On Fri, 15 Sept 2023 at 11:44, Victor Shih <victorshihgli@xxxxxxxxx> wrote:
>
> From: Victor Shih <victor.shih@xxxxxxxxxxxxxxxxxxx>
>
> This is a UHS-II version of sdhci's set_timeout() operation.
This needs more explanations and justifications.
Other than that, the patch looks good to me!
Kind regards
Uffe
>
> Signed-off-by: Ben Chuang <ben.chuang@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
> Signed-off-by: Victor Shih <victor.shih@xxxxxxxxxxxxxxxxxxx>
> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
>
> Updates in V8:
> - Initialization be combined with declaration and realigned
> in sdhci_calc_timeout_uhs2().
> - Forward declare struct mmc_command in sdhci_uhs2.h.
>
> Updates in V6:
> - Use GENMASK() and FIELD_PREP() in some case.
> - Use sdhci_uhs2_mode() to simplify code.
> - Remove unnecessary functions.
>
> ---
>
> drivers/mmc/host/sdhci-uhs2.c | 72 +++++++++++++++++++++++++++++++++++
> drivers/mmc/host/sdhci-uhs2.h | 2 +
> 2 files changed, 74 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-uhs2.c b/drivers/mmc/host/sdhci-uhs2.c
> index 92fb69b7e209..d519e6ce6199 100644
> --- a/drivers/mmc/host/sdhci-uhs2.c
> +++ b/drivers/mmc/host/sdhci-uhs2.c
> @@ -13,6 +13,7 @@
> #include <linux/delay.h>
> #include <linux/module.h>
> #include <linux/iopoll.h>
> +#include <linux/bitfield.h>
>
> #include "sdhci.h"
> #include "sdhci-uhs2.h"
> @@ -142,6 +143,77 @@ static void sdhci_uhs2_set_power(struct sdhci_host *host, unsigned char mode, un
> }
> }
>
> +static u8 sdhci_calc_timeout_uhs2(struct sdhci_host *host, u8 *cmd_res, u8 *dead_lock)
> +{
> + /* timeout in us */
> + unsigned int dead_lock_timeout = 1 * 1000 * 1000;
> + unsigned int cmd_res_timeout = 5 * 1000;
> + unsigned int current_timeout;
> + u8 count;
> +
> + /*
> + * Figure out needed cycles.
> + * We do this in steps in order to fit inside a 32 bit int.
> + * The first step is the minimum timeout, which will have a
> + * minimum resolution of 6 bits:
> + * (1) 2^13*1000 > 2^22,
> + * (2) host->timeout_clk < 2^16
> + * =>
> + * (1) / (2) > 2^6
> + */
> + count = 0;
> + current_timeout = (1 << 13) * 1000 / host->timeout_clk;
> + while (current_timeout < cmd_res_timeout) {
> + count++;
> + current_timeout <<= 1;
> + if (count >= 0xF)
> + break;
> + }
> +
> + if (count >= 0xF) {
> + DBG("%s: Too large timeout 0x%x requested for CMD_RES!\n",
> + mmc_hostname(host->mmc), count);
> + count = 0xE;
> + }
> + *cmd_res = count;
> +
> + count = 0;
> + current_timeout = (1 << 13) * 1000 / host->timeout_clk;
> + while (current_timeout < dead_lock_timeout) {
> + count++;
> + current_timeout <<= 1;
> + if (count >= 0xF)
> + break;
> + }
> +
> + if (count >= 0xF) {
> + DBG("%s: Too large timeout 0x%x requested for DEADLOCK!\n",
> + mmc_hostname(host->mmc), count);
> + count = 0xE;
> + }
> + *dead_lock = count;
> +
> + return count;
> +}
> +
> +static void __sdhci_uhs2_set_timeout(struct sdhci_host *host)
> +{
> + u8 cmd_res, dead_lock;
> +
> + sdhci_calc_timeout_uhs2(host, &cmd_res, &dead_lock);
> + cmd_res |= FIELD_PREP(SDHCI_UHS2_TIMER_CTRL_DEADLOCK_MASK, dead_lock);
> + sdhci_writeb(host, cmd_res, SDHCI_UHS2_TIMER_CTRL);
> +}
> +
> +void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
> +{
> + __sdhci_set_timeout(host, cmd);
> +
> + if (sdhci_uhs2_mode(host))
> + __sdhci_uhs2_set_timeout(host);
> +}
> +EXPORT_SYMBOL_GPL(sdhci_uhs2_set_timeout);
> +
> /*****************************************************************************\
> * *
> * MMC callbacks *
> diff --git a/drivers/mmc/host/sdhci-uhs2.h b/drivers/mmc/host/sdhci-uhs2.h
> index 8253d50f7852..ccf4e1834c2d 100644
> --- a/drivers/mmc/host/sdhci-uhs2.h
> +++ b/drivers/mmc/host/sdhci-uhs2.h
> @@ -175,9 +175,11 @@
> #define SDHCI_UHS2_VENDOR_PTR 0xE8
>
> struct sdhci_host;
> +struct mmc_command;
>
> void sdhci_uhs2_dump_regs(struct sdhci_host *host);
> bool sdhci_uhs2_mode(struct sdhci_host *host);
> void sdhci_uhs2_reset(struct sdhci_host *host, u16 mask);
> +void sdhci_uhs2_set_timeout(struct sdhci_host *host, struct mmc_command *cmd);
>
> #endif /* __SDHCI_UHS2_H */
> --
> 2.25.1
>
