| Message ID | 20210121124052.3454-9-a-govindraju@ti.com |
|---|---|
| State | Changes Requested |
| Delegated to: | Lokesh Vutla |
| Headers | show |
| Series | Add support for MMC higher speed modes for TI's am65x, j721e and j7200 platforms | expand |
On 1/21/21 9:40 PM, Aswath Govindraju wrote: > From: Faiz Abbas <faiz_abbas@ti.com> > > With the new SW tuning App note[1], a custom tuning algorithm is > required for eMMC HS200, HS400 and SD card UHS modes. The algorithm > involves running through the 32 possible input tap delay values and > sending the appropriate tuning command (CMD19/21) for each of them > to get a fail or pass result for each of the values. Typically, the > range will have a small contiguous failing window. Considering the > tuning range as a circular buffer, the algorithm then sets a final > tuned value directly opposite to the failing window. > > [1] https://www.ti.com/lit/pdf/spract9 > > Signed-off-by: Faiz Abbas <faiz_abbas@ti.com> > Signed-off-by: Aswath Govindraju <a-govindraju@ti.com> Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com> Best Regards, Jaehoon Chung > --- > drivers/mmc/am654_sdhci.c | 45 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 45 insertions(+) > > diff --git a/drivers/mmc/am654_sdhci.c b/drivers/mmc/am654_sdhci.c > index e86ef1a8b218..9549420c6582 100644 > --- a/drivers/mmc/am654_sdhci.c > +++ b/drivers/mmc/am654_sdhci.c > @@ -9,6 +9,7 @@ > #include <common.h> > #include <dm.h> > #include <malloc.h> > +#include <mmc.h> > #include <power-domain.h> > #include <regmap.h> > #include <sdhci.h> > @@ -368,7 +369,48 @@ static int am654_sdhci_deferred_probe(struct sdhci_host *host) > return sdhci_probe(dev); > } > > +#ifdef MMC_SUPPORTS_TUNING > +#define ITAP_MAX 32 > +static int am654_sdhci_execute_tuning(struct mmc *mmc, u8 opcode) > +{ > + struct udevice *dev = mmc->dev; > + struct am654_sdhci_plat *plat = dev_get_plat(dev); > + int cur_val, prev_val = 1, fail_len = 0, pass_window = 0, pass_len; > + u32 itap; > + > + /* Enable ITAPDLY */ > + regmap_update_bits(plat->base, PHY_CTRL4, ITAPDLYENA_MASK, > + 1 << ITAPDLYENA_SHIFT); > + > + for (itap = 0; itap < ITAP_MAX; itap++) { > + am654_sdhci_write_itapdly(plat, itap); > + > + cur_val = !mmc_send_tuning(mmc, opcode, NULL); > + if (cur_val && !prev_val) > + pass_window = itap; > + > + if (!cur_val) > + fail_len++; > + > + prev_val = cur_val; > + } > + /* > + * Having determined the length of the failing window and start of > + * the passing window calculate the length of the passing window and > + * set the final value halfway through it considering the range as a > + * circular buffer > + */ > + pass_len = ITAP_MAX - fail_len; > + itap = (pass_window + (pass_len >> 1)) % ITAP_MAX; > + am654_sdhci_write_itapdly(plat, itap); > + > + return 0; > +} > +#endif > const struct sdhci_ops am654_sdhci_ops = { > +#ifdef MMC_SUPPORTS_TUNING > + .platform_execute_tuning = am654_sdhci_execute_tuning, > +#endif > .deferred_probe = am654_sdhci_deferred_probe, > .set_ios_post = &am654_sdhci_set_ios_post, > .set_control_reg = &am654_sdhci_set_control_reg, > @@ -408,6 +450,9 @@ static int j721e_4bit_sdhci_set_ios_post(struct sdhci_host *host) > } > > const struct sdhci_ops j721e_4bit_sdhci_ops = { > +#ifdef MMC_SUPPORTS_TUNING > + .platform_execute_tuning = am654_sdhci_execute_tuning, > +#endif > .deferred_probe = am654_sdhci_deferred_probe, > .set_ios_post = &j721e_4bit_sdhci_set_ios_post, > }; >
diff --git a/drivers/mmc/am654_sdhci.c b/drivers/mmc/am654_sdhci.c index e86ef1a8b218..9549420c6582 100644 --- a/drivers/mmc/am654_sdhci.c +++ b/drivers/mmc/am654_sdhci.c @@ -9,6 +9,7 @@ #include <common.h> #include <dm.h> #include <malloc.h> +#include <mmc.h> #include <power-domain.h> #include <regmap.h> #include <sdhci.h> @@ -368,7 +369,48 @@ static int am654_sdhci_deferred_probe(struct sdhci_host *host) return sdhci_probe(dev); } +#ifdef MMC_SUPPORTS_TUNING +#define ITAP_MAX 32 +static int am654_sdhci_execute_tuning(struct mmc *mmc, u8 opcode) +{ + struct udevice *dev = mmc->dev; + struct am654_sdhci_plat *plat = dev_get_plat(dev); + int cur_val, prev_val = 1, fail_len = 0, pass_window = 0, pass_len; + u32 itap; + + /* Enable ITAPDLY */ + regmap_update_bits(plat->base, PHY_CTRL4, ITAPDLYENA_MASK, + 1 << ITAPDLYENA_SHIFT); + + for (itap = 0; itap < ITAP_MAX; itap++) { + am654_sdhci_write_itapdly(plat, itap); + + cur_val = !mmc_send_tuning(mmc, opcode, NULL); + if (cur_val && !prev_val) + pass_window = itap; + + if (!cur_val) + fail_len++; + + prev_val = cur_val; + } + /* + * Having determined the length of the failing window and start of + * the passing window calculate the length of the passing window and + * set the final value halfway through it considering the range as a + * circular buffer + */ + pass_len = ITAP_MAX - fail_len; + itap = (pass_window + (pass_len >> 1)) % ITAP_MAX; + am654_sdhci_write_itapdly(plat, itap); + + return 0; +} +#endif const struct sdhci_ops am654_sdhci_ops = { +#ifdef MMC_SUPPORTS_TUNING + .platform_execute_tuning = am654_sdhci_execute_tuning, +#endif .deferred_probe = am654_sdhci_deferred_probe, .set_ios_post = &am654_sdhci_set_ios_post, .set_control_reg = &am654_sdhci_set_control_reg, @@ -408,6 +450,9 @@ static int j721e_4bit_sdhci_set_ios_post(struct sdhci_host *host) } const struct sdhci_ops j721e_4bit_sdhci_ops = { +#ifdef MMC_SUPPORTS_TUNING + .platform_execute_tuning = am654_sdhci_execute_tuning, +#endif .deferred_probe = am654_sdhci_deferred_probe, .set_ios_post = &j721e_4bit_sdhci_set_ios_post, };