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Date: Fri, 7 May 2021 15:48:08 +0800
From: Shawn Lin <shawn.lin@...k-chips.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
Cc: shawn.lin@...k-chips.com, linux-mmc <linux-mmc@...r.kernel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Linus Walleij <linus.walleij@...aro.org>,
Wolfram Sang <wsa+renesas@...g-engineering.com>,
Avri Altman <avri.altman@....com>,
Masami Hiramatsu <masami.hiramatsu@...aro.org>,
linux-block <linux-block@...r.kernel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 09/11] mmc: core: Read the SD function extension registers
for power management
On 2021/5/7 15:27, Ulf Hansson wrote:
> On Fri, 7 May 2021 at 04:06, Shawn Lin <shawn.lin@...k-chips.com> wrote:
>>
>>
>> On 2021/5/5 0:12, Ulf Hansson wrote:
>>> In SD spec v4.x the SD function extension registers were introduced. A
>>
>> I have a v4.0 spec and it doesn't state that v4.0 suppports reading
>> extension registers but just says TBD instead. So I guess v4.x doesn't
>> include v4.0 ?
>
> Good question. The v4.0 spec introduces the CMD48/49 and CMD58/59,
> while in v4.10 the spec adds the power management extensions.
>
> I can update the commit message to better reflect this, if you prefer!?
It would be better.
And I downloaded the latest v8.00 spec, checked carefully with the new
features there to make sure we don't make any misinterpretations at
first.
For patch 9 -11 as well,
Reviewed-by: Shawn Lin <shawn.lin@...k-chips.con>
>
> Thanks a lot for reviewing!
>
> Kind regards
> Uffe
>
>>
>>> specific function register were added to let the card announce support for
>>> optional features in regards to power management. The features that were
>>> added are "Power Off Notification", "Power Down Mode" and "Power
>>> Sustenance".
>>>
>>> As a first step, let's read and parse this register for power management
>>> during the SD card initialization and store the information about the
>>> supported features in the struct mmc_card. In this way, we prepare for
>>> subsequent changes to implement the complete support for the new features.
>>>
>>> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
>>> ---
>>> drivers/mmc/core/sd.c | 178 +++++++++++++++++++++++++++++++++++++++
>>> include/linux/mmc/card.h | 13 +++
>>> include/linux/mmc/sd.h | 3 +
>>> 3 files changed, 194 insertions(+)
>>>
>>> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
>>> index de7b5f8df550..cb5e8b2fc32f 100644
>>> --- a/drivers/mmc/core/sd.c
>>> +++ b/drivers/mmc/core/sd.c
>>> @@ -996,6 +996,177 @@ static bool mmc_sd_card_using_v18(struct mmc_card *card)
>>> (SD_MODE_UHS_SDR50 | SD_MODE_UHS_SDR104 | SD_MODE_UHS_DDR50);
>>> }
>>>
>>> +static int sd_read_ext_reg(struct mmc_card *card, u8 fno, u8 page,
>>> + u16 offset, u16 len, u8 *reg_buf)
>>> +{
>>> + u32 cmd_args;
>>> +
>>> + /*
>>> + * Command arguments of CMD48:
>>> + * [31:31] MIO (0 = memory).
>>> + * [30:27] FNO (function number).
>>> + * [26:26] reserved (0).
>>> + * [25:18] page number.
>>> + * [17:9] offset address.
>>> + * [8:0] length (0 = 1 byte, 1ff = 512 bytes).
