| Message ID | 1407944656-14592-1-git-send-email-u.kleine-koenig@pengutronix.de |
|---|---|
| State | Superseded, archived |
| Headers | show |
Hello, On Wed, Aug 13, 2014 at 05:44:16PM +0200, Uwe Kleine-König wrote: > diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c > index f51b5ba3bbea..37ed493d8030 100644 > --- a/drivers/mmc/core/mmc_ops.c > +++ b/drivers/mmc/core/mmc_ops.c > @@ -93,6 +93,27 @@ int mmc_deselect_cards(struct mmc_host *host) > return _mmc_select_card(host, NULL); > } > > +/* > + * Write the value specified in the device tree or board code into the optional > + * 16 bit Driver Stage Register. This can be used to tune raise/fall times and > + * drive strength of the DAT and CMD outputs. The actual meaning of a given > + * value is hardware dependant. > + * The presence of the DSR register can be determined from the CSD register, > + * bit 76. > + */ > +int mmc_set_dsr(struct mmc_host *host) > +{ > + int err; The line declaring err can and should be dropped. I found that during my tests, but failed to change this in the patch before sending it out. If you consider applying my patch, please fix this up. If not I will take this as an opportunity to remind you in a few days with a v4 :-) Uwe > + struct mmc_command cmd = {0}; > + > + cmd.opcode = MMC_SET_DSR; > + > + cmd.arg = ((u32)host->dsr << 16) | 0xffff; > + cmd.flags = MMC_RSP_NONE | MMC_CMD_AC; > + > + return mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES); > +} > +
On 13 August 2014 17:44, Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote: > From: Sascha Hauer <s.hauer@pengutronix.de> > > Some (e)MMC and SD cards implement a DSR register that allows to tune > raise/fall times and drive strength of the CMD and DATA outputs. > The values to use depend on the card in use and the host. > It might be needed to reduce the drive strength to prevent voltage peaks > above the host's specification. > > Implement a 'dsr' devicetree property that allows to specify the value > to set the DSR to. For non-dt setups the new members of mmc_host can be > set by board code. > > This patch was initially authored by Sascha Hauer. It contains > improvements authored by Markus Niebel and Uwe Kleine-König. > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > Signed-off-by: Markus Niebel <Markus.Niebel@tq-group.com> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > Hello, > > earlier incarnations of this patch can be found at > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-July/272983.html > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/259281.html > > I need this functionallity on a machine where the default driver strength of > the eMMC chip is too big for the SoC. It seems to work without adapting the > drive strength, but the vendor reports that the DSR should be set to a certain > value to prevent poor signal integrity and increased wearout. > > Best regards > Uwe > > Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++ > drivers/mmc/core/host.c | 8 ++++++++ > drivers/mmc/core/mmc.c | 8 ++++++++ > drivers/mmc/core/mmc_ops.c | 21 +++++++++++++++++++++ > drivers/mmc/core/mmc_ops.h | 1 + > drivers/mmc/core/sd.c | 8 ++++++++ > include/linux/mmc/card.h | 3 ++- > include/linux/mmc/host.h | 3 +++ > 8 files changed, 53 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt > index 3c18001dfd5d..05bac770b4d0 100644 > --- a/Documentation/devicetree/bindings/mmc/mmc.txt > +++ b/Documentation/devicetree/bindings/mmc/mmc.txt > @@ -40,6 +40,8 @@ Optional properties: > - mmc-hs200-1_2v: eMMC HS200 mode(1.2V I/O) is supported > - mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported > - mmc-hs400-1_2v: eMMC HS400 mode(1.2V I/O) is supported > +- dsr: Value the card's (optional) Driver Stage Register (DSR) should be > + programmed with. Let's clarify that this is a 16 bit value. > > *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line > polarity properties, we have to fix the meaning of the "normal" and "inverted" > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c > index 95cceae96944..52e83f389428 100644 > --- a/drivers/mmc/core/host.c > +++ b/drivers/mmc/core/host.c > @@ -452,6 +452,14 @@ int mmc_of_parse(struct