..61f71cf 100644
--- a/arch/arm/cpu/armv7/mx6/clock.c
+++ b/arch/arm/cpu/armv7/mx6/clock.c
@@ -412,17 +412,12 @@ u32 imx_get_fecclk(void)
 	return decode_pll(PLL_ENET, MXC_HCLK);
 }
 
-int enable_sata_clock(void)
+static int enable_enet_pll(uint32_t en)
 {
-	u32 reg = 0;
-	s32 timeout = 100000;
 	struct mxc_ccm_reg *const imx_ccm
 		= (struct mxc_ccm_reg *) CCM_BASE_ADDR;
-
-	/* Enable sata clock */
-	reg = readl(&imx_ccm->CCGR5); /* CCGR5 */
-	reg |= MXC_CCM_CCGR5_SATA_MASK;
-	writel(reg, &imx_ccm->CCGR5);
+	s32 timeout = 100000;
+	u32 reg = 0;
 
 	/* Enable PLLs */
 	reg = readl(&imx_ccm->analog_pll_enet);
@@ -437,10 +432,70 @@ int enable_sata_clock(void)
 		return -EIO;
 	reg &= ~BM_ANADIG_PLL_SYS_BYPASS;
 	writel(reg, &imx_ccm->analog_pll_enet);
-	reg |= BM_ANADIG_PLL_ENET_ENABLE_SATA;
+	reg |= en;
 	writel(reg, &imx_ccm->analog_pll_enet);
+	return 0;
+}
 
-	return 0 ;
+static void ungate_sata_clock(void)
+{
+	struct mxc_ccm_reg *const imx_ccm =
+		(struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	/* Enable SATA clock. */
+	setbits_le32(&imx_ccm->CCGR5, MXC_CCM_CCGR5_SATA_MASK);
+}
+
+static void ungate_pcie_clock(void)
+{
+	struct mxc_ccm_reg *const imx_ccm =
+		(struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	/* Enable PCIe clock. */
+	setbits_le32(&imx_ccm->CCGR4, MXC_CCM_CCGR4_PCIE_MASK);
+}
+
+int enable_sata_clock(void)
+{
+	ungate_sata_clock();
+	return enable_enet_pll(BM_ANADIG_PLL_ENET_ENABLE_SATA);
+}
+
+int enable_pcie_clock(void)
+{
+	struct anatop_regs *anatop_regs =
+		(struct anatop_regs *)ANATOP_BASE_ADDR;
+	struct mxc_ccm_reg *ccm_regs = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+
+	/*
+	 * Here be dragons!
+	 *
+	 * The register ANATOP_MISC1 is not documented in the Freescale
+	 * MX6RM. The register that is mapped in the ANATOP space and
+	 * marked as ANATOP_MISC1 is actually documented in the PMU section
+	 * of the datasheet as PMU_MISC1.
+	 *
+	 * Switch LVDS clock source to SATA (0xb), disable clock INPUT and
+	 * enable clock OUTPUT. This is important for PCI express link that
+	 * is clocked from the i.MX6.
+	 */
+#define ANADIG_ANA_MISC1_LVDSCLK1_IBEN		(1 << 12)
+#define ANADIG_ANA_MISC1_LVDSCLK1_OBEN		(1 << 10)
+#define ANADIG_ANA_MISC1_LVDS1_CLK_SEL_MASK	0x0000001F
+	clrsetbits_le32(&anatop_regs->ana_misc1,
+			ANADIG_ANA_MISC1_LVDSCLK1_IBEN |
+			ANADIG_ANA_MISC1_LVDS1_CLK_SEL_MASK,
+			ANADIG_ANA_MISC1_LVDSCLK1_OBEN | 0xb);
+
+	/* PCIe reference clock sourced from AXI. */
+	clrbits_le32(&ccm_regs->cbcmr, MXC_CCM_CBCMR_PCIE_AXI_CLK_SEL);
+
+	/* Party time! Ungate the clock to the PCIe. */
+	ungate_sata_clock();
+	ungate_pcie_clock();
+
+	return enable_enet_pll(BM_ANADIG_PLL_ENET_ENABLE_SATA |
+			       BM_ANADIG_PLL_ENET_ENABLE_PCIE);
 }
 
 unsigned int mxc_get_clock(enum mxc_clock clk)
diff --git a/arch/arm/include/asm/arch-mx6/clock.h b/arch/arm/include/asm/arch-mx6/clock.h
index e31ba0a..1b4ded7 100644
--- a/arch/arm/include/asm/arch-mx6/clock.h
+++ b/arch/arm/include/asm/arch-mx6/clock.h
@@ -55,6 +55,7 @@ unsigned int mxc_get_clock(enum mxc_clock clk);
 void enable_ocotp_clk(unsigned char enable);
 void enable_usboh3_clk(unsigned char enable);
 int enable_sata_clock(void);
+int enable_pcie_clock(void);
 int enable_i2c_clk(unsigned char enable, unsigned i2c_num);
 void enable_ipu_clock(void);
 int enable_fec_anatop_clock(enum enet_freq freq);