>>> + */
>>> + cmd_args = fno << 27 | page << 18 | offset << 9 | (len -1);
>>> +
>>> + return mmc_send_adtc_data(card, card->host, SD_READ_EXTR_SINGLE,
>>> + cmd_args, reg_buf, 512);
>>> +}
>>> +
>>> +static int sd_parse_ext_reg_power(struct mmc_card *card, u8 fno, u8 page,
>>> + u16 offset)
>>> +{
>>> + int err;
>>> + u8 *reg_buf;
>>> +
>>> + reg_buf = kzalloc(512, GFP_KERNEL);
>>> + if (!reg_buf)
>>> + return -ENOMEM;
>>> +
>>> + /* Read the extension register for power management function. */
>>> + err = sd_read_ext_reg(card, fno, page, offset, 512, reg_buf);
>>> + if (err) {
>>> + pr_warn("%s: error %d reading PM func of ext reg\n",
>>> + mmc_hostname(card->host), err);
>>> + goto out;
>>> + }
>>> +
>>> + /* PM revision consists of 4 bits. */
>>> + card->ext_power.rev = reg_buf[0] & 0xf;
>>> +
>>> + /* Power Off Notification support at bit 4. */
>>> + if (reg_buf[1] & 0x10)
>>> + card->ext_power.feature_support |= SD_EXT_POWER_OFF_NOTIFY;
>>> +
>>> + /* Power Sustenance support at bit 5. */
>>> + if (reg_buf[1] & 0x20)
>>> + card->ext_power.feature_support |= SD_EXT_POWER_SUSTENANCE;
>>> +
>>> + /* Power Down Mode support at bit 6. */
>>> + if (reg_buf[1] & 0x40)
>>> + card->ext_power.feature_support |= SD_EXT_POWER_DOWN_MODE;
>>> +
>>> + card->ext_power.fno = fno;
>>> + card->ext_power.page = page;
>>> + card->ext_power.offset = offset;
>>> +
>>> +out:
>>> + kfree(reg_buf);
>>> + return err;
>>> +}
>>> +
>>> +static int sd_parse_ext_reg(struct mmc_card *card, u8 *gen_info_buf,
>>> + u16 *next_ext_addr)
>>> +{
>>> + u8 num_regs, fno, page;
>>> + u16 sfc, offset, ext = *next_ext_addr;
>>> + u32 reg_addr;
>>> +
>>> + /*
>>> + * Parse only one register set per extension, as that is sufficient to
>>> + * support the standard functions. This means another 48 bytes in the
>>> + * buffer must be available.
>>> + */
>>> + if (ext + 48 > 512)
>>> + return -EFAULT;
>>> +
>>> + /* Standard Function Code */
>>> + memcpy(&sfc, &gen_info_buf[ext], 2);
>>> +
>>> + /* Address to the next extension. */
>>> + memcpy(next_ext_addr, &gen_info_buf[ext + 40], 2);
>>> +
>>> + /* Number of registers for this extension. */
>>> + num_regs = gen_info_buf[ext + 42];
>>> +
>>> + /* We support only one register per extension. */
>>> + if (num_regs != 1)
>>> + return 0;
>>> +
>>> + /* Extension register address. */
>>> + memcpy(®_addr, &gen_info_buf[ext + 44], 4);
>>> +
>>> + /* 9 bits (0 to 8) contains the offset address. */
>>> + offset = reg_addr & 0x1ff;
>>> +
>>> + /* 8 bits (9 to 16) contains the page number. */
>>> + page = reg_addr >> 9 & 0xff ;
>>> +
>>> + /* 4 bits (18 to 21) contains the function number. */
>>> + fno = reg_addr >> 18 & 0xf;
>>> +
>>> + /* Standard Function Code for power management. */
>>> + if (sfc == 0x1)
>>> + return sd_parse_ext_reg_power(card, fno, page, offset);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int sd_read_ext_regs(struct mmc_card *card)
>>> +{
>>> + int err, i;
>>> + u8 num_ext, *gen_info_buf;
>>> + u16 rev, len, next_ext_addr;
>>> +
>>> + if (mmc_host_is_spi(card->host))
>>> + return 0;
>>> +
>>> + if (!(card->scr.cmds & SD_SCR_CMD48_SUPPORT))
>>> + return 0;
>>> +
>>> + gen_info_buf = kzalloc(512, GFP_KERNEL);
>>> + if (!gen_info_buf)
>>> + return -ENOMEM;
>>> +
>>> + /*
>>> + * Read 512 bytes of general info, which is found at function number 0,
>>> + * at page 0 and with no offset.
