On Fri, 30 Nov 2018 at 06:53, Faiz Abbas <faiz_abbas@xxxxxx> wrote: > > Hi Kishon, > > On 30/11/18 10:10 AM, Kishon Vijay Abraham I wrote: > > Hi Faiz, > > > > On 30/11/18 12:35 AM, 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> > >> --- > >> 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); > >> + } > > > > Can't we get thermal zone once during probe? > > > > Tuning is also (ideally) supposed to happen only once per enumeration. > Also it doesn't make sense to get a thermal zone for lower speed systems > that won't do tuning. Currently sdhci-omap calls pm_runtime_get_sync() during probe, and then keeps the host device runtime resumed until ->remove() is called on it. I assume you are going to change that, at some point!? In other words, what will happen to the host device when it becomes runtime suspended? Is re-tuning needed when it gets runtime resumed, which is the case for many other sdhci variants? Depending on the answer, you may want to fetch the thermal zone during probe. :-) Kind regards Uffe
