diff options
Diffstat (limited to 'src/soc/sifive/fu540')
| -rw-r--r-- | src/soc/sifive/fu540/clock.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/soc/sifive/fu540/clock.c b/src/soc/sifive/fu540/clock.c index 9b396a78a1..a98a09367c 100644 --- a/src/soc/sifive/fu540/clock.c +++ b/src/soc/sifive/fu540/clock.c @@ -72,6 +72,12 @@ static struct prci_ctlr *prci = (void *)FU540_PRCI; #define PRCI_CORECLKSEL_CORECLKSEL 1 +#define PRCI_DEVICESRESET_DDR_CTRL_RST_N(x) (((x) & 0x1) << 0) +#define PRCI_DEVICESRESET_DDR_AXI_RST_N(x) (((x) & 0x1) << 1) +#define PRCI_DEVICESRESET_DDR_AHB_RST_N(x) (((x) & 0x1) << 2) +#define PRCI_DEVICESRESET_DDR_PHY_RST_N(x) (((x) & 0x1) << 3) +#define PRCI_DEVICESRESET_GEMGXL_RST_N(x) (((x) & 0x1) << 5) + /* * Set coreclk according to the SiFive FU540-C000 Manual * https://www.sifive.com/documentation/chips/freedom-u540-c000-manual/ @@ -198,5 +204,33 @@ void clock_init(void) // put DDR and ethernet in reset write32(&prci->devicesresetreg, 0); + init_pll_ddr(); + + // The following code and its comments is mostly derived from the SiFive + // u540 bootloader. + // https://github.com/sifive/freedom-u540-c000-bootloader + + // get DDR out of reset + write32(&prci->devicesresetreg, PRCI_DEVICESRESET_DDR_CTRL_RST_N(1)); + + // HACK to get the '1 full controller clock cycle'. + asm volatile ("fence"); + + // get DDR out of reset + write32(&prci->devicesresetreg, + PRCI_DEVICESRESET_DDR_CTRL_RST_N(1) | + PRCI_DEVICESRESET_DDR_AXI_RST_N(1) | + PRCI_DEVICESRESET_DDR_AHB_RST_N(1) | + PRCI_DEVICESRESET_DDR_PHY_RST_N(1)); + + // HACK to get the '1 full controller clock cycle'. + asm volatile ("fence"); + + // These take like 16 cycles to actually propagate. We can't go sending + // stuff before they come out of reset. So wait. + // TODO: Add a register to read the current reset states, or DDR Control + // device? + for (int i = 0; i < 256; i++) + asm volatile ("nop"); } |