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SubjectRe: [PATCH 5/7] soundwire: intel: follow documentation sequences for SHIM registers
On 11-03-20, 17:10, Pierre-Louis Bossart wrote:
> From: Rander Wang <rander.wang@intel.com>
>
> Somehow the existing code is not aligned with the steps described in
> the documentation, refactor code and make sure the register

Is the documentation available public space so that we can correct

> programming sequences are correct.
>
> This includes making sure SHIM_SYNC is programmed only once, before
> the first link is powered on.
>
> Note that the SYNCPRD value is tied only to the XTAL value and not the
> current bus frequency or the frame rate.
>
> Signed-off-by: Rander Wang <rander.wang@intel.com>
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> ---
> drivers/soundwire/intel.c | 186 ++++++++++++++++++++++++++++----------
> 1 file changed, 139 insertions(+), 47 deletions(-)
>
> diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
> index 3c271a8044b8..9c6514fe1284 100644
> --- a/drivers/soundwire/intel.c
> +++ b/drivers/soundwire/intel.c
> @@ -46,7 +46,8 @@
> #define SDW_SHIM_LCTL_SPA BIT(0)
> #define SDW_SHIM_LCTL_CPA BIT(8)
>
> -#define SDW_SHIM_SYNC_SYNCPRD_VAL 0x176F
> +#define SDW_SHIM_SYNC_SYNCPRD_VAL_24 (24000 / SDW_CADENCE_GSYNC_KHZ - 1)
> +#define SDW_SHIM_SYNC_SYNCPRD_VAL_38_4 (38400 / SDW_CADENCE_GSYNC_KHZ - 1)
> #define SDW_SHIM_SYNC_SYNCPRD GENMASK(14, 0)
> #define SDW_SHIM_SYNC_SYNCCPU BIT(15)
> #define SDW_SHIM_SYNC_CMDSYNC_MASK GENMASK(19, 16)
> @@ -283,11 +284,48 @@ static int intel_link_power_up(struct sdw_intel *sdw)
> {
> unsigned int link_id = sdw->instance;
> void __iomem *shim = sdw->link_res->shim;
> + u32 *shim_mask = sdw->link_res->shim_mask;

this is a local pointer, so the one defined previously is not used.

> + struct sdw_bus *bus = &sdw->cdns.bus;
> + struct sdw_master_prop *prop = &bus->prop;
> int spa_mask, cpa_mask;
> - int link_control, ret;
> + int link_control;
> + int ret = 0;
> + u32 syncprd;
> + u32 sync_reg;
>
> mutex_lock(sdw->link_res->shim_lock);
>
> + /*
> + * The hardware relies on an internal counter,
> + * typically 4kHz, to generate the SoundWire SSP -
> + * which defines a 'safe' synchronization point
> + * between commands and audio transport and allows for
> + * multi link synchronization. The SYNCPRD value is
> + * only dependent on the oscillator clock provided to
> + * the IP, so adjust based on _DSD properties reported
> + * in DSDT tables. The values reported are based on
> + * either 24MHz (CNL/CML) or 38.4 MHz (ICL/TGL+).

Sorry this looks quite bad to read, we have 80 chars, so please use
like below:

/*
* The hardware relies on an internal counter, typically 4kHz,
* to generate the SoundWire SSP - which defines a 'safe'
* synchronization point between commands and audio transport
* and allows for multi link synchronization. The SYNCPRD value
* is only dependent on the oscillator clock provided to
* the IP, so adjust based on _DSD properties reported in DSDT
* tables. The values reported are based on either 24MHz
* (CNL/CML) or 38.4 MHz (ICL/TGL+).
*/

--
~Vinod

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