Hi Philip,
On Sun, Jan 02, 2011 at 08:45:10AM -0800, Philip Rakity wrote:
>
> mmc->caps MMC_CAP_1_8V_DDR is set by looking at cabability_1
> register if sd 3.0 controller.
>
> Support for dual data rate (DDR50) with 1_8V signalling added
> with optional call back to enable external control of signalling
> voltage.
>
> no support for 1.2V core voltage since SD 3.0 does not support
> this.
>
> **** QUESTION ****
> should this be part of regulator framework ?
>
> delay for signaling voltage to settle set to 5ms (per spec).
>
> this code does not change the voltage supplied to the card.
> It assumes that this is correctly handled in the core/ layer.
>
> There is no requirement that the card voltage be at 1.8v
> for DDR to work. This violates DDR specification for
> SD Host Controller 3.0 since explicitly states card voltage
> is 3.3v while signalling voltage is set to 1.8v.
>
> tested on mmp2 -- brownstone -- under linux-next.
>
> Note: this board design runs a fixed voltage to the card and
> signaling voltage cannot be changed.
>
> Signed-off-by: Philip Rakity <prakity@xxxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci.c | 53 ++++++++++++++++++++++++++++++++++++++++++---
> drivers/mmc/host/sdhci.h | 5 ++++
> 2 files changed, 54 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index d5febe5..805f850 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -84,6 +84,8 @@ static void sdhci_dumpregs(struct sdhci_host *host)
> printk(KERN_DEBUG DRIVER_NAME ": Cmd: 0x%08x | Max curr: 0x%08x\n",
> sdhci_readw(host, SDHCI_COMMAND),
> sdhci_readl(host, SDHCI_MAX_CURRENT));
> + printk(KERN_DEBUG DRIVER_NAME ": HostCtrl2:0x%08x\n",
> + sdhci_readw(host, SDHCI_HOST_CONTROL_2));
>
> if (host->flags & SDHCI_USE_ADMA)
> printk(KERN_DEBUG DRIVER_NAME ": ADMA Err: 0x%08x | ADMA Ptr: 0x%08x\n",
> @@ -986,6 +988,38 @@ static void sdhci_finish_command(struct sdhci_host *host)
> host->cmd = NULL;
> }
>
> +/*
> + * Handle 1.8V signaling for DDR. No need to check for other
> + * DDR values since driver supports ONLY 1_8V DDR. This is
> + * set by the MMC_CAP_1_8V_DDR. 1_2V DDR is not supported.
> + */
> +static void sdhci_set_ddr(struct sdhci_host *host, unsigned int ddr)
> +{
> + u16 con;
> +
> + if (ddr == MMC_SDR_MODE)
> + return;
> +
> + con = sdhci_readw(host, SDHCI_HOST_CONTROL_2);
> + con |= SDCTRL_2_SDH_V18_EN;
> + sdhci_writew(host, con, SDHCI_HOST_CONTROL_2);
> +
> + /* Change sigalling voltage and wait for it to be stable */
signaling
> + if (host->ops->set_signaling_voltage)
> + host->ops->set_signaling_voltage(host, 18);
What do you think about passing the ddr mode itself (MMC_1_8V_DDR_MODE)
and having set_signaling_voltage() work out what voltage it needs to use
to achieve that? I don't like passing the raw number around so much.
> + else
> + mdelay(5);
> +
> + /*
> + * We can fail here but there is no higher level recovery
> + * since the card is already past the switch to ddr
> + */
> + con = sdhci_readw(host, SDHCI_HOST_CONTROL_2);
> + con &= ~SDCTRL_2_UHS_MODE_MASK;
> + con |= SDCTRL_2_UHS_MODE_SEL_DDR50;
> + sdhci_writew(host, con, SDHCI_HOST_CONTROL_2);
> +}
> +
> static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> {
> int div;
> @@ -1180,6 +1214,7 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> }
>
> sdhci_set_clock(host, ios->clock);
> + sdhci_set_ddr(host, ios->ddr);
>
> if (ios->power_mode == MMC_POWER_OFF)
> sdhci_set_power(host, -1);
> @@ -1744,7 +1779,7 @@ EXPORT_SYMBOL_GPL(sdhci_alloc_host);
> int sdhci_add_host(struct sdhci_host *host)
> {
> struct mmc_host *mmc;
> - unsigned int caps, ocr_avail;
> + unsigned int caps, caps_h, ocr_avail;
Maybe choose a more understandable name for caps_h?
> int ret;
>
> WARN_ON(host == NULL);
> @@ -1767,8 +1802,19 @@ int sdhci_add_host(struct sdhci_host *host)
> host->version);
> }
>
> - caps = (host->quirks & SDHCI_QUIRK_MISSING_CAPS) ? host->caps :
> - sdhci_readl(host, SDHCI_CAPABILITIES);
> + if (host->quirks & SDHCI_QUIRK_MISSING_CAPS) {
> + caps = host->caps;
> + caps_h = 0;
> + } else {
> + caps = sdhci_readl(host, SDHCI_CAPABILITIES);
> + if (host->version >= SDHCI_SPEC_300)
> + caps_h = sdhci_readl(host, SDHCI_CAPABILITIES_1);
> + else
> + caps_h = 0;
> + }
> +
> + if (caps_h & SDHCI_CAN_DDR50)
> + mmc->caps |= MMC_CAP_1_8V_DDR;
>
> if (host->quirks & SDHCI_QUIRK_FORCE_DMA)
> host->flags |= SDHCI_USE_SDMA;
> @@ -1905,7 +1951,6 @@ int sdhci_add_host(struct sdhci_host *host)
> ocr_avail |= MMC_VDD_29_30 | MMC_VDD_30_31;
> if (caps & SDHCI_CAN_VDD_180)
> ocr_avail |= MMC_VDD_165_195;
> -
> mmc->ocr_avail = ocr_avail;
> mmc->ocr_avail_sdio = ocr_avail;
> if (host->ocr_avail_sdio)
This whitespace change shouldn't be here.
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 36f3861..d976e4f 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -182,6 +182,9 @@
> #define SDHCI_CAN_64BIT 0x10000000
>
> #define SDHCI_CAPABILITIES_1 0x44
> +#define SDHCI_CAN_SDR50 0x00000001
> +#define SDHCI_CAN_SDR104 0x00000002
> +#define SDHCI_CAN_DDR50 0x00000004
>
You could use the BIT(0..2) macros here.
> #define SDHCI_MAX_CURRENT 0x48
>
> @@ -237,6 +240,8 @@ struct sdhci_ops {
> void (*platform_send_init_74_clocks)(struct sdhci_host *host,
> u8 power_mode);
> unsigned int (*get_ro)(struct sdhci_host *host);
> + unsigned int (*set_signaling_voltage)(struct sdhci_host *host,
> + unsigned short voltage);
> };
>
> #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
> --
Thanks,
--
Chris Ball <cjb@xxxxxxxxxx> <http://printf.net/>
One Laptop Per Child
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