On Tue, 12 Apr 2022 at 05:32, Lai Jason <jasonlai.genesyslogic@xxxxxxxxx> wrote: > > On Thu, Apr 7, 2022 at 11:01 PM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > > > On Thu, 7 Apr 2022 at 12:45, Lai Jason <jasonlai.genesyslogic@xxxxxxxxx> wrote: > > > > > > Hi Uffe, > > > > > > On Thu, Mar 24, 2022 at 12:16 AM Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: > > > > > > > > On Tue, 22 Feb 2022 at 04:40, Jason Lai <jasonlai.genesyslogic@xxxxxxxxx> wrote: > > > > > > > > > > From: Jason Lai <jason.lai@xxxxxxxxxxxxxxxxxxx> > > > > > > > > > > UHS-II card initialization flow is divided into 2 categories: PHY & Card. > > > > > Part 1 - PHY Initialization: > > > > > Every host controller may need their own avtivation operation to > > > > > establish LINK between controller and card. So we add a new member > > > > > function(uhs2_detect_init) in struct mmc_host_ops for host > > > > > controller use. > > > > > Part 2 - Card Initialization: > > > > > This part can be divided into 6 substeps. > > > > > 1. Send UHS-II CCMD DEVICE_INIT to card. > > > > > 2. Send UHS-II CCMD ENUMERATE to card. > > > > > 3. Send UHS-II Native Read CCMD to obtain capabilities in CFG_REG > > > > > of card. > > > > > 4. Host compares capabilities of host controller and card, then > > > > > write the negotiated values to Setting field in CFG_REG of card > > > > > through UHS-II Native Write CCMD. > > > > > 5. Switch host controller's clock to Range B if it is supported by > > > > > both host controller and card. > > > > > 6. Execute legacy SD initialization flow. > > > > > Part 3 - Provide a function to tranaform legacy SD command packet into > > > > > UHS-II SD-TRAN DCMD packet. > > > > > > > > > > Most of the code added above came from Intel's original patch[3]. > > > > > > > > > > [3] > > > > > https://patchwork.kernel.org/project/linux-mmc/patch/1419672479-30852-2- > > > > > git-send-email-yi.y.sun@xxxxxxxxx/ > > > > > > > > > > Signed-off-by: Jason Lai <jason.lai@xxxxxxxxxxxxxxxxxxx> > > > > > --- > > > > > drivers/mmc/core/sd_uhs2.c | 835 ++++++++++++++++++++++++++++++++++++- > > > > > 1 file changed, 817 insertions(+), 18 deletions(-) > > > > > > > > > > diff --git a/drivers/mmc/core/sd_uhs2.c b/drivers/mmc/core/sd_uhs2.c > > > > > index 800957f74632..f1e8e30301eb 100644 > > > > > --- a/drivers/mmc/core/sd_uhs2.c > > > > > +++ b/drivers/mmc/core/sd_uhs2.c > > > > > @@ -3,6 +3,7 @@ > > > > > * Copyright (C) 2021 Linaro Ltd > > > > > * > > > > > * Author: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > > > > > + * Author: Jason Lai <jason.lai@xxxxxxxxxxxxxxxxxxx> > > > > > * > > > > > * Support for SD UHS-II cards > > > > > */ > > > > > @@ -10,19 +11,31 @@ > > > > > > > > > > #include <linux/mmc/host.h> > > > > > #include <linux/mmc/card.h> > > > > > +#include <linux/mmc/mmc.h> > > > > > +#include <linux/mmc/sd_uhs2.h> > > > > > > > > > > #include "core.h" > > > > > #include "bus.h" > > > > > +#include "card.h" > > > > > #include "sd.h" > > > > > +#include "sd_ops.h" > > > > > #include "mmc_ops.h" > > > > > +#include "sd_uhs2.h" > > > > > > > > > > static const unsigned int sd_uhs2_freqs[] = { 52000000, 26000000 }; > > > > > > > > > > static int sd_uhs2_set_ios(struct mmc_host *host) > > > > > { > > > > > struct mmc_ios *ios = &host->ios; > > > > > + int err = 0; > > > > > > > > > > - return host->ops->uhs2_set_ios(host, ios); > > > > > + pr_debug("%s: clock %uHz powermode %u Vdd %u timing %u\n", > > > > > + mmc_hostname(host), ios->clock, ios->power_mode, ios->vdd, > > > > > + ios->timing); > > > > > + > > > > > + host->ops->set_ios(host, ios); > > > > > > > > We discussed using the ->set_ios() callback in a previous version. To > > > > repeat myself, I don't think it's a good idea. UHS-II needs an > > > > entirely different power sequence than the legacy interface(s), hence > > > > I think it's simply cleaner to separate them. > > > > > > > > To move forward, I see two options. > > > > 1) Use only the ->uhs2_host_operation() ops. > > > > 2) Use a combination of the ->uhs2_set_ios() ops and the > > > > ->uhs2_host_operation() ops. > > > > > > > > > > I referred to the usage of "host->ops->set_ios" in core.c, it is called in > > > mmc_set_ios() and ".set_ios" is directed to sdhci_set_ios(), which is > > > located in mmc/host/sdhci.c. So I created sd_uhs2_set_ios() and call > > > host->ops->uhs2_set_ios() inside it. The ".uhs2_set_ios" is left to host > > > part to implement it. > > > > I see. In that case, what you are looking for is an sdhci specific > > callback, this wouldn't belong as part of the generic mmc host ops. > > > > That said, I still think we need to choose between the two options I > > suggested above. Otherwise, I fear that it will turn into a nightmare > > for the mmc host drivers to support both UHS-II and the legacy > > interface. > > > > In other words, I strongly suggest that we must not call ->set_ios() > > to manage the UHS-II interface. > > > > I will defer to you. But it's a bit complicated so I need more time to think > about how to organize these operations. Therefore, I'll submit PATCH V4 > before sd_uhs2_set_ios() being implemented. Okay. I will do my best to continue to provide guidance and review. Perhaps you could also have a closer look at the legacy code for eMMC/SD, to get some inspiration on how to structure the code in a consistent way. > > > > > > > > Both options work for me. However, perhaps if you could incorporate > > > > the changes done on the host driver at next submission, it becomes > > > > easier for me to understand what makes best sense. > > > > > > > > > + > > > > > + return err; > > > > > } > > > > > > > > > [...] > > > > > > > static int sd_uhs2_config_write(struct mmc_host *host, struct mmc_card *card) > > > > > { > > > > > + struct mmc_command cmd = {0}; > > > > > + struct uhs2_command uhs2_cmd = {}; > > > > > + u16 header = 0, arg = 0; > > > > > + u32 payload[2]; > > > > > + u8 nMinDataGap; > > > > > + u8 plen; > > > > > + int err; > > > > > + u8 resp[5] = {0}; > > > > > + u8 resp_len = 5; > > > > > + > > > > > + header = UHS2_NATIVE_PACKET | > > > > > + UHS2_PACKET_TYPE_CCMD | card->uhs2_config.node_id; > > > > > + arg = ((UHS2_DEV_CONFIG_GEN_SET & 0xFF) << 8) | > > > > > + UHS2_NATIVE_CMD_WRITE | > > > > > + UHS2_NATIVE_CMD_PLEN_8B | > > > > > + (UHS2_DEV_CONFIG_GEN_SET >> 8); > > > > > + > > > > > + if (card->uhs2_config.n_lanes == UHS2_DEV_CONFIG_2L_HD_FD && > > > > > + host->uhs2_caps.n_lanes == UHS2_DEV_CONFIG_2L_HD_FD) { > > > > > + /* Support HD */ > > > > > + host->uhs2_caps.flags |= MMC_UHS2_2L_HD; > > > > > > > > How is the uhs2_caps.flags field intended to be used? To me it looks > > > > like a way for the mmc core to exchange status/configuration > > > > information about the initialization process of the card, with the mmc > > > > host driver. Perhaps there is more too. Is that correct? > > > > > > > > If so, I think it looks quite similar for what we have in the struct > > > > mmc_ios, for the legacy interface(s). I am not saying we should use > > > > that, just trying to understand what would suit best here. > > > > > > > > > > The usage of uhs2_caps.flags is spread out through core and host. > > > All operations related to it cannot be integrated into uhs2_set_ios() > > > simply. I recommend maintaining the status quo. > > > > What is puzzling to me, is that the data is stored below uhs2_caps.