soc/sifive/fu540: Update clock settings according SiFive bootloader

The documentation unfortunately doesn't match what SiFive uses in their FSBL.
Use the same values as in FSBL to make DDR RAM work.

Change-Id: I844cc41ed197333adeae495e71ea70b4a9603650
Signed-off-by: Philipp Hug <philipp@hug.cx>
Reviewed-on: https://review.coreboot.org/28582
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/sifive/fu540/clock.c

@@ -46,11 +46,13 @@ static struct prci_ctlr *prci = (void *)FU540_PRCI;
 #define PRCI_COREPLLCFG0_DIVQ_SHIFT 15
 #define PRCI_COREPLLCFG0_RANGE_SHIFT 18
 #define PRCI_COREPLLCFG0_BYPASS_SHIFT 24
+#define PRCI_COREPLLCFG0_FSE_SHIFT 25
 #define PRCI_COREPLLCFG0_DIVR_MASK (0x03f << PRCI_COREPLLCFG0_DIVR_SHIFT)
 #define PRCI_COREPLLCFG0_DIVF_MASK (0x1ff << PRCI_COREPLLCFG0_DIVF_SHIFT)
 #define PRCI_COREPLLCFG0_DIVQ_MASK (0x007 << PRCI_COREPLLCFG0_DIVQ_SHIFT)
 #define PRCI_COREPLLCFG0_RANGE_MASK (0x07 << PRCI_COREPLLCFG0_RANGE_SHIFT)
 #define PRCI_COREPLLCFG0_BYPASS_MASK (0x1 << PRCI_COREPLLCFG0_BYPASS_SHIFT)
+#define PRCI_COREPLLCFG0_FSE_MASK (0x1 << PRCI_COREPLLCFG0_FSE_SHIFT)
 
 #define PRCI_DDRPLLCFG0_LOCK (1u << 31)
 #define PRCI_DDRPLLCFG0_DIVR_SHIFT 0
@@ -58,11 +60,13 @@ static struct prci_ctlr *prci = (void *)FU540_PRCI;
 #define PRCI_DDRPLLCFG0_DIVQ_SHIFT 15
 #define PRCI_DDRPLLCFG0_RANGE_SHIFT 18
 #define PRCI_DDRPLLCFG0_BYPASS_SHIFT 24
+#define PRCI_DDRPLLCFG0_FSE_SHIFT 25
 #define PRCI_DDRPLLCFG0_DIVR_MASK (0x03f << PRCI_DDRPLLCFG0_DIVR_SHIFT)
 #define PRCI_DDRPLLCFG0_DIVF_MASK (0x1ff << PRCI_DDRPLLCFG0_DIVF_SHIFT)
 #define PRCI_DDRPLLCFG0_DIVQ_MASK (0x007 << PRCI_DDRPLLCFG0_DIVQ_SHIFT)
 #define PRCI_DDRPLLCFG0_RANGE_MASK (0x07 << PRCI_DDRPLLCFG0_RANGE_SHIFT)
 #define PRCI_DDRPLLCFG0_BYPASS_MASK (0x1 << PRCI_DDRPLLCFG0_BYPASS_SHIFT)
+#define PRCI_DDRPLLCFG0_FSE_MASK (0x1 << PRCI_DDRPLLCFG0_FSE_SHIFT)
 
 #define PRCI_DDRPLLCFG1_MASK (1u << 31)
 
@@ -83,18 +87,30 @@ static struct prci_ctlr *prci = (void *)FU540_PRCI;
 #define PRCI_CORECLK_DIVF 59
 #define PRCI_CORECLK_DIVQ 2
 #define PRCI_CORECLK_RANGE 4
+#define PRCI_CORECLK_BYPASS 0
+#define PRCI_CORECLK_FSE 1
 
 /*
  * Section 7.4.3: DDR and Ethernet Subsystem Clocking and Reset
+ *
+ * Unfortunately the documentation example doesn't match the HiFive
+ * Unleashed board settings.
+ * Configuration values taken from SiFive FSBL:
+ * https://github.com/sifive/freedom-u540-c000-bootloader/blob/master/fsbl/main.c
+ *
+ * DDRPLL is set up for 933 MHz output frequency.
+ * divr = 0, divf = 55 (3730 MHz VCO), divq = 2
+ *
  * GEMGXLPLL is set up for 125 MHz output frequency.
- * divr = 0, divf = 59 (4000 MHz VCO), divq = 5 DDRPLL is set up to run at the
+ * divr = 0, divf = 59 (4000 MHz VCO), divq = 5
- * memory MT/s divided by 4.
  */
 
