On Mon, 10 Sep 2018 at 23:48, Cédric Le Goater clg@kaod.org wrote:
The AHB clock is used by the FMC/SPI controllers.
Signed-off-by: Cédric Le Goater clg@kaod.org
arch/arm/include/asm/arch-aspeed/scu_ast2500.h | 2 ++ include/dt-bindings/clock/ast2500-scu.h | 1 + drivers/clk/aspeed/clk_ast2500.c | 12 ++++++++++++ 3 files changed, 15 insertions(+)
diff --git a/arch/arm/include/asm/arch-aspeed/scu_ast2500.h b/arch/arm/include/asm/arch-aspeed/scu_ast2500.h index 4988ced7ddcc..6a90ded752ad 100644 --- a/arch/arm/include/asm/arch-aspeed/scu_ast2500.h +++ b/arch/arm/include/asm/arch-aspeed/scu_ast2500.h @@ -11,6 +11,8 @@ #define SCU_HWSTRAP_VGAMEM_MASK (3 << SCU_HWSTRAP_VGAMEM_SHIFT) #define SCU_HWSTRAP_MAC1_RGMII (1 << 6) #define SCU_HWSTRAP_MAC2_RGMII (1 << 7) +#define SCU_HWSTRAP_AXIAHB_DIV_SHIFT 9 +#define SCU_HWSTRAP_AXIAHB_DIV_MASK (0x7 << SCU_HWSTRAP_AXIAHB_DIV_SHIFT) #define SCU_HWSTRAP_DDR4 (1 << 24) #define SCU_HWSTRAP_CLKIN_25MHZ (1 << 23)
diff --git a/include/dt-bindings/clock/ast2500-scu.h b/include/dt-bindings/clock/ast2500-scu.h index 4803abe9f628..03e6d16d3de0 100644 --- a/include/dt-bindings/clock/ast2500-scu.h +++ b/include/dt-bindings/clock/ast2500-scu.h @@ -17,6 +17,7 @@ #define BCLK_MACCLK 103 #define BCLK_SDCLK 104 #define BCLK_ARMCLK 105 +#define BCLK_HCLK 106
I like how the clocks are grouped in this file. Are we confident that HCLK is going in the correct spot?
#define MCLK_DDR 201
diff --git a/drivers/clk/aspeed/clk_ast2500.c b/drivers/clk/aspeed/clk_ast2500.c index 526470051c5d..c55f8d5ae30d 100644 --- a/drivers/clk/aspeed/clk_ast2500.c +++ b/drivers/clk/aspeed/clk_ast2500.c @@ -143,6 +143,18 @@ static ulong ast2500_clk_get_rate(struct clk *clk) rate = rate / apb_div; } break;
case BCLK_HCLK:{ulong ahb_div = 1 + ((readl(&priv->scu->hwstrap)& SCU_HWSTRAP_AXIAHB_DIV_MASK)>> SCU_HWSTRAP_AXIAHB_DIV_SHIFT);ulong axi_div = 2;rate = ast2500_get_hpll_rate(clkin, readl(&priv->scu->h_pll_param));rate = rate / axi_div / ahb_div;
In the kernel driver I wrote it as:
rate / (axi_div + ahb_div)
I know that the maths works, but do the numbers come out as we expect when doing integer division?