* > > and that it's called "flags". It's not self-explanatory and it's not > > consistent with the way we use the ->set_ios() callback, for the > > legacy interface. > > > > Sorry, I did not understand why uhs2_caps.flag is related to set_ios(). > The bit flags are used to indicate current status of UHS2 card: > - bit 0: MMC_UHS2_SUPPORT > This flag indicates if current sd card supports UHS2 mode. By looking at the code, it seems like MMC_UHS2_SUPPORT is redundant, at least from the mmc core point of view. Everywhere it's used, we use MMC_UHS2_INITIALIZED too. Moreover, in patch 2 (mmc: core: Prepare to support SD UHS-II cards) I added MMC_CAP2_SD_UHS2 as a generic host cap, which is being used in mmc_attach_sd_uhs2(). This should be sufficient as a generic cap for UHS2, I think. > - bit 1: MMC_UHS2_INITIALIZED > This flag indicates if current uhs2 sd card had been initialized. In patch 2 (mmc: core: Prepare to support SD UHS-II cards), I added MMC_TIMING_SD_UHS2. It looks like it tries to serve a similar purpose. Moreover, I don't see where MMC_UHS2_INITIALIZED is getting set, but I assume it must be before we try to initialize the card by sending UHS2 specific commands to it, right? > - bit 2: MMC_UHS2_2L_HD > This flag indicates the speed mode of current uhs2 sd card is > 2L-HD mode. The host sets DCMD argument[0] bit 6 > according to this flag. That means this flag was checked in > every MMC request. If we compare how we managed things like this for the legacy interface, this information is kept in the "ios->timing" variable. > - bit 3: MMC_UHS2_APP_CMD > This flag indicates if the current SD_TRAN command is an APP > command. The host sets DCMD argument[0] bit 14 according to > this flag. That means this flag was checked in every MMC > request. Alright, so it's a specific flag for UHS2 commands. > - bit 4: MMC_UHS2_SPEED_B > This flag indicates the speed range of current UHS2 sd card. This > flag is used only during uhs2 sd card initialization. > > > It looks to me that we should rather add a new variable to the struct > > mmc_host and perhaps name it "uhs2_ios", to keep this data. Whether we > > need to create a new struct for "uhs2_ios" or if it's better to extend > > struct mmc_ios, I am not sure. I guess exploring this by writing the > > code would tell us what is best suited. > > > > I will add a new variable to the struct mmc_host and name it "uhs2_ios". > In UHS2 CCMD/DCMD command packet, DM in TMODE(bit 6 in Argument) > and bit APP(bit 15 in Argument) are set according to MMC_UHS2_2L_HD > and MMC_UHS2_APP_CMD. Hence, I plan to define struct uhs2_ios as: > struct sd_uhs2_ios { > bool is_2L_HD_mode; /* DM bit in TMODE in UHS2 DCDM > * > argument will be set to 1 when Seems reasonable. > * > this field is true. */ > bool is_APP_CMD; /* APP bit in UHS2 CCMD/DCDM > * > argument will be set to 1 when > * > this field is true. */ Sounds like this better belongs in the struct uhs2_command. > unsigned int power_delay_ms; /* waiting for stable power */ > }; > > As for MMC_UHS2_INITIALIZED and MMC_UHS2_SPEED_B, I plan to add a variable > in struct mmc_card and name it "uhs2_state", to keep current UHS2 card states. > struct mmc_card { > struct mmc_host *host; /* the host this device belongs to */ > [...] > struct sd_uhs2_config uhs2_config; /* SD UHS-II config */ > u8 uhs2_state; /* SD > UHS-II states */ > #define MMC_UHS2_INITIALIZED BIT(1) > #define MMC_UHS2_SPEED_B BIT(2) > [...] Please don't. If it's configurations of the card, the data belongs under struct sd_uhs2_config. If it's configuration of the host, the data typically belongs in the struct sd_uhs2_ios. MMC_UHS2_SPEED_B is typically a speed mode for UHS2. For the legacy interface in the struct mmc_ios, we have an "unsigned char timing" variable to keep things like these. We need something similar in the struct sd_uhs2_ios for this, I think. Maybe we should even turn the bool for "2L_HD_mode" into being part of this "timing" variable. When it comes to the MMC_UHS2_INITIALIZED, if I understand correctly, it means that we have managed to power on the phy and are about to start the communication with the card. We could use a "bool" in the struct sd_uhs2_ios, to indicate this. Another option may be to use and set "MMC_TIMING_SD_UHS2" as a default speed mode in the "timing" variable above. No matter what, it seems like MMC_TIMING_SD_UHS2 doesn't belong in the legacy ios->variable, as I suggested in patch2. > }; > > Kind regards, > Jason > [...] Kind regards Uffe