mmc_host *host) > if (of_find_property(np, "mmc-hs400-1_2v", &len)) > host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR; > > + if (of_find_property(np, "dsr", &len)) { > + u32 tmp; > + > + of_property_read_u32(np, "dsr", &tmp); > + host->dsr_req = 1; > + host->dsr = (u16)tmp; > + } > + Let's simplify the above with just: of_property_read_u16(np, "dsr", &host->dsr); > return 0; > > out: > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index 793c6f7ddb04..fdc1ac1360c4 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -162,6 +162,7 @@ static int mmc_decode_csd(struct mmc_card *card) > csd->read_partial = UNSTUFF_BITS(resp, 79, 1); > csd->write_misalign = UNSTUFF_BITS(resp, 78, 1); > csd->read_misalign = UNSTUFF_BITS(resp, 77, 1); > + csd->dsr_imp = UNSTUFF_BITS(resp, 76, 1); > csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3); > csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4); > csd->write_partial = UNSTUFF_BITS(resp, 21, 1); > @@ -1273,6 +1274,13 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, > } > > /* > + * handling only for cards supporting DSR and hosts requesting > + * DSR configuration > + */ > + if (card->csd.dsr_imp && host->dsr_req) We don't need host->dsr_req. Instead just check host->dsr. > + mmc_set_dsr(host); > + > + /* > * Select card, as all following commands rely on that. > */ > if (!mmc_host_is_spi(host)) { > diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c > index f51b5ba3bbea..37ed493d8030 100644 > --- a/drivers/mmc/core/mmc_ops.c > +++ b/drivers/mmc/core/mmc_ops.c > @@ -93,6 +93,27 @@ int mmc_deselect_cards(struct mmc_host *host) > return _mmc_select_card(host, NULL); > } > > +/* > + * Write the value specified in the device tree or board code into the optional > + * 16 bit Driver Stage Register. This can be used to tune raise/fall times and > + * drive strength of the DAT and CMD outputs. The actual meaning of a given > + * value is hardware dependant. > + * The presence of the DSR register can be determined from the CSD register, > + * bit 76. > + */ > +int mmc_set_dsr(struct mmc_host *host) > +{ > + int err; > + struct mmc_command cmd = {0}; > + > + cmd.opcode = MMC_SET_DSR; > + > + cmd.arg = ((u32)host->dsr << 16) | 0xffff; > + cmd.flags = MMC_RSP_NONE | MMC_CMD_AC; > + > + return mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES); > +} > + > int mmc_go_idle(struct mmc_host *host) > { > int err; > diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h > index 80ae9f4e0293..390dac665b2a 100644 > --- a/drivers/mmc/core/mmc_ops.h > +++ b/drivers/mmc/core/mmc_ops.h > @@ -14,6 +14,7 @@ > > int mmc_select_card(struct mmc_card *card); > int mmc_deselect_cards(struct mmc_host *host); > +int mmc_set_dsr(struct mmc_host *host); > int mmc_go_idle(struct mmc_host *host); > int mmc_send_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr); > int mmc_all_send_cid(struct mmc_host *host, u32 *cid); > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > index 0c44510bf717..25913889cbaa 100644 > --- a/drivers/mmc/core/sd.c > +++ b/drivers/mmc/core/sd.c > @@ -127,6 +127,7 @@ static int mmc_decode_csd(struct mmc_card *card) > csd->read_partial = UNSTUFF_BITS(resp, 79, 1); > csd->write_misalign = UNSTUFF_BITS(resp, 78, 1); > csd->read_misalign = UNSTUFF_BITS(resp, 77, 1); > + csd->dsr_imp = UNSTUFF_BITS(resp, 76, 1); > csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3); > csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4); > csd->write_partial = UNSTUFF_BITS(resp, 21, 1); > @@ -954,6 +955,13 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr, > } > > /* > + * handling only for cards supporting DSR and hosts requesting > + * DSR configuration > + */ > + if (card->csd.dsr_imp && host->dsr_req) Check host->dsr instead. > + mmc_set_dsr(host); > + > + /* > * Select card, as all following commands rely on that. > */ > if (!mmc_host_is_spi(host)) { > diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h > index d424b9de3aff..680a7f0188bb 100644 > --- a/include/linux/mmc/card.h > +++ b/include/linux/mmc/card.h > @@ -42,7 +42,8 @@ struct mmc_csd { > unsigned int