 #define PRCI_DDRCLK_DIVR 0
-#define PRCI_DDRCLK_DIVF 59
+#define PRCI_DDRCLK_DIVF 55
-#define PRCI_DDRCLK_DIVQ 5
+#define PRCI_DDRCLK_DIVQ 2
 #define PRCI_DDRCLK_RANGE 4
+#define PRCI_DDRCLK_BYPASS 0
+#define PRCI_DDRCLK_FSE 1
 
 // 33.33 Mhz after reset
 #define FU540_BASE_FQY 33330
@@ -108,11 +124,14 @@ static void init_coreclk(void)
 	u32 c = read32(&prci->corepllcfg0);
 	clrsetbits_le32(&c, PRCI_COREPLLCFG0_DIVR_MASK
 		| PRCI_COREPLLCFG0_DIVF_MASK | PRCI_COREPLLCFG0_DIVQ_MASK
-		| PRCI_COREPLLCFG0_RANGE_MASK | PRCI_COREPLLCFG0_BYPASS_MASK,
+		| PRCI_COREPLLCFG0_RANGE_MASK | PRCI_COREPLLCFG0_BYPASS_MASK
+		| PRCI_COREPLLCFG0_FSE_MASK,
 		(PRCI_CORECLK_DIVR << PRCI_COREPLLCFG0_DIVR_SHIFT)
 		| (PRCI_CORECLK_DIVF << PRCI_COREPLLCFG0_DIVF_SHIFT)
 		| (PRCI_CORECLK_DIVQ << PRCI_COREPLLCFG0_DIVQ_SHIFT)
-		| (PRCI_CORECLK_RANGE << PRCI_COREPLLCFG0_RANGE_SHIFT));
+		| (PRCI_CORECLK_RANGE << PRCI_COREPLLCFG0_RANGE_SHIFT)
+		| (PRCI_CORECLK_BYPASS << PRCI_COREPLLCFG0_BYPASS_SHIFT)
+		| (PRCI_CORECLK_FSE << PRCI_COREPLLCFG0_FSE_SHIFT));
 	write32(&prci->corepllcfg0, c);
 
 	// wait for PLL lock
@@ -134,11 +153,14 @@ static void init_pll_ddr(void)
 	u32 c = read32(&prci->ddrpllcfg0);
 	clrsetbits_le32(&c, PRCI_DDRPLLCFG0_DIVR_MASK
 		| PRCI_DDRPLLCFG0_DIVF_MASK | PRCI_DDRPLLCFG0_DIVQ_MASK
-		| PRCI_DDRPLLCFG0_RANGE_MASK | PRCI_DDRPLLCFG0_BYPASS_MASK,
+		| PRCI_DDRPLLCFG0_RANGE_MASK | PRCI_DDRPLLCFG0_BYPASS_MASK
+		| PRCI_DDRPLLCFG0_FSE_MASK,
 		(PRCI_DDRCLK_DIVR << PRCI_DDRPLLCFG0_DIVR_SHIFT)
 		| (PRCI_DDRCLK_DIVF << PRCI_DDRPLLCFG0_DIVF_SHIFT)
 		| (PRCI_DDRCLK_DIVQ << PRCI_DDRPLLCFG0_DIVQ_SHIFT)
-		| (PRCI_DDRCLK_RANGE << PRCI_DDRPLLCFG0_RANGE_SHIFT));
+		| (PRCI_DDRCLK_RANGE << PRCI_DDRPLLCFG0_RANGE_SHIFT)
+		| (PRCI_DDRCLK_BYPASS << PRCI_DDRPLLCFG0_BYPASS_SHIFT)
+		| (PRCI_DDRCLK_FSE << PRCI_DDRPLLCFG0_FSE_SHIFT));
 	write32(&prci->ddrpllcfg0, c);
 
 	// wait for PLL lock