[PATCH 0/4] mmc: core: Read/parse SD function extension registers

[PATCH 0/4] mmc: core: Read/parse SD function extension registers

[Ulf Hansson]

In the SD spec v4.x the SD function extension registers were introduced,
together with a new set of commands (CMD48/49 and CMD58/59) to read and write
to them.

Moreover, in v4.x a new standard function for power management features were
added, while in v6.x a new standard function for performance enhancements
features were added.

This series doesn't implement the complete support for any of the new
power/perf features, but starts out by reading and parsing the new registers
and stores the information in the struct mmc_card about what features the SD
card supports.

Note that, there are no HW updates need for the host to support reading/parsing
of the these new SD registers.

Tested with a 64GB Sandisk Extreme PRO UHS-I A2 card. Additional tests and
reviews are of course greatly appreciated.

Kind regards
Ulf Hansson


Ulf Hansson (4):
  mmc: core: Parse the SD SCR register for support of CMD48/49 and
    CMD58/59
  mmc: core: Prepare mmc_send_cxd_data() to be used for CMD48 for SD
    cards
  mmc: core: Read the SD function extension registers for power
    management
  mmc: core: Read performance enhancements registers for SD cards

 drivers/mmc/core/mmc_ops.c |  11 +-
 drivers/mmc/core/mmc_ops.h |   2 +
 drivers/mmc/core/sd.c      | 222 ++++++++++++++++++++++++++++++++++++-
 include/linux/mmc/card.h   |  21 ++++
 include/linux/mmc/sd.h     |   3 +
 5 files changed, 252 insertions(+), 7 deletions(-)

-- 
2.25.1

[PATCH 1/4] mmc: core: Parse the SD SCR register for support of CMD48/49 and CMD58/59

[Ulf Hansson]

In SD spec v4.x the support for CMD48/49 and CMD58/59 were introduced as
optional features. To let the card announce whether it supports the
commands, the SCR register has been extended with corresponding support
bits. Let's parse and store the information.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/core/sd.c    | 4 +++-
 include/linux/mmc/card.h | 2 ++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 2c48d6504101..de7b5f8df550 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -222,7 +222,9 @@ static int mmc_decode_scr(struct mmc_card *card)
 	else
 		card->erased_byte = 0x0;
 
-	if (scr->sda_spec3)
+	if (scr->sda_spec4)
+		scr->cmds = UNSTUFF_BITS(resp, 32, 4);
+	else if (scr->sda_spec3)
 		scr->cmds = UNSTUFF_BITS(resp, 32, 2);
 
 	/* SD Spec says: any SD Card shall set at least bits 0 and 2 */
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index f9ad35dd6012..858fc4d11240 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -139,6 +139,8 @@ struct sd_scr {
 	unsigned char		cmds;
 #define SD_SCR_CMD20_SUPPORT   (1<<0)
 #define SD_SCR_CMD23_SUPPORT   (1<<1)
+#define SD_SCR_CMD48_SUPPORT   (1<<2)
+#define SD_SCR_CMD58_SUPPORT   (1<<3)
 };
 
 struct sd_ssr {
-- 
2.25.1

[PATCH 2/4] mmc: core: Prepare mmc_send_cxd_data() to be used for CMD48 for SD cards

[Ulf Hansson]

The CMD48 is used to read the SD function extension registers, which is an
ADTC type of command with an R1 response. It's very similar to the commands
that are currently being managed via mmc_send_cxd_data().

Therefore, let's adapt mmc_send_cxd_data() so it can manage CMD48 as well.
While at it, let's also rename the function to mmc_send_adtc_data() as it
better describes its purpose.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/core/mmc_ops.c | 11 +++++------
 drivers/mmc/core/mmc_ops.h |  2 ++
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index aa6a85783723..148fdc528382 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -245,9 +245,8 @@ mmc_send_cxd_native(struct mmc_host *host, u32 arg, u32 *cxd, int opcode)
  * NOTE: void *buf, caller for the buf is required to use DMA-capable
  * buffer or on-stack buffer (with some overhead in callee).
  */
-static int
-mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
-		u32 opcode, void *buf, unsigned len)
+int mmc_send_adtc_data(struct mmc_card *card, struct mmc_host *host, u32 opcode,
+		       u32 args, void *buf, unsigned len)
 {
 	struct mmc_request mrq = {};
 	struct mmc_command cmd = {};
@@ -258,7 +257,7 @@ mmc_send_cxd_data(struct mmc_card *card, struct mmc_host *host,
 	mrq.data = &data;
 
 	cmd.opcode = opcode;
-	cmd.arg = 0;
+	cmd.arg = args;
 