read_partial:1, > read_misalign:1, > write_partial:1, > - write_misalign:1; > + write_misalign:1, > + dsr_imp:1; > }; > > struct mmc_ext_csd { > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index 7960424d0bc0..9e9ad7b31bb9 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -319,6 +319,7 @@ struct mmc_host { > #ifdef CONFIG_MMC_DEBUG > unsigned int removed:1; /* host is being removed */ > #endif > + unsigned int dsr_req:1; /* DSR is requested for Host */ Remove dsr_req. > > int rescan_disable; /* disable card detection */ > int rescan_entered; /* used with nonremovable devices */ > @@ -365,6 +366,8 @@ struct mmc_host { > > unsigned int slotno; /* used for sdio acpi binding */ > > + u16 dsr; /* optional driver stage (dsr) value */ > + > unsigned long private[0] ____cacheline_aligned; > }; > > -- > 2.0.1 > Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hello Ulf, On Thu, Aug 14, 2014 at 11:26:28AM +0200, Ulf Hansson wrote: > On 13 August 2014 17:44, Uwe Kleine-König > <u.kleine-koenig@pengutronix.de> wrote: > > From: Sascha Hauer <s.hauer@pengutronix.de> > > > > Some (e)MMC and SD cards implement a DSR register that allows to tune > > raise/fall times and drive strength of the CMD and DATA outputs. > > The values to use depend on the card in use and the host. > > It might be needed to reduce the drive strength to prevent voltage peaks > > above the host's specification. > > > > Implement a 'dsr' devicetree property that allows to specify the value > > to set the DSR to. For non-dt setups the new members of mmc_host can be > > set by board code. > > > > This patch was initially authored by Sascha Hauer. It contains > > improvements authored by Markus Niebel and Uwe Kleine-König. > > > > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> > > Signed-off-by: Markus Niebel <Markus.Niebel@tq-group.com> > > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > > --- > > Hello, > > > > earlier incarnations of this patch can be found at > > > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-July/272983.html > > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/259281.html > > > > I need this functionallity on a machine where the default driver strength of > > the eMMC chip is too big for the SoC. It seems to work without adapting the > > drive strength, but the vendor reports that the DSR should be set to a certain > > value to prevent poor signal integrity and increased wearout. > > > > Best regards > > Uwe > > > > Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++ > > drivers/mmc/core/host.c | 8 ++++++++ > > drivers/mmc/core/mmc.c | 8 ++++++++ > > drivers/mmc/core/mmc_ops.c | 21 +++++++++++++++++++++ > > drivers/mmc/core/mmc_ops.h | 1 + > > drivers/mmc/core/sd.c | 8 ++++++++ > > include/linux/mmc/card.h | 3 ++- > > include/linux/mmc/host.h | 3 +++ > > 8 files changed, 53 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt > > index 3c18001dfd5d..05bac770b4d0 100644 > > --- a/Documentation/devicetree/bindings/mmc/mmc.txt > > +++ b/Documentation/devicetree/bindings/mmc/mmc.txt > > @@ -40,6 +40,8 @@ Optional properties: > > - mmc-hs200-1_2v: eMMC HS200 mode(1.2V I/O) is supported > > - mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported > > - mmc-hs400-1_2v: eMMC HS400 mode(1.2V I/O) is supported > > +- dsr: Value the card's (optional) Driver Stage Register (DSR) should be > > + programmed with. > > Let's clarify that this is a 16 bit value. ok. > > *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line > > polarity properties, we have to fix the meaning of the "normal" and "inverted" > > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c > > index 95cceae96944..52e83f389428 100644 > > --- a/drivers/mmc/core/host.c > > +++ b/drivers/mmc/core/host.c > > @@ -452,6 +452,14 @@ int mmc_of_parse(struct mmc_host *host) > > if (of_find_property(np, "mmc-hs400-1_2v", &len)) > > host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR; > > > > + if (of_find_property(np, "dsr", &len)) { > > + u32 tmp; > > + > > + of_property_read_u32(np, "dsr", &tmp); > > + host->dsr_req = 1; > > + host->dsr = (u16)tmp; > > + } > > + > > Let's simplify the above with just: > of_property_read_u16(np, "dsr", &host->dsr); ok. > > return 0; > > > > out: > > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > > index 793c6f7ddb04..fdc1ac1360c4 100644 > > --- a/drivers/mmc/core/mmc.c > > +++ b/drivers/mmc/core/mmc.c > > @@ -162,6 +162,7 @@ static int mmc_decode_csd(struct mmc_card *card) > > csd->read_partial = UNSTUFF_BITS(resp, 79, 1); > > csd->write_misalign = UNSTUFF_BITS(resp, 78, 1); > > csd->read_misalign = UNSTUFF_BITS(resp, 77, 1); > > + csd->dsr_imp = UNSTUFF_BITS(resp, 76, 1); > > csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3); > > csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4); > > csd->write_partial = UNSTUFF_BITS(resp, 21, 1); > > @@ -1273,6 +1274,13 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, > > } > > > > /* > > + * handling only for cards supporting DSR and hosts requesting > > + * DSR configuration > > + */ > > + if (card->csd.dsr_imp && host->dsr_req) > > We don't need host->dsr_req. Instead just check host->dsr. I think this doesn't work. What is your actual suggestion? if (card->csd.dsr_imp && host->dsr) ? The intended semantic is that if the device tree has: dsr = <$somevalue>; the DSR is written, and if there is no such property, DSR is unhandled. If you just check for host->dsr being != 0, how to differenciate between dsr = <0>; in the device tree and dsr not being specified? Best regards Uwe
On 14 August 2014 11:49, Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote: > Hello Ulf, > > On Thu, Aug 14, 2014 at 11:26:28AM +0200, Ulf Hansson wrote: >> On 13 August 2014 17:44, Uwe Kleine-König >> <u.kleine-koenig@pengutronix.de> wrote: >> > From: Sascha Hauer <s.hauer@pengutronix.de> >> > >> > Some (e)MMC and SD cards implement a DSR register that allows to tune >> > raise/fall times and drive strength of the CMD and DATA outputs. >> > The values to use depend on the card in use and the host. >> > It might be needed to reduce the drive strength to prevent voltage peaks >> > above the host's specification. >> > >> > Implement a 'dsr' devicetree property that allows to specify the value >> > to set the DSR to. For non-dt setups the new members of mmc_host can be >> > set by board code. >> > >> > This patch was initially authored by Sascha Hauer. It contains >> > improvements authored by Markus Niebel and Uwe Kleine-König. >> > >> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> >> > Signed-off-by: Markus Niebel <Markus.Niebel@tq-group.com> >> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> >> > --- >> > Hello, >> > >> > earlier incarnations of this patch can be found at >> > >> > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-July/272983.html >> > http://lists.infradead.org/pipermail/linux-arm-kernel/2014-May/259281.html >> > >> > I need this functionallity on a machine where the default driver strength of >> > the eMMC chip is too big for the SoC. It seems to work without adapting the >> > drive strength, but the vendor reports that the DSR should be set to a certain >> > value to prevent poor signal integrity and increased wearout. >> > >> > Best regards >> > Uwe >> > >> > Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++ >> > drivers/mmc/core/host.c | 8 ++++++++ >> > drivers/mmc/core/mmc.c | 8 ++++++++ >> > drivers/mmc/core/mmc_ops.c | 21 +++++++++++++++++++++ >> > drivers/mmc/core/mmc_ops.h | 1 + >> > drivers/mmc/core/sd.c | 8 ++++++++ >> > include/linux/mmc/card.h | 3 ++- >> > include/linux/mmc/host.h | 3 +++ >> > 8 files changed, 53 insertions(+), 1 deletion(-) >> > >> > diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt >> > index 3c18001dfd5d..05bac770b4d0 100644 >> > --- a/Documentation/devicetree/bindings/mmc/mmc.txt >> > +++ b/Documentation/devicetree/bindings/mmc/mmc.txt >> > @@ -40,6 +40,8 @@ Optional properties: >> > - mmc-hs200-1_2v: eMMC HS200 mode(1.2V I/O) is supported >> > - mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported >> > - mmc-hs400-1_2v: eMMC HS400 mode(1.2V I/O) is supported >> > +- dsr: Value the card's (optional) Driver Stage Register (DSR) should be >> > + programmed with. >> >> Let's clarify that this is a 16 bit value. > ok. > >> > *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line >> > polarity properties, we have to fix the