>>> + */
>>> + err = sd_read_ext_reg(card, 0, 0, 0, 512, gen_info_buf);
>>> + if (err) {
>>> + pr_warn("%s: error %d reading general info of SD ext reg\n",
>>> + mmc_hostname(card->host), err);
>>> + goto out;
>>> + }
>>> +
>>> + /* General info structure revision. */
>>> + memcpy(&rev, &gen_info_buf[0], 2);
>>> +
>>> + /* Length of general info in bytes. */
>>> + memcpy(&len, &gen_info_buf[2], 2);
>>> +
>>> + /* Number of extensions to be find. */
>>> + num_ext = gen_info_buf[4];
>>> +
>>> + /* We support revision 0, but limit it to 512 bytes for simplicity. */
>>> + if (rev != 0 || len > 512) {
>>> + pr_warn("%s: non-supported SD ext reg layout\n",
>>> + mmc_hostname(card->host));
>>> + goto out;
>>> + }
>>> +
>>> + /*
>>> + * Parse the extension registers. The first extension should start
>>> + * immediately after the general info header (16 bytes).
>>> + */
>>> + next_ext_addr = 16;
>>> + for (i = 0; i < num_ext; i++) {
>>> + err = sd_parse_ext_reg(card, gen_info_buf, &next_ext_addr);
>>> + if (err) {
>>> + pr_warn("%s: error %d parsing SD ext reg\n",
>>> + mmc_hostname(card->host), err);
>>> + goto out;
>>> + }
>>> + }
>>> +
>>> +out:
>>> + kfree(gen_info_buf);
>>> + return err;
>>> +}
>>> +
>>> /*
>>> * Handle the detection and initialisation of a card.
>>> *
>>> @@ -1144,6 +1315,13 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
>>> }
>>> }
>>>
>>> + if (!oldcard) {
>>> + /* Read/parse the extension registers. */
>>> + err = sd_read_ext_regs(card);
>>> + if (err)
>>> + goto free_card;
>>> + }
>>> +
>>> if (host->cqe_ops && !host->cqe_enabled) {
>>> err = host->cqe_ops->cqe_enable(host, card);
>>> if (!err) {
>>> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
>>> index 858fc4d11240..03a862e93594 100644
>>> --- a/include/linux/mmc/card.h
>>> +++ b/include/linux/mmc/card.h
>>> @@ -191,6 +191,18 @@ struct sd_switch_caps {
>>> #define SD_MAX_CURRENT_800 (1 << SD_SET_CURRENT_LIMIT_800)
>>> };
>>>
>>> +struct sd_ext_reg {
>>> + u8 fno;
>>> + u8 page;
>>> + u16 offset;
>>> + u8 rev;
>>> + u8 feature_support;
>>> +/* Power Management Function. */
>>> +#define SD_EXT_POWER_OFF_NOTIFY (1<<0)
>>> +#define SD_EXT_POWER_SUSTENANCE (1<<1)
>>> +#define SD_EXT_POWER_DOWN_MODE (1<<2)
>>> +};
>>> +
>>> struct sdio_cccr {
>>> unsigned int sdio_vsn;
>>> unsigned int sd_vsn;
>>> @@ -292,6 +304,7 @@ struct mmc_card {
>>> struct sd_scr scr; /* extra SD information */
>>> struct sd_ssr ssr; /* yet more SD information */
>>> struct sd_switch_caps sw_caps; /* switch (CMD6) caps */
>>> + struct sd_ext_reg ext_power; /* SD extension reg for PM */
>>>
>>> unsigned int sdio_funcs; /* number of SDIO functions */
>>> atomic_t sdio_funcs_probed; /* number of probed SDIO funcs */
>>> diff --git a/include/linux/mmc/sd.h b/include/linux/mmc/sd.h
>>> index 2236aa540faa..43bfc5c39ad4 100644
>>> --- a/include/linux/mmc/sd.h
>>> +++ b/include/linux/mmc/sd.h
>>> @@ -29,6 +29,9 @@
>>> #define SD_APP_OP_COND 41 /* bcr [31:0] OCR R3 */
>>> #define SD_APP_SEND_SCR 51 /* adtc R1 */
>>>
>>> + /* class 11 */
>>> +#define SD_READ_EXTR_SINGLE 48 /* adtc [31:0] R1 */
>>> +
>>> /* OCR bit definitions */
>>> #define SD_OCR_S18R (1 << 24) /* 1.8V switching request */
>>> #define SD_ROCR_S18A SD_OCR_S18R /* 1.8V switching accepted by card */
>>>
>>
>>
>
>
>
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