* [PATCH v2] mmc: mtk-sd: increase the minimum bus frequency
@ 2021-03-05 3:24 ` Weijie Gao
2021-03-05 8:47 ` Jaehoon Chung
2021-04-06 9:40 ` Peng Fan
0 siblings, 2 replies; 3+ messages in thread
From: Weijie Gao @ 2021-03-05 3:24 UTC (permalink / raw)
To: u-boot
With a 48MHz input clock, the lowest bus frequency can be as low as
48000000 / (4 * 4095) = 2930Hz. Such an extremely low frequency will cause
the mmc framework take seconds to finish the initialization.
Limiting the minimum bus frequency to a slightly higher value can solve the
issue without any side effects.
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
---
drivers/mmc/mtk-sd.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/mmc/mtk-sd.c b/drivers/mmc/mtk-sd.c
index 3b9c122..626a4d3 100644
--- a/drivers/mmc/mtk-sd.c
+++ b/drivers/mmc/mtk-sd.c
@@ -232,6 +232,8 @@
#define SCLK_CYCLES_SHIFT 20
+#define MIN_BUS_CLK 200000
+
#define CMD_INTS_MASK \
(MSDC_INT_CMDRDY | MSDC_INT_RSPCRCERR | MSDC_INT_CMDTMO)
@@ -1639,6 +1641,9 @@ static int msdc_drv_probe(struct udevice *dev)
else
cfg->f_min = host->src_clk_freq / (4 * 4095);
+ if (cfg->f_min < MIN_BUS_CLK)
+ cfg->f_min = MIN_BUS_CLK;
+
cfg->f_max = host->src_clk_freq;
cfg->b_max = 1024;
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH v2] mmc: mtk-sd: increase the minimum bus frequency
2021-03-05 3:24 ` [PATCH v2] mmc: mtk-sd: increase the minimum bus frequency Weijie Gao
@ 2021-03-05 8:47 ` Jaehoon Chung
2021-04-06 9:40 ` Peng Fan
1 sibling, 0 replies; 3+ messages in thread
From: Jaehoon Chung @ 2021-03-05 8:47 UTC (permalink / raw)
To: u-boot
On 3/5/21 12:24 PM, Weijie Gao wrote:
> With a 48MHz input clock, the lowest bus frequency can be as low as
> 48000000 / (4 * 4095) = 2930Hz. Such an extremely low frequency will cause
> the mmc framework take seconds to finish the initialization.
>
> Limiting the minimum bus frequency to a slightly higher value can solve the
> issue without any side effects.
>
> Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Best Regards,
Jaehoon Chung
> ---
> drivers/mmc/mtk-sd.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/mmc/mtk-sd.c b/drivers/mmc/mtk-sd.c
> index 3b9c122..626a4d3 100644
> --- a/drivers/mmc/mtk-sd.c
> +++ b/drivers/mmc/mtk-sd.c
> @@ -232,6 +232,8 @@
>
> #define SCLK_CYCLES_SHIFT 20
>
> +#define MIN_BUS_CLK 200000
> +
> #define CMD_INTS_MASK \
> (MSDC_INT_CMDRDY | MSDC_INT_RSPCRCERR | MSDC_INT_CMDTMO)
>
> @@ -1639,6 +1641,9 @@ static int msdc_drv_probe(struct udevice *dev)
> else
> cfg->f_min = host->src_clk_freq / (4 * 4095);
>
> + if (cfg->f_min < MIN_BUS_CLK)
> + cfg->f_min = MIN_BUS_CLK;
> +
> cfg->f_max = host->src_clk_freq;
>
> cfg->b_max = 1024;
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH v2] mmc: mtk-sd: increase the minimum bus frequency
2021-03-05 3:24 ` [PATCH v2] mmc: mtk-sd: increase the minimum bus frequency Weijie Gao
2021-03-05 8:47 ` Jaehoon Chung
@ 2021-04-06 9:40 ` Peng Fan
1 sibling, 0 replies; 3+ messages in thread
From: Peng Fan @ 2021-04-06 9:40 UTC (permalink / raw)
To: u-boot
> Subject: [PATCH v2] mmc: mtk-sd: increase the minimum bus frequency
Could you please rebase? I am not able to apply this patch.
Thanks,
Peng.
>
> With a 48MHz input clock, the lowest bus frequency can be as low as
> 48000000 / (4 * 4095) = 2930Hz. Such an extremely low frequency will cause
> the mmc framework take seconds to finish the initialization.
>
> Limiting the minimum bus frequency to a slightly higher value can solve the
> issue without any side effects.
>
> Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
> ---
> drivers/mmc/mtk-sd.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/mmc/mtk-sd.c b/drivers/mmc/mtk-sd.c index
> 3b9c122..626a4d3 100644
> --- a/drivers/mmc/mtk-sd.c
> +++ b/drivers/mmc/mtk-sd.c
> @@ -232,6 +232,8 @@
>
> #define SCLK_CYCLES_SHIFT 20
>
> +#define MIN_BUS_CLK 200000
> +
> #define CMD_INTS_MASK \
> (MSDC_INT_CMDRDY | MSDC_INT_RSPCRCERR |
> MSDC_INT_CMDTMO)
>
> @@ -1639,6 +1641,9 @@ static int msdc_drv_probe(struct udevice *dev)
> else
> cfg->f_min = host->src_clk_freq / (4 * 4095);
>
> + if (cfg->f_min < MIN_BUS_CLK)
> + cfg->f_min = MIN_BUS_CLK;
> +
> cfg->f_max = host->src_clk_freq;
>
> cfg->b_max = 1024;
> --
> 1.9.1
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-04-06 9:40 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <CGME20210305035552epcas1p3e806da9f37fc784409913ce169344414@epcas1p3.samsung.com>
2021-03-05 3:24 ` [PATCH v2] mmc: mtk-sd: increase the minimum bus frequency Weijie Gao
2021-03-05 8:47 ` Jaehoon Chung
2021-04-06 9:40 ` Peng Fan
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.