meaning of the "normal" and "inverted" >> > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c >> > index 95cceae96944..52e83f389428 100644 >> > --- a/drivers/mmc/core/host.c >> > +++ b/drivers/mmc/core/host.c >> > @@ -452,6 +452,14 @@ int mmc_of_parse(struct mmc_host *host) >> > if (of_find_property(np, "mmc-hs400-1_2v", &len)) >> > host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR; >> > >> > + if (of_find_property(np, "dsr", &len)) { >> > + u32 tmp; >> > + >> > + of_property_read_u32(np, "dsr", &tmp); >> > + host->dsr_req = 1; >> > + host->dsr = (u16)tmp; >> > + } >> > + >> >> Let's simplify the above with just: >> of_property_read_u16(np, "dsr", &host->dsr); > ok. > >> > return 0; >> > >> > out: >> > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c >> > index 793c6f7ddb04..fdc1ac1360c4 100644 >> > --- a/drivers/mmc/core/mmc.c >> > +++ b/drivers/mmc/core/mmc.c >> > @@ -162,6 +162,7 @@ static int mmc_decode_csd(struct mmc_card *card) >> > csd->read_partial = UNSTUFF_BITS(resp, 79, 1); >> > csd->write_misalign = UNSTUFF_BITS(resp, 78, 1); >> > csd->read_misalign = UNSTUFF_BITS(resp, 77, 1); >> > + csd->dsr_imp = UNSTUFF_BITS(resp, 76, 1); >> > csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3); >> > csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4); >> > csd->write_partial = UNSTUFF_BITS(resp, 21, 1); >> > @@ -1273,6 +1274,13 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, >> > } >> > >> > /* >> > + * handling only for cards supporting DSR and hosts requesting >> > + * DSR configuration >> > + */ >> > + if (card->csd.dsr_imp && host->dsr_req) >> >> We don't need host->dsr_req. Instead just check host->dsr. > I think this doesn't work. What is your actual suggestion? > > if (card->csd.dsr_imp && host->dsr) > > ? The intended semantic is that if the device tree has: > > dsr = <$somevalue>; > > the DSR is written, and if there is no such property, DSR is unhandled. > If you just check for host->dsr being != 0, how to differenciate between > > dsr = <0>; I didn't think that was a valid mask? If so, you right! Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hello Ulf, On Thu, Aug 14, 2014 at 11:26:28AM +0200, Ulf Hansson wrote: > > diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c > > index 95cceae96944..52e83f389428 100644 > > --- a/drivers/mmc/core/host.c > > +++ b/drivers/mmc/core/host.c > > @@ -452,6 +452,14 @@ int mmc_of_parse(struct mmc_host *host) > > if (of_find_property(np, "mmc-hs400-1_2v", &len)) > > host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR; > > > > + if (of_find_property(np, "dsr", &len)) { > > + u32 tmp; > > + > > + of_property_read_u32(np, "dsr", &tmp); > > + host->dsr_req = 1; > > + host->dsr = (u16)tmp; > > + } > > + > > Let's simplify the above with just: > of_property_read_u16(np, "dsr", &host->dsr); The downside here is that the syntax changes when using of_property_read_u16. Instead of dsr = <0x100> the following must be written then: dsr = /bits/ 16 <0x100>; so I'd prefer to stay with of_property_read_u32. The block can still be simplified. Will fix that in v4. Best regards Uwe
diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt index 3c18001dfd5d..05bac770b4d0 100644 --- a/Documentation/devicetree/bindings/mmc/mmc.txt +++ b/Documentation/devicetree/bindings/mmc/mmc.txt @@ -40,6 +40,8 @@ Optional properties: - mmc-hs200-1_2v: eMMC HS200 mode(1.2V I/O) is supported - mmc-hs400-1_8v: eMMC HS400 mode(1.8V I/O) is supported - mmc-hs400-1_2v: eMMC HS400 mode(1.2V I/O) is supported +- dsr: Value the card's (optional) Driver Stage Register (DSR) should be + programmed with. *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line polarity properties, we have to fix the meaning of the "normal" and "inverted" diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 95cceae96944..52e83f389428 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -452,6 +452,14 @@ int mmc_of_parse(struct mmc_host *host) if (of_find_property(np, "mmc-hs400-1_2v", &len)) host->caps2 |= MMC_CAP2_HS400_1_2V | MMC_CAP2_HS200_1_2V_SDR; + if (of_find_property(np, "dsr", &len)) { + u32 tmp; + + of_property_read_u32(np, "dsr", &tmp); + host->dsr_req = 