On 12 October 2017 at 12:32, Shah, Nehal-bakulchandra
<Nehal-Bakulchandra.shah@xxxxxxx> wrote:
> From: Shah Nehal-Bakulchandra <Nehal-bakulchandra.Shah@xxxxxxx>
>
> This patch supports HS400 for AMD upcoming emmc 5.0 controller.The
> HS400 and HS200 mode requires hardware work around also. This patch
> adds the quirks for the same.
By looking at the changes in the patch, obviously you make changes to
the core, but I think the reasons to why explicitly needs to be stated
also in the change log.
>
> Signed-off-by: Shah Nehal-Bakulchandra <Nehal-bakulchandra.Shah@xxxxxxx>
> ---
> drivers/mmc/core/mmc.c | 6 +--
> drivers/mmc/host/sdhci-acpi.c | 89 +++++++++++++++++++++++++++++++++++++++++++
> drivers/mmc/host/sdhci.c | 3 +-
> drivers/mmc/host/sdhci.h | 5 +++
> include/linux/mmc/host.h | 6 +++
> 5 files changed, 105 insertions(+), 4 deletions(-)
Please split the core changes into a separate patch.
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 4ffea14..7bf3736 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1164,7 +1164,7 @@ static int mmc_select_hs400(struct mmc_card *card)
>
> /* Set host controller to HS timing */
> mmc_set_timing(card->host, MMC_TIMING_MMC_HS);
> -
> + host->ios.transition = HS200_TO_HS_TO_HS400;
> /* Reduce frequency to HS frequency */
> max_dtr = card->ext_csd.hs_max_dtr;
> mmc_set_clock(host, max_dtr);
> @@ -1196,7 +1196,7 @@ static int mmc_select_hs400(struct mmc_card *card)
> mmc_hostname(host), err);
> return err;
> }
> -
> + host->ios.transition = SWITCHING_TO_HS400;
> /* Set host controller to HS400 timing and frequency */
> mmc_set_timing(host, MMC_TIMING_MMC_HS400);
> mmc_set_bus_speed(card);
> @@ -1204,7 +1204,7 @@ static int mmc_select_hs400(struct mmc_card *card)
> err = mmc_switch_status(card);
> if (err)
> goto out_err;
> -
> + host->ios.transition = SWITCHED_TO_HS400;
> return 0;
We have some other host drivers that also needs to follow a specific
sequence while switching to HS400. Those drivers makes use of the
->prepare_hs400_tuning() callback. Have you explored that option, and
if so, why exactly doesn't it work for you?
[...]
> /*
> * End of controller registers.
> */
> @@ -571,6 +574,8 @@ struct sdhci_ops {
> void (*set_bus_width)(struct sdhci_host *host, int width);
> void (*platform_send_init_74_clocks)(struct sdhci_host *host,
> u8 power_mode);
> + /* ios for transiton phase for going to hs400 */
> + void (*set_platform_hs400_transition)(struct sdhci_host *host);
In general we avoid adding new sdhci callbacks, but instead we try to
use the sdhci core as a set of library functions.
However, I leave this to managed by Adrian, as we decide this on case
by case basis.
> unsigned int (*get_ro)(struct sdhci_host *host);
> void (*reset)(struct sdhci_host *host, u8 mask);
> int (*platform_execute_tuning)(struct sdhci_host *host, u32 opcode);
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index ebd1ceb..0d0d5d3 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -77,6 +77,12 @@ struct mmc_ios {
> #define MMC_SET_DRIVER_TYPE_D 3
>
> bool enhanced_strobe; /* hs400es selection */
> +
> + unsigned int transition; /* track transition modes (hs200 hs400) */
> +
> +#define HS200_TO_HS_TO_HS400 1
> +#define SWITCHING_TO_HS400 2
> +#define SWITCHED_TO_HS400 3
> };
>
> struct mmc_host;
> --
> 1.9.1
>
Kind regards
Uffe
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