[PATCH 0/2] mmc: sdhci-of-aspeed: Fixes for AST2600 eMMC support

[PATCH 0/2] mmc: sdhci-of-aspeed: Fixes for AST2600 eMMC support

[Andrew Jeffery]

Hello,

The ASPEED SDHCI driver patches sent previously were based on testing on the
AST2500. The SD controllers in the 2500 and 2600 had the same register layout
according to the documentation, so we added the necessary devicetree compatible
string at the same time.

Now that I've got access to 2600 hardware with an eMMC chip I have a couple of
patches that are fixes enabling support for it. I don't think the first patch
is too controversial - in some cases we weren't ensuring the clock was enabled
before returning from the set_clock() callback.

I'm a bit unsure about the second patch though which enables use of
max-frequency in the devicetree, it feels a bit hacky so I'm looking for any
suggestions on the approach.

Please review!

Andrew

Andrew Jeffery (2):
  mmc: sdhci-of-aspeed: Uphold clocks-on post-condition of set_clock()
  mmc: sdhci-of-aspeed: Allow max-frequency limitation of SDCLK

 drivers/mmc/host/sdhci-of-aspeed.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

-- 
2.20.1


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[PATCH 1/2] mmc: sdhci-of-aspeed: Uphold clocks-on post-condition of set_clock()

[Andrew Jeffery]

The early-exit didn't seem to matter on the AST2500, but on the AST2600
the SD clock genuinely may not be running on entry to
aspeed_sdhci_set_clock(). Remove the early exit to ensure we always run
sdhci_enable_clk().

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 drivers/mmc/host/sdhci-of-aspeed.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
index d5acb5afc50f..a9175ca85696 100644
--- a/drivers/mmc/host/sdhci-of-aspeed.c
+++ b/drivers/mmc/host/sdhci-of-aspeed.c
@@ -55,9 +55,6 @@ static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
 	int div;
 	u16 clk;
 
-	if (clock == host->clock)
-		return;
-
 	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
 
 	if (clock == 0)
-- 
2.20.1


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Re: [PATCH 1/2] mmc: sdhci-of-aspeed: Uphold clocks-on post-condition of set_clock()

[Ulf Hansson]

On Fri, 30 Aug 2019 at 09:46, Andrew Jeffery <andrew@aj.id.au> wrote:
>
> The early-exit didn't seem to matter on the AST2500, but on the AST2600
> the SD clock genuinely may not be running on entry to
> aspeed_sdhci_set_clock(). Remove the early exit to ensure we always run
> sdhci_enable_clk().
>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> ---
>  drivers/mmc/host/sdhci-of-aspeed.c | 3 ---
>  1 file changed, 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
> index d5acb5afc50f..a9175ca85696 100644
> --- a/drivers/mmc/host/sdhci-of-aspeed.c
> +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> @@ -55,9 +55,6 @@ static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
>         int div;
>         u16 clk;
>
> -       if (clock == host->clock)
> -               return;
> -
>         sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
>
>         if (clock == 0)
> --
> 2.20.1
>

Further down in aspeed_sdhci_set_clock() you should probably also
remove the assignment of host->clock = clock, as that is already
managed by sdhci_set_ios().

Kind regards
Uffe

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Re: [PATCH 1/2] mmc: sdhci-of-aspeed: Uphold clocks-on post-condition of set_clock()

[Andrew Jeffery]

On Fri, 30 Aug 2019, at 17:31, Ulf Hansson wrote:
> On Fri, 30 Aug 2019 at 09:46, Andrew Jeffery <andrew@aj.id.au> wrote:
> >
> > The early-exit didn't seem to matter on the AST2500, but on the AST2600
> > the SD clock genuinely may not be running on entry to
> > aspeed_sdhci_set_clock(). Remove the early exit to ensure we always run
> > sdhci_enable_clk().
> >
> > Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> > ---
> >  drivers/mmc/host/sdhci-of-aspeed.c | 3 ---
> >  1 file changed, 3 deletions(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
> > index d5acb5afc50f..a9175ca85696 100644
> > --- a/drivers/mmc/host/sdhci-of-aspeed.c
> > +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> > @@ -55,9 +55,6 @@ static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> >         int div;
> >         u16 clk;
> >
> > -       if (clock == host->clock)
> > -               return;
> > -
> >         sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> >
> >         if (clock == 0)
> > --
> > 2.20.1
> >
> 
> Further down in aspeed_sdhci_set_clock() you should probably also
> remove the assignment of host->clock = clock, as that is already
> managed by sdhci_set_ios().

