Hi Leonard,
On 11/23/19 6:45 AM, Leonard Crestez wrote:
> Add driver for dynamic scaling the DDR Controller on imx8m chips. Actual
> frequency switching is implemented inside TF-A, this driver wraps the
> SMC calls and synchronizes the clk tree.
>
> The DRAM clocks on imx8m have the following structure (abridged):
>
> +----------+ |\ +------+
> | dram_pll |-------|M| dram_core | |
> +----------+ |U|---------->| D |
> /--|X| | D |
> dram_alt_root | |/ | R |
> | | C |
> +---------+ | |
> |FIX DIV/4| | |
> +---------+ | |
> composite: | | |
> +----------+ | | |
> | dram_alt |----/ | |
> +----------+ | |
> | dram_apb |-------------------->| |
> +----------+ +------+
>
> The dram_pll is used for higher rates and dram_alt is used for lower
> rates. The dram_alt and dram_apb clocks are "imx composite" and their
> parent can also be modified.
>
> This driver will prepare/enable the new parents ahead of switching (so
> that the expected roots are enabled) and afterwards it will call
> clk_set_parent to ensure the parents in clock framework are up-to-date.
>
> The driver relies on dram_pll dram_alt and dram_apb being marked with
> CLK_GET_RATE_NOCACHE for rate updates.
>
> Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
> Acked-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
> ---
> drivers/devfreq/Kconfig | 9 +
> drivers/devfreq/Makefile | 1 +
> drivers/devfreq/imx8m-ddrc.c | 465 +++++++++++++++++++++++++++++++++++
> 3 files changed, 475 insertions(+)
> create mode 100644 drivers/devfreq/imx8m-ddrc.c
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index 59027d7ddf2a..5eac479dd05f 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -89,10 +89,19 @@ config ARM_EXYNOS_BUS_DEVFREQ
> Each memory bus group could contain many memoby bus block. It reads
> PPMU counters of memory controllers by using DEVFREQ-event device
> and adjusts the operating frequencies and voltages with OPP support.
> This does not yet operate with optimal voltages.
>
> +config ARM_IMX8M_DDRC_DEVFREQ
> + tristate "i.MX8M DDRC DEVFREQ Driver"
> + depends on ARCH_MXC && HAVE_ARM_SMCCC
I'll edit it as following and applied it.
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 5eac479dd05f..38a94df749a2 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -93,7 +93,8 @@ config ARM_EXYNOS_BUS_DEVFREQ
config ARM_IMX8M_DDRC_DEVFREQ
tristate "i.MX8M DDRC DEVFREQ Driver"
- depends on ARCH_MXC && HAVE_ARM_SMCCC
+ depends on (ARCH_MXC && HAVE_ARM_SMCCC) || \
+ (COMPILE_TEST && HAVE_ARM_SMCCC)
(snip)
--
Best Regards,
Chanwoo Choi
Samsung Electronics
