HSMMC IP on AM33xx need a special setting to handle High-speed cards.
Other platforms like TI81xx, OMAP4 may need this as-well. This depends
on the HSMMC IP timing closure done for the high speed cards.
From AM335x TRM (SPRUH73F - 18.3.12 Output Signals Generation)
The MMC/SD/SDIO output signals can be driven on either falling edge or
rising edge depending on the SD_HCTL[2] HSPE bit. This feature allows
to reach better timing performance, and thus to increase data transfer
frequency.
There are few pre-requisites for enabling the HSPE bit
- Controller should support High-Speed-Enable Bit and
- Controller should not be using DDR Mode and
- Controller should advertise that it supports High Speed in
capabilities register and
- MMC/SD clock coming out of controller > 25MHz
Note:
The implementation reuses the output of calc_divisor() so as to reduce
code addition.
Signed-off-by: Hebbar, Gururaja <gururaja.hebbar@xxxxxx>
---
Rebased on mmc-next (v3.7.0-rc1)
Only Build tested since EDMA support for AM335x is not yet added
Changes in V2
- Added note in commit message about code re-use
- replaced ((a & BIT(n) == BIT(n))) with (a & BIT(n)) since
effectively both are same.
:100644 100644 be76a23... ed271fc... M Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
:100644 100644 8b4e4f2... 346af5b... M arch/arm/plat-omap/include/plat/mmc.h
:100644 100644 54bfd0c... 5ea4c9d... M drivers/mmc/host/omap_hsmmc.c
.../devicetree/bindings/mmc/ti-omap-hsmmc.txt | 1 +
arch/arm/plat-omap/include/plat/mmc.h | 1 +
drivers/mmc/host/omap_hsmmc.c | 30 +++++++++++++++++++-
3 files changed, 31 insertions(+), 1 deletions(-)
diff --git a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
index be76a23..ed271fc 100644
--- a/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
+++ b/Documentation/devicetree/bindings/mmc/ti-omap-hsmmc.txt
@@ -19,6 +19,7 @@ ti,dual-volt: boolean, supports dual voltage cards
"supply-name" examples are "vmmc", "vmmc_aux" etc
ti,non-removable: non-removable slot (like eMMC)
ti,needs-special-reset: Requires a special softreset sequence
+ti,needs-special-hs-handling: HSMMC IP needs special setting for handling High Speed
Example:
mmc1: mmc@0x4809c000 {
diff --git a/arch/arm/plat-omap/include/plat/mmc.h b/arch/arm/plat-omap/include/plat/mmc.h
index 8b4e4f2..346af5b 100644
--- a/arch/arm/plat-omap/include/plat/mmc.h
+++ b/arch/arm/plat-omap/include/plat/mmc.h
@@ -126,6 +126,7 @@ struct omap_mmc_platform_data {
/* we can put the features above into this variable */
#define HSMMC_HAS_PBIAS (1 << 0)
#define HSMMC_HAS_UPDATED_RESET (1 << 1)
+#define HSMMC_HAS_HSPE_SUPPORT (1 << 2)
unsigned features;
int switch_pin; /* gpio (card detect) */
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 54bfd0c..5ea4c9d 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -62,6 +62,7 @@
#define VS18 (1 << 26)
#define VS30 (1 << 25)
+#define HSS (1 << 21)
#define SDVS18 (0x5 << 9)
#define SDVS30 (0x6 << 9)
#define SDVS33 (0x7 << 9)
@@ -89,6 +90,7 @@
#define MSBS (1 << 5)
#define BCE (1 << 1)
#define FOUR_BIT (1 << 1)
+#define HSPE (1 << 2)
#define DDR (1 << 19)
#define DW8 (1 << 5)
#define CC 0x1
@@ -489,6 +491,7 @@ static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
struct mmc_ios *ios = &host->mmc->ios;
unsigned long regval;
unsigned long timeout;
+ unsigned long clkdiv;
dev_vdbg(mmc_dev(host->mmc), "Set clock to %uHz\n", ios->clock);
@@ -496,7 +499,8 @@ static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
regval = OMAP_HSMMC_READ(host->base, SYSCTL);
regval = regval & ~(CLKD_MASK | DTO_MASK);
- regval = regval | (calc_divisor(host, ios) << 6) | (DTO << 16);
+ clkdiv = calc_divisor(host, ios);
+ regval = regval | (clkdiv << 6) | (DTO << 16);
OMAP_HSMMC_WRITE(host->base, SYSCTL, regval);
OMAP_HSMMC_WRITE(host->base, SYSCTL,
OMAP_HSMMC_READ(host->base, SYSCTL) | ICE);
@@ -507,6 +511,27 @@ static void omap_hsmmc_set_clock(struct omap_hsmmc_host *host)
&& time_before(jiffies, timeout))
cpu_relax();
+ /*
+ * Enable High-Speed Support
+ * Pre-Requisites
+ * - Controller should support High-Speed-Enable Bit
+ * - Controller should not be using DDR Mode
+ * - Controller should advertise that it supports High Speed
+ * in capabilities register
+ * - MMC/SD clock coming out of controller > 25MHz
+ */
+ if ((mmc_slot(host).features & HSMMC_HAS_HSPE_SUPPORT) &&
+ (ios->timing != MMC_TIMING_UHS_DDR50) &&
+ (OMAP_HSMMC_READ(host->base, CAPA) & HSS)) {
+ regval = OMAP_HSMMC_READ(host->base, HCTL);
+ if (clkdiv && (clk_get_rate(host->fclk)/clkdiv) > 25000000)
