On 29/11/18 9:05 PM, Faiz Abbas wrote: > Errata i929 in certain OMAP5/DRA7XX/AM57XX silicon revisions > (SPRZ426D - November 2014 - Revised February 2018 [1]) mentions > unexpected tuning pattern errors. A small failure band may be present > in the tuning range which may be missed by the current algorithm. > Furthermore, the failure bands vary with temperature leading to > different optimum tuning values for different temperatures. > > As suggested in the related Application Report (SPRACA9B - October 2017 > - Revised July 2018 [2]), tuning should be done in two stages. > In stage 1, assign the optimum ratio in the maximum pass window for the > current temperature. In stage 2, if the chosen value is close to the > small failure band, move away from it in the appropriate direction. > > References: > [1] http://www.ti.com/lit/pdf/sprz426 > [2] http://www.ti.com/lit/pdf/SPRACA9 > > Signed-off-by: Faiz Abbas <faiz_abbas@xxxxxx> Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx> > --- > drivers/mmc/host/Kconfig | 2 + > drivers/mmc/host/sdhci-omap.c | 90 ++++++++++++++++++++++++++++++++++- > 2 files changed, 91 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig > index 1b58739d9744..6d3553f06f27 100644 > --- a/drivers/mmc/host/Kconfig > +++ b/drivers/mmc/host/Kconfig > @@ -969,6 +969,8 @@ config MMC_SDHCI_XENON > config MMC_SDHCI_OMAP > tristate "TI SDHCI Controller Support" > depends on MMC_SDHCI_PLTFM && OF > + select THERMAL > + select TI_SOC_THERMAL > help > This selects the Secure Digital Host Controller Interface (SDHCI) > support present in TI's DRA7 SOCs. The controller supports > diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c > index b3cb39d0db6f..9ccce7ef3a60 100644 > --- a/drivers/mmc/host/sdhci-omap.c > +++ b/drivers/mmc/host/sdhci-omap.c > @@ -27,6 +27,7 @@ > #include <linux/regulator/consumer.h> > #include <linux/pinctrl/consumer.h> > #include <linux/sys_soc.h> > +#include <linux/thermal.h> > > #include "sdhci-pltfm.h" > > @@ -286,14 +287,18 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode) > struct sdhci_host *host = mmc_priv(mmc); > struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); > struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host); > + struct thermal_zone_device *thermal_dev; > struct device *dev = omap_host->dev; > struct mmc_ios *ios = &mmc->ios; > u32 start_window = 0, max_window = 0; > + bool single_point_failure = false; > u8 cur_match, prev_match = 0; > u32 length = 0, max_len = 0; > u32 phase_delay = 0; > + int temperature; > int ret = 0; > u32 reg; > + int i; > > /* clock tuning is not needed for upto 52MHz */ > if (ios->clock <= 52000000) > @@ -303,6 +308,16 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode) > if (ios->timing == MMC_TIMING_UHS_SDR50 && !(reg & CAPA2_TSDR50)) > return 0; > > + thermal_dev = thermal_zone_get_zone_by_name("cpu_thermal"); > + if (IS_ERR(thermal_dev)) { > + dev_err(dev, "Unable to get thermal zone for tuning\n"); > + return PTR_ERR(thermal_dev); > + } > + > + ret = thermal_zone_get_temp(thermal_dev, &temperature); > + if (ret) > + return ret; > + > reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_DLL); > reg |= DLL_SWT; > sdhci_omap_writel(omap_host, SDHCI_OMAP_DLL, reg); > @@ -317,6 +332,11 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode) > > omap_host->is_tuning = true; > > + /* > + * Stage 1: Search for a maximum pass window ignoring any > + * any single point failures. If the tuning value ends up > + * near it, move away from it in stage 2 below > + */ > while (phase_delay <= MAX_PHASE_DELAY) { > sdhci_omap_set_dll(omap_host, phase_delay); > > @@ -324,10 +344,15 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode) > if (cur_match) { > if (prev_match) { > length++; > + } else if (single_point_failure) { > + /* ignore single point failure */ > + length++; > } else { > start_window = phase_delay; > length = 1; > } > + } else { > + single_point_failure = prev_match; > } > > if (length > max_len) { > @@ -345,13 +370,76 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode) > goto tuning_error; > } > > + /* > + * Assign tuning value as a ratio of maximum pass window based > + * on temperature > + */ > + if (temperature < -20000) > + phase_delay = min(max_window + 4 * max_len - 24, > + max_window + > + DIV_ROUND_UP(13 * max_len, 16) * 4); > + else if (temperature < 20000) > + phase_delay = max_window + DIV_ROUND_UP(9 * max_len, 16) * 4; > + else if (temperature < 40000) > + phase_delay = max_window + DIV_ROUND_UP(8 * max_len, 16) * 4; > + else if (temperature < 70000) > + phase_delay = max_window + DIV_ROUND_UP(7 * max_len, 16) * 4; > + else if (temperature < 90000) > + phase_delay = max_window + DIV_ROUND_UP(5 * max_len, 16) * 4; > + else if (temperature < 120000) > + phase_delay = max_window + DIV_ROUND_UP(4 * max_len, 16) * 4; > + else > + phase_delay = max_window + DIV_ROUND_UP(3 * max_len, 16) * 4; > + > + /* > + * Stage 2: Search for a single point failure near the chosen tuning > + * value in two steps. First in the +3 to +10 range and then in the > + * +2 to -10 range. If found, move away from it in the appropriate > + * direction by the appropriate amount depending on the temperature. > + */ > + for (i = 3; i <= 10; i++) { > + sdhci_omap_set_dll(omap_host, phase_delay + i); > + > + if (mmc_send_tuning(mmc, opcode, NULL)) { > + if (temperature < 10000) > + phase_delay += i + 6; > + else if (temperature < 20000) > + phase_delay += i - 12; > + else if (temperature < 70000) > + phase_delay += i - 8; > + else > + phase_delay += i - 6; > + > + goto single_failure_found; > + } > + } > + > + for (i = 2; i >= -10; i--) { > + sdhci_omap_set_dll(omap_host, phase_delay + i); > + > + if (mmc_send_tuning(mmc, opcode, NULL)) { > + if (temperature < 10000) > + phase_delay += i + 12; > + else if (temperature < 20000) > + phase_delay += i + 8; > + else if (temperature < 70000) > + phase_delay += i + 8; > + else if (temperature < 90000) > + phase_delay += i + 10; > + else > + phase_delay += i + 12; > + > + goto single_failure_found; > + } > + } > + > +single_failure_found: > reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_AC12); > if (!(reg & AC12_SCLK_SEL)) { > ret = -EIO; > goto tuning_error; > } > > - phase_delay = max_window + 4 * (max_len >> 1); > sdhci_omap_set_dll(omap_host, phase_delay); > > omap_host->is_tuning = false; >