1; + host->dsr = (u16)tmp; + } + return 0; out: diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 793c6f7ddb04..fdc1ac1360c4 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -162,6 +162,7 @@ static int mmc_decode_csd(struct mmc_card *card) csd->read_partial = UNSTUFF_BITS(resp, 79, 1); csd->write_misalign = UNSTUFF_BITS(resp, 78, 1); csd->read_misalign = UNSTUFF_BITS(resp, 77, 1); + csd->dsr_imp = UNSTUFF_BITS(resp, 76, 1); csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3); csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4); csd->write_partial = UNSTUFF_BITS(resp, 21, 1); @@ -1273,6 +1274,13 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, } /* + * handling only for cards supporting DSR and hosts requesting + * DSR configuration + */ + if (card->csd.dsr_imp && host->dsr_req) + mmc_set_dsr(host); + + /* * Select card, as all following commands rely on that. */ if (!mmc_host_is_spi(host)) { diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c index f51b5ba3bbea..37ed493d8030 100644 --- a/drivers/mmc/core/mmc_ops.c +++ b/drivers/mmc/core/mmc_ops.c @@ -93,6 +93,27 @@ int mmc_deselect_cards(struct mmc_host *host) return _mmc_select_card(host, NULL); } +/* + * Write the value specified in the device tree or board code into the optional + * 16 bit Driver Stage Register. This can be used to tune raise/fall times and + * drive strength of the DAT and CMD outputs. The actual meaning of a given + * value is hardware dependant. + * The presence of the DSR register can be determined from the CSD register, + * bit 76. + */ +int mmc_set_dsr(struct mmc_host *host) +{ + int err; + struct mmc_command cmd = {0}; + + cmd.opcode = MMC_SET_DSR; + + cmd.arg = ((u32)host->dsr << 16) | 0xffff; + cmd.flags = MMC_RSP_NONE | MMC_CMD_AC; + + return mmc_wait_for_cmd(host, &cmd, MMC_CMD_RETRIES); +} + int mmc_go_idle(struct mmc_host *host) { int err; diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h index 80ae9f4e0293..390dac665b2a 100644 --- a/drivers/mmc/core/mmc_ops.h +++ b/drivers/mmc/core/mmc_ops.h @@ -14,6 +14,7 @@ int mmc_select_card(struct mmc_card *card); int mmc_deselect_cards(struct mmc_host *host); +int mmc_set_dsr(struct mmc_host *host); int mmc_go_idle(struct mmc_host *host); int mmc_send_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr); int mmc_all_send_cid(struct mmc_host *host, u32 *cid); diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index 0c44510bf717..25913889cbaa 100644 --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -127,6 +127,7 @@ static int mmc_decode_csd(struct mmc_card *card) csd->read_partial = UNSTUFF_BITS(resp, 79, 1); csd->write_misalign = UNSTUFF_BITS(resp, 78, 1); csd->read_misalign = UNSTUFF_BITS(resp, 77, 1); + csd->dsr_imp = UNSTUFF_BITS(resp, 76, 1); csd->r2w_factor = UNSTUFF_BITS(resp, 26, 3); csd->write_blkbits = UNSTUFF_BITS(resp, 22, 4); csd->write_partial = UNSTUFF_BITS(resp, 21, 1); @@ -954,6 +955,13 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr, } /* + * handling only for cards supporting DSR and hosts requesting + * DSR configuration + */ + if (card->csd.dsr_imp && host->dsr_req) + mmc_set_dsr(host); + + /* * Select card, as all following commands rely on that. */ if (!mmc_host_is_spi(host)) { diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h index d424b9de3aff..680a7f0188bb 100644 --- a/include/linux/mmc/card.h +++ b/include/linux/mmc/card.h @@ -42,7 +42,8 @@ struct mmc_csd { unsigned int read_partial:1, read_misalign:1, write_partial:1, - write_misalign:1; + write_misalign:1, + dsr_imp:1; }; struct mmc_ext_csd { diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 7960424d0bc0..9e9ad7b31bb9 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -319,6 +319,7 @@ struct mmc_host { #ifdef CONFIG_MMC_DEBUG unsigned int removed:1; /* host is being removed */ #endif + unsigned int dsr_req:1; /* DSR is requested for Host */ int rescan_disable; /* disable card detection */ int rescan_entered; /* used with nonremovable devices */ @@ -365,6 +366,8 @@ struct mmc_host { unsigned int slotno; /* used for sdio acpi binding */ + u16 dsr; /* optional driver stage (dsr) value */ + unsigned long private[0] ____cacheline_aligned; };