| Message ID | 20180628231540.26633-1-joel@jms.id.au |
|---|---|
| State | New |
| Headers | show |
| Series | clk: aspeed: Support HPLL strapping on ast2400 | expand |
Quoting Joel Stanley (2018-06-28 16:15:40) > The HPLL can be configured through a register (SCU24), however some > platforms chose to configure it through the strapping settings and do > not use the register. This was not noticed as the logic for bit 18 in > SCU24 was confused: set means programmed, but the driver read it as set > means strapped. > > This gives us the correct HPLL value on Palmetto systems, from which > most of the peripheral clocks are generated. > > Fixes: 5eda5d79e4be ("clk: Add clock driver for ASPEED BMC SoCs") > Cc: stable@vger.kernel.org # v4.15 > Reviewed-by: Cédric Le Goater <clg@kaod.org> > Signed-off-by: Joel Stanley <joel@jms.id.au> > --- Do you want this merged for -rc5? It sounds like on some systems this is a problem, but I don't know if these systems are supposed to work yet or not, so priority of this fix is not easy for me to understand.
Hi Stephen, On 7 July 2018 at 03:55, Stephen Boyd <sboyd@kernel.org> wrote: > Quoting Joel Stanley (2018-06-28 16:15:40) >> The HPLL can be configured through a register (SCU24), however some >> platforms chose to configure it through the strapping settings and do >> not use the register. This was not noticed as the logic for bit 18 in >> SCU24 was confused: set means programmed, but the driver read it as set >> means strapped. >> >> This gives us the correct HPLL value on Palmetto systems, from which >> most of the peripheral clocks are generated. >> >> Fixes: 5eda5d79e4be ("clk: Add clock driver for ASPEED BMC SoCs") >> Cc: stable@vger.kernel.org # v4.15 >> Reviewed-by: Cédric Le Goater <clg@kaod.org> >> Signed-off-by: Joel Stanley <joel@jms.id.au> >> --- > > Do you want this merged for -rc5? It sounds like on some systems this is > a problem, but I don't know if these systems are supposed to work yet or > not, so priority of this fix is not easy for me to understand. > Sure, some more background: We did not notice this until we attempted to use the clock for the mtd driver. However, this clock is used for the kernel clocksource, so eg. sleep 1 takes two seconds to complete. This affects all of the systems I have access to. I suggest we merge for4.18, and keep the cc: stable so it can be backported to the stable trees. Cheers, Joel
Quoting Joel Stanley (2018-07-10 22:53:52) > Hi Stephen, > > On 7 July 2018 at 03:55, Stephen Boyd <sboyd@kernel.org> wrote: > > Quoting Joel Stanley (2018-06-28 16:15:40) > >> The HPLL can be configured through a register (SCU24), however some > >> platforms chose to configure it through the strapping settings and do > >> not use the register. This was not noticed as the logic for bit 18 in > >> SCU24 was confused: set means programmed, but the driver read it as set > >> means strapped. > >> > >> This gives us the correct HPLL value on Palmetto systems, from which > >> most of the peripheral clocks are generated. > >> > >> Fixes: 5eda5d79e4be ("clk: Add clock driver for ASPEED BMC SoCs") > >> Cc: stable@vger.kernel.org # v4.15 > >> Reviewed-by: Cédric Le Goater <clg@kaod.org> > >> Signed-off-by: Joel Stanley <joel@jms.id.au> > >> --- > > > > Do you want this merged for -rc5? It sounds like on some systems this is > > a problem, but I don't know if these systems are supposed to work yet or > > not, so priority of this fix is not easy for me to understand. > > > > Sure, some more background: > > We did not notice this until we attempted to use the clock for the mtd > driver. However, this clock is used for the kernel clocksource, so eg. > sleep 1 takes two seconds to complete. This affects all of the systems > I have access to. > > I suggest we merge for4.18, and keep the cc: stable so it can be > backported to the stable trees. > Ok. Thanks! Applied to clk-fixes.
diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c index 38b366b00c57..2ef4ad7bdbdc 100644 --- a/drivers/clk/clk-aspeed.c +++ b/drivers/clk/clk-aspeed.c @@ -24,7 +24,7 @@ #define ASPEED_MPLL_PARAM 0x20 #define ASPEED_HPLL_PARAM 0x24 #define AST2500_HPLL_BYPASS_EN BIT(20) -#define AST2400_HPLL_STRAPPED BIT(18) +#define AST2400_HPLL_PROGRAMMED BIT(18) #define AST2400_HPLL_BYPASS_EN BIT(17) #define ASPEED_MISC_CTRL 0x2c #define UART_DIV13_EN BIT(12) @@ -565,29 +565,45 @@ builtin_platform_driver(aspeed_clk_driver); static void __init aspeed_ast2400_cc(struct regmap *map) { struct clk_hw *hw; - u32 val, freq, div; + u32 val, div, clkin, hpll; + const u16 hpll_rates[][4] = { + {384, 360, 336, 408}, + {400, 375, 350, 425}, + }; + int rate; /* * CLKIN is the crystal oscillator, 24, 48 or 25MHz selected by * strapping */ regmap_read(map, ASPEED_STRAP, &val); - if (val & CLKIN_25MHZ_EN) - freq = 25000000; - else if (val & AST2400_CLK_SOURCE_SEL) - freq = 48000000; - else - freq = 24000000; - hw = clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, freq); - pr_debug("clkin @%u MHz\n", freq / 1000000); + rate = (val >> 8) & 3; + if (val & CLKIN_25MHZ_EN) { + clkin = 25000000; + hpll = hpll_rates[1][rate]; + } else if (val & AST2400_CLK_SOURCE_SEL) { + clkin = 48000000; + hpll = hpll_rates[0][rate]; + } else { + clkin = 24000000; + hpll = hpll_rates[0][rate]; + } + hw = clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, clkin); + pr_debug("clkin @%u MHz\n", clkin / 1000000); /* * High-speed PLL clock derived from the crystal. This the CPU clock, - * and we assume that it is enabled + * and we assume that it is enabled. It can be configured through the + * HPLL_PARAM register, or set to a specified frequency by strapping. */ regmap_read(map, ASPEED_HPLL_PARAM, &val); - WARN(val & AST2400_HPLL_STRAPPED, "hpll is strapped not configured"); - aspeed_clk_data->hws[ASPEED_CLK_HPLL] = aspeed_ast2400_calc_pll("hpll", val); + if (val & AST2400_HPLL_PROGRAMMED) + hw = aspeed_ast2400_calc_pll("hpll", val); + else + hw = clk_hw_register_fixed_rate(NULL, "hpll", "clkin", 0, + hpll * 1000000); + + aspeed_clk_data->hws[ASPEED_CLK_HPLL] = hw; /* * Strap bits 11:10 define the CPU/AHB clock frequency ratio (aka HCLK)
The HPLL can be configured through a register (SCU24), however some platforms chose to configure it through the strapping settings and do not use the register. This was not noticed as the logic for bit 18 in SCU24 was confused: set means programmed, but the driver read it as set means strapped. This gives us the correct HPLL value on Palmetto systems, from which most of the peripheral clocks are generated. Fixes: 5eda5d79e4be ("clk: Add clock driver for ASPEED BMC SoCs") Cc: stable@vger.kernel.org # v4.15 Reviewed-by: Cédric Le Goater <clg@kaod.org> Signed-off-by: Joel Stanley <joel@jms.id.au> --- drivers/clk/clk-aspeed.c | 42 +++++++++++++++++++++++++++------------- 1 file changed, 29 insertions(+), 13 deletions(-)