 	/* NOTE HACK:  the MMC_RSP_SPI_R1 is always correct here, but we
 	 * rely on callers to never use this with "native" calls for reading
@@ -304,7 +303,7 @@ static int mmc_spi_send_cxd(struct mmc_host *host, u32 *cxd, u32 opcode)
 	if (!cxd_tmp)
 		return -ENOMEM;
 
-	ret = mmc_send_cxd_data(NULL, host, opcode, cxd_tmp, 16);
+	ret = mmc_send_adtc_data(NULL, host, opcode, 0, cxd_tmp, 16);
 	if (ret)
 		goto err;
 
@@ -352,7 +351,7 @@ int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd)
 	if (!ext_csd)
 		return -ENOMEM;
 
-	err = mmc_send_cxd_data(card, card->host, MMC_SEND_EXT_CSD, ext_csd,
+	err = mmc_send_adtc_data(card, card->host, MMC_SEND_EXT_CSD, 0, ext_csd,
 				512);
 	if (err)
 		kfree(ext_csd);
diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
index 5782fdf4e8e9..55b8ad1d004c 100644
--- a/drivers/mmc/core/mmc_ops.h
+++ b/drivers/mmc/core/mmc_ops.h
@@ -25,6 +25,8 @@ 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_set_relative_addr(struct mmc_card *card);
+int mmc_send_adtc_data(struct mmc_card *card, struct mmc_host *host, u32 opcode,
+		       u32 args, void *buf, unsigned len);
 int mmc_send_csd(struct mmc_card *card, u32 *csd);
 int __mmc_send_status(struct mmc_card *card, u32 *status, unsigned int retries);
 int mmc_send_status(struct mmc_card *card, u32 *status);
-- 
2.25.1

[PATCH 3/4] mmc: core: Read the SD function extension registers for power management

[Ulf Hansson]

In SD spec v4.x the SD function extension registers were introduced. A
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, it becomes easier
for subsequent changes to implement the complete support.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/core/sd.c    | 172 +++++++++++++++++++++++++++++++++++++++
 include/linux/mmc/card.h |  12 +++
 include/linux/mmc/sd.h   |   3 +
 3 files changed, 187 insertions(+)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index de7b5f8df550..d6e838b7c895 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -996,6 +996,171 @@ 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_fno(struct mmc_card *card, u8 fno, u32 reg_addr,
+			       u8 **buf)
+{
+	int err;
+	u8 *tmp_buf;
+	u32 cmd_args;
+
+	/*
+	 * Arguments of CMD48 to read a page of 512 bytes:
+	 * [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 (1FF = 512 bytes data).
+	 */
+	cmd_args = 0x000001ff | fno << 27 | reg_addr << 9;
+
+	tmp_buf = kzalloc(512, GFP_KERNEL);
+	if (!tmp_buf)
+		return -ENOMEM;
+
+	err = mmc_send_adtc_data(card, card->host, SD_READ_EXTR_SINGLE,
+				 cmd_args, tmp_buf, 512);
+	if (err)
+		kfree(tmp_buf);
+	else
+		*buf = tmp_buf;
+
+	return err;
+}
+
+static int sd_decode_ext_reg_power(struct mmc_card *card, u8 fno, u32 reg_addr)
+{
+	int err;
+	u8 *reg_buf;
+
+	/* Read the extension register for power management function. */
+	err = sd_read_ext_reg_fno(card, fno, reg_addr, &reg_buf);
+	if (err) {
+		pr_warn("%s: error %d reading PM func of ext reg\n",
+			mmc_hostname(card->host), err);
+		return err;
+	}
+
+	/* 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.reg_addr = reg_addr;
+	card->ext_power.fno = fno;
+
+	kfree(reg_buf);
+	return 0;
+}
+
+static int sd_decode_ext_reg(struct mmc_card *card, u8 *gen_info_buf,
+			     u16 *next_ext_addr)
+{
+	u8 num_reg_sets, fno;
+	u16 ext = *next_ext_addr, sfc;
+	u32 reg_set_addr, 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 sets for this extension. */
+	num_reg_sets = gen_info_buf[ext + 42];
+
+	if (num_reg_sets != 1)
+		return 0;
+
+	/* Extension register address. */
+	memcpy(&reg_set_addr, &gen_info_buf[ext + 44], 4);
+
+	/* First 17 bits contains the page and the offset. */
+	reg_addr = reg_set_addr & 0x1FFFF;
+
+	/* 4 bits (18 to 21) contains the Function Number. */
+	fno = reg_set_addr >> 18 & 0xf;
+
+	/* Standard Function Code for power management. */
+	if (sfc == 0x1)
+		return sd_decode_ext_reg_power(card, fno, reg_addr);
+
+	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;
+
+	/* Read general info at page 0, with no offset and FNO=0. */
+	err = sd_read_ext_reg_fno(card, 0, 0, &gen_info_buf);
+	if (err) {
+		pr_warn("%s: error %d reading general info of SD ext reg\n",
+			mmc_hostname(card->host), err);
+		return err;
+	}
+
+	/* 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;
+	}
+
+	/*
+	 * Read/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_decode_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 +1309,13 @@ 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..6a1d64fba0f3 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -191,6 +191,17 @@ struct sd_switch_caps {
 #define SD_MAX_CURRENT_800	(1 << SD_SET_CURRENT_LIMIT_800)
 };
 
