| Message ID | 1529028255-6022-2-git-send-email-zhang.chunyan@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | mmc: add support for sdhci 4.0 | expand |
On 21/06/18 14:14, Chunyan Zhang wrote: > On 21 June 2018 at 18:49, Adrian Hunter <adrian.hunter@intel.com> wrote: >> On 15/06/18 05:04, Chunyan Zhang wrote: >>> For SD host controller version 4.00 or later ones, there're two >>> modes of implementation - Version 3.00 compatible mode or >>> Version 4 mode. This patch introduces a flag to record this. >>> >>> Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> >>> --- >>> drivers/mmc/host/sdhci.c | 6 ++++++ >>> drivers/mmc/host/sdhci.h | 6 ++++++ >>> 2 files changed, 12 insertions(+) >>> >>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c >>> index 2ededa7f..cf5695f 100644 >>> --- a/drivers/mmc/host/sdhci.c >>> +++ b/drivers/mmc/host/sdhci.c >>> @@ -3302,6 +3302,12 @@ void __sdhci_read_caps(struct sdhci_host *host, u16 *ver, u32 *caps, u32 *caps1) >>> v = ver ? *ver : sdhci_readw(host, SDHCI_HOST_VERSION); >>> host->version = (v & SDHCI_SPEC_VER_MASK) >> SDHCI_SPEC_VER_SHIFT; >>> >>> + if (host->version >= SDHCI_SPEC_400) { >>> + if (sdhci_readw(host, SDHCI_HOST_CONTROL2) & >>> + SDHCI_CTRL_V4_MODE) >>> + host->v4_mode = true; >>> + } >> >> At this point the host controller has just been reset which would mean it >> must be in version 3 compatibility mode, which would mean this code doesn't >> do anything. > > Why is it version 3 mode at this point? According to the specification, reset clears RW fields to zero. > > I've tested this code on the sd host controller which was introduced > in 6/7 in this patch-set, the result showed that it was v4_mode. > Moreover without this patch, the Spreadtrum's sdhci driver in patch > 6/7 couldn't work. > > Am I missing something here? It seems the Spreadtrum controller doesn't clear the "Host Version 4 Enable" bit upon software reset for all. Also this seems the wrong way around. The driver should decide whether or not to use V4 mode and then the "Host Version 4 Enable" bit should be set accordingly. V4 has been around so long that we can't just enable all supporting hardware without risking the possibility it will break some platform. So I suggest adding a function sdhci_enable_v4_mode() which is called during probe. > > Best, > Chunyan > >> >>> + >>> if (host->quirks & SDHCI_QUIRK_MISSING_CAPS) >>> return; >>> >>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h >>> index c95b0a4..128b0ba 100644 >>> --- a/drivers/mmc/host/sdhci.h >>> +++ b/drivers/mmc/host/sdhci.h >>> @@ -184,6 +184,7 @@ >>> #define SDHCI_CTRL_DRV_TYPE_D 0x0030 >>> #define SDHCI_CTRL_EXEC_TUNING 0x0040 >>> #define SDHCI_CTRL_TUNED_CLK 0x0080 >>> +#define SDHCI_CTRL_V4_MODE 0x1000 >>> #define SDHCI_CTRL_PRESET_VAL_ENABLE 0x8000 >>> >>> #define SDHCI_CAPABILITIES 0x40 >>> @@ -270,6 +271,8 @@ >>> #define SDHCI_SPEC_100 0 >>> #define SDHCI_SPEC_200 1 >>> #define SDHCI_SPEC_300 2 >>> +#define SDHCI_SPEC_400 3 >>> +#define SDHCI_SPEC_410 4 >>> >>> /* >>> * End of controller registers. >>> @@ -551,6 +554,9 @@ struct sdhci_host { >>> u32 sdma_boundary; >>> >>> unsigned long private[0] ____cacheline_aligned; >>> + >>> + /* Host Version 4 Enable */ >>> + bool v4_mode; >>> }; >>> >>> struct sdhci_ops { >>> >> >
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 2ededa7f..cf5695f 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -3302,6 +3302,12 @@ void __sdhci_read_caps(struct sdhci_host *host, u16 *ver, u32 *caps, u32 *caps1) v = ver ? *ver : sdhci_readw(host, SDHCI_HOST_VERSION); host->version = (v & SDHCI_SPEC_VER_MASK) >> SDHCI_SPEC_VER_SHIFT; + if (host->version >= SDHCI_SPEC_400) { + if (sdhci_readw(host, SDHCI_HOST_CONTROL2) & + SDHCI_CTRL_V4_MODE) + host->v4_mode = true; + } + if (host->quirks & SDHCI_QUIRK_MISSING_CAPS) return; diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index c95b0a4..128b0ba 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -184,6 +184,7 @@ #define SDHCI_CTRL_DRV_TYPE_D 0x0030 #define SDHCI_CTRL_EXEC_TUNING 0x0040 #define SDHCI_CTRL_TUNED_CLK 0x0080 +#define SDHCI_CTRL_V4_MODE 0x1000 #define SDHCI_CTRL_PRESET_VAL_ENABLE 0x8000 #define SDHCI_CAPABILITIES 0x40 @@ -270,6 +271,8 @@ #define SDHCI_SPEC_100 0 #define SDHCI_SPEC_200 1 #define SDHCI_SPEC_300 2 +#define SDHCI_SPEC_400 3 +#define SDHCI_SPEC_410 4 /* * End of controller registers. @@ -551,6 +554,9 @@ struct sdhci_host { u32 sdma_boundary; unsigned long private[0] ____cacheline_aligned; + + /* Host Version 4 Enable */ + bool v4_mode; }; struct sdhci_ops {
For SD host controller version 4.00 or later ones, there're two modes of implementation - Version 3.00 compatible mode or Version 4 mode. This patch introduces a flag to record this. Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org> --- drivers/mmc/host/sdhci.c | 6 ++++++ drivers/mmc/host/sdhci.h | 6 ++++++ 2 files changed, 12 insertions(+) -- 2.7.4