On Thu, Mar 23, 2017 at 03:44:18PM +0100, Lucas Stach wrote:
> On i.MX6QP, due to hardware erratum ERR009619, the PRE clocks may be
> stalled during the power up sequencing of the PU power domain. As this
> may lead to a complete loss of display output, the recommended
> workaround is to keep the PU domain enabled during normal system
> operation.
>
> Implement this by rejecting the domain power down request on the
> affected SoC.
>
> Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> ---
> drivers/soc/imx/gpc.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/soc/imx/gpc.c b/drivers/soc/imx/gpc.c
> index 4294287e5f6c..599e1e46f694 100644
> --- a/drivers/soc/imx/gpc.c
> +++ b/drivers/soc/imx/gpc.c
> @@ -45,6 +45,7 @@ struct imx_pm_domain {
> unsigned int reg_offs;
> signed char cntr_pdn_bit;
> unsigned int ipg_rate_mhz;
> + bool allow_dynamic_pd;
> };
>
> static inline struct imx_pm_domain *
> @@ -59,6 +60,9 @@ static int imx6_pm_domain_power_off(struct generic_pm_domain *genpd)
> int iso, iso2sw;
> u32 val;
>
> + if (!pd->allow_dynamic_pd)
> + return -EBUSY;
> +
> /* Read ISO and ISO2SW power down delays */
> regmap_read(pd->regmap, pd->reg_offs + GPC_PGC_PUPSCR_OFFS, &val);
> iso = val & 0x3f;
> @@ -255,6 +259,7 @@ static struct imx_pm_domain imx_gpc_domains[] = {
> },
> .reg_offs = 0x260,
> .cntr_pdn_bit = 0,
> + .allow_dynamic_pd = true,
> }, {
> .base = {
> .name = "DISPLAY",
> @@ -263,23 +268,33 @@ static struct imx_pm_domain imx_gpc_domains[] = {
> },
> .reg_offs = 0x240,
> .cntr_pdn_bit = 4,
> + .allow_dynamic_pd = true,
> }
> };
>
> struct imx_gpc_dt_data {
> int num_domains;
> + bool err009619_present;
> };
>
> static const struct imx_gpc_dt_data imx6q_dt_data = {
> .num_domains = 2,
> + .err009619_present = false,
> +};
> +
> +static const struct imx_gpc_dt_data imx6qp_dt_data = {
> + .num_domains = 2,
> + .err009619_present = true,
> };
>
> static const struct imx_gpc_dt_data imx6sl_dt_data = {
> .num_domains = 3,
> + .err009619_present = false,
> };
>
> static const struct of_device_id imx_gpc_dt_ids[] = {
> { .compatible = "fsl,imx6q-gpc", .data = &imx6q_dt_data },
> + { .compatible = "fsl,imx6qp-gpc", .data = &imx6qp_dt_data },
> { .compatible = "fsl,imx6sl-gpc", .data = &imx6sl_dt_data },
> { }
> };
> @@ -377,6 +392,10 @@ static int imx_gpc_probe(struct platform_device *pdev)
> return ret;
> }
>
> + /* Disable PU power down in normal operation if ERR009619 is present */
> + if (of_id_data->err009619_present)
> + imx_gpc_domains[1].allow_dynamic_pd = false;
I'm uncomfortable with using hard-coded value indexing the
imx_gpc_domains array for a particular power domain. We already have a
couple of such uses in the code, and it becomes even more. Can we have
some defines or enumerations to help?
Shawn
> +
> if (!pgc_node) {
> ret = imx_gpc_old_dt_init(&pdev->dev, regmap,
> of_id_data->num_domains);
> --
> 2.11.0
>
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