+struct sd_ext_reg {
+	u32			reg_addr;
+	u8			fno;
+	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 +303,7 @@ 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 */
-- 
2.25.1

[PATCH 4/4] mmc: core: Read performance enhancements registers for SD cards

[Ulf Hansson]

In SD spec v6.x the SD function extension registers for performance
enhancements were introduced. These registers let the SD card announce
supports for various performance related features, like "self-maintenance",
"cache" and "command queuing".

Let's extend the parsing of SD function extension registers and store the
information in the struct mmc_card. This allows subsequent changes to
easier implement the complete support for new the performance enhancement
features.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---
 drivers/mmc/core/sd.c    | 46 ++++++++++++++++++++++++++++++++++++++++
 include/linux/mmc/card.h |  7 ++++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index d6e838b7c895..0e946afd6d22 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1063,6 +1063,48 @@ static int sd_decode_ext_reg_power(struct mmc_card *card, u8 fno, u32 reg_addr)
 	return 0;
 }
 
+static int sd_decode_ext_reg_perf(struct mmc_card *card, u8 fno, u32 reg_addr)
+{
+	int err;
+	u8 *reg_buf;
+
+	err = sd_read_ext_reg_fno(card, fno, reg_addr, &reg_buf);
+	if (err) {
+		pr_warn("%s: error %d reading PERF func of ext reg\n",
+			mmc_hostname(card->host), err);
+		return err;
+	}
+
+	/* PERF revision. */
+	card->ext_perf.rev = reg_buf[0];
+
+	/* FX_EVENT support at bit 0. */
+	if (reg_buf[1] & 0x1)
+		card->ext_perf.feature_support |= SD_EXT_PERF_FX_EVENT;
+
+	/* Card initiated self-maintenance support at bit 0. */
+	if (reg_buf[2] & 0x1)
+		card->ext_perf.feature_support |= SD_EXT_PERF_CARD_MAINT;
+
+	/* Host initiated self-maintenance support at bit 1. */
+	if (reg_buf[2] & 0x2)
+		card->ext_perf.feature_support |= SD_EXT_PERF_HOST_MAINT;
+
+	/* Cache support at bit 0. */
+	if (reg_buf[4] & 0x1)
+		card->ext_perf.feature_support |= SD_EXT_PERF_CACHE;
+
+	/* Command queue support indicated via queue depth bits (0 to 4). */
+	if (reg_buf[6] & 0x1f)
+		card->ext_perf.feature_support |= SD_EXT_PERF_CMD_QUEUE;
+
+	card->ext_perf.reg_addr = reg_addr;
+	card->ext_perf.fno = fno;
+
+	kfree(reg_buf);
+	return 0;
+}
+
 static int sd_decode_ext_reg(struct mmc_card *card, u8 *gen_info_buf,
 			     u16 *next_ext_addr)
 {
@@ -1103,6 +1145,10 @@ static int sd_decode_ext_reg(struct mmc_card *card, u8 *gen_info_buf,
 	if (sfc == 0x1)
 		return sd_decode_ext_reg_power(card, fno, reg_addr);
 
+	/* Standard Function Code for performance enhancement. */
+	if (sfc == 0x2)
+		return sd_decode_ext_reg_perf(card, fno, reg_addr);
+
 	return 0;
 }
 
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 6a1d64fba0f3..8e21eebe704d 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -200,6 +200,12 @@ struct sd_ext_reg {
 #define SD_EXT_POWER_OFF_NOTIFY	(1<<0)
 #define SD_EXT_POWER_SUSTENANCE	(1<<1)
 #define SD_EXT_POWER_DOWN_MODE	(1<<2)
+/* Performance Enhancement Function. */
+#define SD_EXT_PERF_FX_EVENT	(1<<0)
+#define SD_EXT_PERF_CARD_MAINT	(1<<1)
+#define SD_EXT_PERF_HOST_MAINT	(1<<2)
+#define SD_EXT_PERF_CACHE	(1<<3)
+#define SD_EXT_PERF_CMD_QUEUE	(1<<4)
 };
 
 struct sdio_cccr {
@@ -304,6 +310,7 @@ struct mmc_card {
 	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 */
+	struct sd_ext_reg	ext_perf;	/* SD extension reg for PERF */
 
 	unsigned int		sdio_funcs;	/* number of SDIO functions */
 	atomic_t		sdio_funcs_probed; /* number of probed SDIO funcs */
-- 
2.25.1