Re: [PATCH 3/3] OMAP36xx PM: Updated C state latencies for OMAP3630

[Kevin Hilman <khilman@ti.com>]

Vishwanath BS <vishwanath.bs@ti.com> writes:

> This patch has changes to update the C state latencies for OMAP3630 and
> disables the useless C-States, keeping only the optimized ones with their
> corresponding measured latencies. 

I think "useless" vs. "optimized" here are not the right words, and
doesn't summarize the problem being solved.

If I understood Nicole and Vincent's summary it was that there is no
significant power savings between some of the states, so they are not
necessary.

Also, I believe Nicole & Vincent's research applies to both 34xx and
36xx.

> Only 4 C-states are kept instead of 7
> C-States:
> * C1 . MPU WFI clock gated + Core autogating
> * C3 . MPU CSWR + Core inactive
> * C5 . MPU CSWR + Core CSWR
> * C7 . MPU OFF + Core OFF
>
> Thanks to Nicole Chaloub<n-chalhoub@ti.com> and Vincent Bour <v-bour@ti.com>
> for their investigation.
>
> Tested on ZOOM3 board using latest pm branch.
>
> Signed-off-by: Vishwanath BS <vishwanath.bs@ti.com>
> ---
>  arch/arm/mach-omap2/board-3630sdp.c |   19 +++++++++++++++++++
>  arch/arm/mach-omap2/board-zoom.c    |   19 +++++++++++++++++++

Why are these added as board-specific changes?

If these are to be the default 3630 CPUidle states, add a default 36xx
cpuidle_params_table along side the 34xx one and have CPUidle pick the
right one at runtime.

Kevin

>  2 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/board-3630sdp.c b/arch/arm/mach-omap2/board-3630sdp.c
> index 6264564..8d05fc9
> --- a/arch/arm/mach-omap2/board-3630sdp.c
> +++ b/arch/arm/mach-omap2/board-3630sdp.c
> @@ -25,6 +25,24 @@
>  #include "board-flash.h"
>  #include "mux.h"
>  #include "sdram-hynix-h8mbx00u0mer-0em.h"
> +#include "pm.h"
> +
> +static struct cpuidle_params omap36xx_cpuidle_params_table[] = {
> +	/* C1 */
> +	{1, 74, 78, 152},
> +	/* C2 */
> +	{0, 165, 90, 255},
> +	/* C3 */
> +	{1, 163, 180, 345},
> +	/* C4 */
> +	{0, 2852, 605, 3457},
> +	/* C5 */
> +	{1, 800, 366, 2120},
> +	/* C6 */
> +	{0, 4080, 801, 4881},
> +	/* C7 */
> +	{1, 4300, 8794, 159000},
> +};
>  
>  #if defined(CONFIG_SMC91X) || defined(CONFIG_SMC91X_MODULE)
>  
> @@ -212,6 +230,7 @@ static void __init omap_sdp_init(void)
>  	board_flash_init(sdp_flash_partitions, chip_sel_sdp);
>  	enable_board_wakeup_source();
>  	usb_ehci_init(&ehci_pdata);
> +	omap3_pm_init_cpuidle(omap36xx_cpuidle_params_table);
>  }
>  
>  MACHINE_START(OMAP_3630SDP, "OMAP 3630SDP board")
> diff --git a/arch/arm/mach-omap2/board-zoom.c b/arch/arm/mach-omap2/board-zoom.c
> index e26754c..6bd364a
> --- a/arch/arm/mach-omap2/board-zoom.c
> +++ b/arch/arm/mach-omap2/board-zoom.c
> @@ -30,6 +30,24 @@
>  #include "mux.h"
>  #include "sdram-micron-mt46h32m32lf-6.h"
>  #include "sdram-hynix-h8mbx00u0mer-0em.h"
> +#include "pm.h"
> +
> +static struct cpuidle_params omap36xx_cpuidle_params_table[] = {
> +	/* C1 */
> +	{1, 74, 78, 152},
> +	/* C2 */
> +	{0, 165, 90, 255},
> +	/* C3 */
> +	{1, 163, 180, 345},
> +	/* C4 */
> +	{0, 2852, 605, 3457},
> +	/* C5 */
> +	{1, 800, 366, 2120},
> +	/* C6 */
> +	{0, 4080, 801, 4881},
> +	/* C7 */
> +	{1, 4300, 8794, 159000},
> +};
>  
>  #define ZOOM3_EHCI_RESET_GPIO		64
>  
> @@ -126,6 +144,7 @@ static void __init omap_zoom_init(void)
>  		usb_ehci_init(&ehci_pdata);
>  	}
>  
> +	omap3_pm_init_cpuidle(omap36xx_cpuidle_params_table);
>  	board_nand_init(zoom_nand_partitions,
>  			ARRAY_SIZE(zoom_nand_partitions), ZOOM_NAND_CS);
>  	zoom_debugboard_init();