[U-Boot] [PATCH] ARM: omap3: Implement dpll5 (HSUSB clk) workaround for OMAP36xx/AM/DM37xx according to errata sprz318e.

[Andreas Naumann]

In chapter 'Advisory 2.1 USB Host Clock Drift Causes USB Spec Non-compliance in Certain Configurations' of the TI Errata it is recommended to use certain div/mult values for the DPLL5 clock setup.
So far u-boot used the old 34xx values, so I added the errata recommended values specificly for 36xx init only.
Also, the FSEL registers exist no longer, so removed them from init.

Tested this on a AM3703 board with 19.2MHz oscillator, which previously couldnt lock the dpll5 (kernel complained). As a consequence the EHCI USB port wasnt usable in U-Boot and kernel. With this patch, kernel panics disappear and USB working fine in u-boot and kernel.

Signed-off-by: Andreas Naumann <anaumann at ultratronik.de>
---
 arch/arm/cpu/armv7/omap3/clock.c               | 20 +++++++++++++++++++-
 arch/arm/cpu/armv7/omap3/lowlevel_init.S       | 18 ++++++++++++++++++
 arch/arm/include/asm/arch-omap3/clocks_omap3.h | 22 ++++++++++++++++++++++
 3 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/arch/arm/cpu/armv7/omap3/clock.c b/arch/arm/cpu/armv7/omap3/clock.c
index 81cc859..68833ba 100644
--- a/arch/arm/cpu/armv7/omap3/clock.c
+++ b/arch/arm/cpu/armv7/omap3/clock.c
@@ -491,6 +491,24 @@ static void dpll4_init_36xx(u32 sil_index, u32 clk_index)
 	wait_on_value(ST_PERIPH_CLK, 2, &prcm_base->idlest_ckgen, LDELAY);
 }
 
+static void dpll5_init_36xx(u32 sil_index, u32 clk_index)
+{
+	struct prcm *prcm_base = (struct prcm *)PRCM_BASE;
+	dpll_param *ptr = (dpll_param *) get_36x_per2_dpll_param();
+
+	/* Moving it to the right sysclk base */
+	ptr = ptr + clk_index;
+
+	/* PER2 DPLL (DPLL5) */
+	sr32(&prcm_base->clken2_pll, 0, 3, PLL_STOP);
+	wait_on_value(1, 0, &prcm_base->idlest2_ckgen, LDELAY);
+	sr32(&prcm_base->clksel5_pll, 0, 5, ptr->m2); /* set M2 (usbtll_fck) */
+	sr32(&prcm_base->clksel4_pll, 8, 11, ptr->m); /* set m (11-bit multiplier) */
+	sr32(&prcm_base->clksel4_pll, 0, 7, ptr->n); /* set n (7-bit divider)*/
+	sr32(&prcm_base->clken2_pll, 0, 3, PLL_LOCK);   /* lock mode */
+	wait_on_value(1, 1, &prcm_base->idlest2_ckgen, LDELAY);
+}
+
 static void mpu_init_36xx(u32 sil_index, u32 clk_index)
 {
 	struct prcm *prcm_base = (struct prcm *)PRCM_BASE;
@@ -595,7 +613,7 @@ void prcm_init(void)
 
 		dpll3_init_36xx(0, clk_index);
 		dpll4_init_36xx(0, clk_index);
-		dpll5_init_34xx(0, clk_index);
+		dpll5_init_36xx(0, clk_index);
 		iva_init_36xx(0, clk_index);
 		mpu_init_36xx(0, clk_index);
 
diff --git a/arch/arm/cpu/armv7/omap3/lowlevel_init.S b/arch/arm/cpu/armv7/omap3/lowlevel_init.S
index eacfef8..66a1b48 100644
--- a/arch/arm/cpu/armv7/omap3/lowlevel_init.S
+++ b/arch/arm/cpu/armv7/omap3/lowlevel_init.S
@@ -480,6 +480,19 @@ per_36x_dpll_param:
 .word 26000,    432,   12,     9,      16,     9,     4,      3,      1
 .word 38400,    360,   15,     9,      16,     5,     4,      3,      1
 
+per2_36x_dpll_param:
+/* 12MHz */
+.word PER2_36XX_M_12, PER2_36XX_N_12, 0, PER2_36XX_M2_12
+/* 13MHz */
+.word PER2_36XX_M_13, PER2_36XX_N_13, 0, PER2_36XX_M2_13
+/* 19.2MHz */
+.word PER2_36XX_M_19P2, PER2_36XX_N_19P2, 0, PER2_36XX_M2_19P2
+/* 26MHz */
+.word PER2_36XX_M_26, PER2_36XX_N_26, 0, PER2_36XX_M2_26
+/* 38.4MHz */
+.word PER2_36XX_M_38P4, PER2_36XX_N_38P4, 0, PER2_36XX_M2_38P4
+
+
 ENTRY(get_36x_mpu_dpll_param)
 	adr	r0, mpu_36x_dpll_param
 	mov	pc, lr
@@ -499,3 +512,8 @@ ENTRY(get_36x_per_dpll_param)
 	adr	r0, per_36x_dpll_param
 	mov	pc, lr
 ENDPROC(get_36x_per_dpll_param)
+
+ENTRY(get_36x_per2_dpll_param)
+	adr	r0, per2_36x_dpll_param
+	mov	pc, lr
+ENDPROC(get_36x_per2_dpll_param)
diff --git a/arch/arm/include/asm/arch-omap3/clocks_omap3.h b/arch/arm/include/asm/arch-omap3/clocks_omap3.h
index 5925ac4..59e61e8 100644
--- a/arch/arm/include/asm/arch-omap3/clocks_omap3.h
+++ b/arch/arm/include/asm/arch-omap3/clocks_omap3.h
@@ -336,4 +336,26 @@
 #define PER_36XX_FSEL_38P4	0x07
 #define PER_36XX_M2_38P4	0x09
 
+/* 36XX PER2 DPLL */
+
+#define PER2_36XX_M_12		0x50
+#define PER2_36XX_N_12		0x00
+#define PER2_36XX_M2_12		0x08
+
+#define PER2_36XX_M_13		0x1BB
+#define PER2_36XX_N_13		0x05
+#define PER2_36XX_M2_13		0x08
+
+#define PER2_36XX_M_19P2		0x32
+#define PER2_36XX_N_19P2		0x00
+#define PER2_36XX_M2_19P2		0x08
+
+#define PER2_36XX_M_26		0x1BB
+#define PER2_36XX_N_26		0x0B
+#define PER2_36XX_M2_26		0x08
+
+#define PER2_36XX_M_38P4		0x19
+#define PER2_36XX_N_38P4		0x00
+#define PER2_36XX_M2_38P4		0x08
+
 #endif	/* endif _CLOCKS_OMAP3_H_ */
-- 
1.8.3.1