Ah, I'll fix that in a v2 once I have your thoughts on patch 2/2.

Thanks for the lightning quick feedback!

Andrew

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Re: [PATCH 1/2] mmc: sdhci-of-aspeed: Uphold clocks-on post-condition of set_clock()

[Ulf Hansson]

On Fri, 30 Aug 2019 at 10:07, Andrew Jeffery <andrew@aj.id.au> wrote:
>
>
>
> On Fri, 30 Aug 2019, at 17:31, Ulf Hansson wrote:
> > On Fri, 30 Aug 2019 at 09:46, Andrew Jeffery <andrew@aj.id.au> wrote:
> > >
> > > The early-exit didn't seem to matter on the AST2500, but on the AST2600
> > > the SD clock genuinely may not be running on entry to
> > > aspeed_sdhci_set_clock(). Remove the early exit to ensure we always run
> > > sdhci_enable_clk().
> > >
> > > Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> > > ---
> > >  drivers/mmc/host/sdhci-of-aspeed.c | 3 ---
> > >  1 file changed, 3 deletions(-)
> > >
> > > diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
> > > index d5acb5afc50f..a9175ca85696 100644
> > > --- a/drivers/mmc/host/sdhci-of-aspeed.c
> > > +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> > > @@ -55,9 +55,6 @@ static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> > >         int div;
> > >         u16 clk;
> > >
> > > -       if (clock == host->clock)
> > > -               return;
> > > -
> > >         sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> > >
> > >         if (clock == 0)
> > > --
> > > 2.20.1
> > >
> >
> > Further down in aspeed_sdhci_set_clock() you should probably also
> > remove the assignment of host->clock = clock, as that is already
> > managed by sdhci_set_ios().
>
> Ah, I'll fix that in a v2 once I have your thoughts on patch 2/2.

I leave this one to Adrian to comment on, as he knows this better than me.

[...]

Kind regards
Uffe

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[PATCH 2/2] mmc: sdhci-of-aspeed: Allow max-frequency limitation of SDCLK

[Andrew Jeffery]

Add a get_max_clock() handler to sdhci-of-aspeed to report f_max as the
maximum clock rate if it is set. This enables artificial limitation of
the bus speed via max-frequency in the devicetree for e.g. the AST2600
evaluation board where I am seeing errors at 200MHz.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
---
 drivers/mmc/host/sdhci-of-aspeed.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
index a9175ca85696..5cc00abcd71f 100644
--- a/drivers/mmc/host/sdhci-of-aspeed.c
+++ b/drivers/mmc/host/sdhci-of-aspeed.c
@@ -52,16 +52,24 @@ static void aspeed_sdc_configure_8bit_mode(struct aspeed_sdc *sdc,
 
 static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
 {
+	struct sdhci_pltfm_host *pltfm_host;
+	unsigned long parent;
 	int div;
 	u16 clk;
 
+	pltfm_host = sdhci_priv(host);
+	parent = clk_get_rate(pltfm_host->clk);
+
 	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
 
 	if (clock == 0)
 		goto out;
 
+	if (WARN_ON(clock > host->max_clk))
+		clock = host->max_clk;
+
 	for (div = 1; div < 256; div *= 2) {
-		if ((host->max_clk / div) <= clock)
+		if ((parent / div) <= clock)
 			break;
 	}
 	div >>= 1;
@@ -74,6 +82,14 @@ static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
 	host->clock = clock;
 }
 
+static unsigned int aspeed_sdhci_get_max_clock(struct sdhci_host *host)
+{
+	if (host->mmc->f_max)
+		return host->mmc->f_max;
+
+	return sdhci_pltfm_clk_get_max_clock(host);
+}
+
 static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
 {
 	struct sdhci_pltfm_host *pltfm_priv;
@@ -100,7 +116,7 @@ static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
 
 static const struct sdhci_ops aspeed_sdhci_ops = {
 	.set_clock = aspeed_sdhci_set_clock,
-	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
+	.get_max_clock = aspeed_sdhci_get_max_clock,
 	.set_bus_width = aspeed_sdhci_set_bus_width,
 	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
 	.reset = sdhci_reset,
-- 
2.20.1


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