Alexandru Gagniuc (mr.nuke.me@gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/4593
-gerrit
commit 3fc8d1795e63aaa551502f8e7c4e1ea61faa6b6b Author: Alexandru Gagniuc mr.nuke.me@gmail.com Date: Tue Dec 31 13:20:27 2013 -0500
cpu/allwinner/a10: Add low-level helpers for DRAM clock control
PLL5 is special in that it controls the DRAM clock, and requires a fine-grained low-level control which will be needed by raminit code. This change also brings functionality which will be needed by raminit.
Change-Id: I25ecc91aa2154e504ceebb9003a5e5728d47f4a3 Signed-off-by: Alexandru Gagniuc mr.nuke.me@gmail.com --- src/cpu/allwinner/a10/clock.c | 81 +++++++++++++++++++++++++++++++++++++++++++ src/cpu/allwinner/a10/clock.h | 28 +++++++++++++++ 2 files changed, 109 insertions(+)
diff --git a/src/cpu/allwinner/a10/clock.c b/src/cpu/allwinner/a10/clock.c index bc78743..0fc2698 100644 --- a/src/cpu/allwinner/a10/clock.c +++ b/src/cpu/allwinner/a10/clock.c @@ -9,6 +9,8 @@
#include <arch/io.h>
+static struct a10_ccm *const ccm = (void *)A1X_CCM_BASE; + /** * \brief Enable the clock source for the peripheral * @@ -40,3 +42,82 @@ void a1x_periph_clock_disable(enum a1x_clken periph) reg32 &= ~(1 << (periph & 0x1f)); write32(reg32, addr); } + +/** + * \brief Configure PLL5 factors + * + * This is a low-level accessor to configure the divisors and multipliers of + * PLL5. PLL5 uses two factors to multiply the 24MHz oscillator clock to + * generate a pre-clock. The pre-divided clock is then divided by one of two + * independent divisors, one for DRAM, and another for peripherals clocked from + * this PLL. If the PLL was previously disabled, this function will enable it. + * Other than that, this function only modifies these factors, and leaves the + * other settings unchanged. + * + * The output clocks are give by the following formulas: + * + * Pre-clock = (24 MHz * N * K) <- Must be between 240MHz and 2GHz + * DRAM clock = pre / M + * Other module = pre / P + * + * It is the caller's responsibility to make sure the pre-divided clock falls + * within the operational range of the PLL, and that the divisors and + * multipliers are within their ranges. + * + * @param[in] mul_n Multiplier N, between 0 and 32 + * @param[in] mul_k Multiplier K, between 1 and 4 + * @param[in] div_m DRAM clock divisor, between 1 and 4 + * @param[in] exp_div_p Peripheral clock divisor exponent, between 0 and 3 + * (P = 1/2/4/8, respectively) + */ +void a1x_pll5_configure(u8 mul_n, u8 mul_k, u8 div_m, u8 exp_div_p) +{ + u32 reg32; + + reg32 = read32(&ccm->pll5_cfg); + reg32 &= ~(PLL5_FACTOR_M_MASK | PLL5_FACTOR_N_MASK | + PLL5_FACTOR_K_MASK | PLL5_DIV_EXP_P_MASK); + /* The M1 factor is not documented in the datasheet, and the reference + * raminit code does not use it. Whether this is a fractional divisor, + * or an additional divisor is unknown, so don't use it for now */ + reg32 &= ~PLL5_FACTOR_M1_MASK; + reg32 |= (PLL5_FACTOR_M(div_m) | PLL5_FACTOR_N(mul_n) | + PLL5_FACTOR_K(mul_k) | PLL5_DIV_EXP_P(exp_div_p)); + reg32 |= PLL5_PLL_ENABLE; + write32(reg32, &ccm->pll5_cfg); +} + +/** + * \brief Enable the clock output to DRAM chips + * + * This enables the DRAM clock to be sent to DRAM chips. This should normally be + * done after PLL5 is configured and locked. Note that the clock may be gated, + * and also needs to be ungated in order to reach the DDR chips. + * Also see @ref clock_ungate_dram_clk_output + */ +void a1x_pll5_enable_dram_clock_output(void) +{ + setbits_le32(&ccm->pll5_cfg, PLL5_DDR_CLK_OUT_EN); +} + +/** + * \brief Ungate the clock to DRAM chips + * + * Although the DRAM clock output may be enabled, it is by default gated. It + * needs to be ungated before reaching DRAM. + */ +void a1x_ungate_dram_clock_output(void) +{ + setbits_le32(&ccm->dram_clk_cfg, DRAM_CTRL_DCLK_OUT); +} + +/** + * \brief Gate the clock to DRAM chips + * + * Disable the clock to DRAM without altering PLL configuration, by closing the + * DRAM clock gate. + */ +void a1x_gate_dram_clock_output(void) +{ + clrbits_le32(&ccm->dram_clk_cfg, DRAM_CTRL_DCLK_OUT); +} diff --git a/src/cpu/allwinner/a10/clock.h b/src/cpu/allwinner/a10/clock.h index 9656469..41400ab 100644 --- a/src/cpu/allwinner/a10/clock.h +++ b/src/cpu/allwinner/a10/clock.h @@ -43,6 +43,29 @@ #define APB1_RAT_M_MASK 0x1f << 0) #define APB1_RAT_M(n) (((n) & 0x1f) << 0)
+/* PLL5_CFG values */ +#define PLL5_PLL_ENABLE (1 << 31) +#define PLL5_OUT_BYPASS_EN (1 << 30) +#define PLL5_DDR_CLK_OUT_EN (1 << 29) +#define PLL5_DIV_EXP_P_MASK (0x3 << 16) +#define PLL5_DIV_EXP_P(ep) ((ep << 16) & PLL5_DIV_EXP_P_MASK) +#define PLL5_DIV_P_1 (0x0 << 16) +#define PLL5_DIV_P_2 (0x1 << 16) +#define PLL5_DIV_P_4 (0x2 << 16) +#define PLL5_DIV_P_8 (0x3 << 16) +#define PLL5_FACTOR_N_MASK (0x1f << 8) +#define PLL5_FACTOR_N(n) ((n << 8) & PLL5_FACTOR_N_MASK) +#define PLL5_LDO_EN (1 << 7) +#define PLL5_FACTOR_K_MASK (0x3 << 4) +#define PLL5_FACTOR_K(k) ((((k) - 1) << 4) & PLL5_FACTOR_K_MASK) +#define PLL5_FACTOR_M1_MASK (0x3 << 2) +#define PLL5_FACTOR_M1(m1) (((m1) << 2) & PLL5_FACTOR_M1_MASK) +#define PLL5_FACTOR_M_MASK (0x3 << 0) +#define PLL5_FACTOR_M(m) ((((m) - 1) << 0) & PLL5_FACTOR_M_MASK) + +/* DRAM_CLK values*/ +#define DRAM_CTRL_DCLK_OUT (1 << 15) + /** * \brief Clock gating definitions * @@ -228,4 +251,9 @@ struct a10_ccm { void a1x_periph_clock_enable(enum a1x_clken periph); void a1x_periph_clock_disable(enum a1x_clken periph);
+void a1x_pll5_configure(u8 mul_n, u8 mul_k, u8 div_m, u8 exp_div_p); +void a1x_pll5_enable_dram_clock_output(void); +void a1x_ungate_dram_clock_output(void); +void a1x_gate_dram_clock_output(void); + #endif /* CPU_ALLWINNER_A10_CLOCK_H */