Re: [patch 2.6.22-git5 1/4] MMC headers learn about SPI

[David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>]

On Thursday 26 July 2007, Pierre Ossman wrote:
> On Thu, 26 Jul 2007 09:55:22 -0700
> David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org> wrote:
> 
> > 
> > As explained in the comment:  this reduces the padding.
> > The previous way needed one word per bitfield; this way
> > they all fit into the same word...
> > 
> 
> Ah, didn't realize that. I blame the effect two weeks of
> vacation has on the brain. :) 
> 
> Perhaps shuffling them all to the end (before private) so
> that it is more clear that they are grouped because of padding issues? 

What I did was add a comment about the padding, then grouped
them all after the 'u32 ocr' to save a smidgeon more padding
(on 64bit machines).  Overall, there's more padding to remove.


> > I'm not sure what you mean here, but then my first cup of coffee is
> > still trying to do its work.  Are you saying you want me to
> > 
> >  - increase the padding again?
> >  - define an MMC_RSP_SPI_BUSY, and use that?
> > 
> > The former would bother me a bit, but I could understand if you wanted
> > it to be in a different patch.  The latter is no problem at all.
> > 
> 
> Well, both initially. But padding is a relevant concern, so I'm
> content with the latter. 

Did both.  See the appended patch.

- Dave

==========	CUT HERE
Teach the MMC/SD/SDIO system headers that some hosts use SPI mode

 - New host capabilities and status bits
    * MMC_CAP_SPI, with mmc_host_is_spi() test
    * mmc_host.use_spi_crc flag
 
 - SPI-specific declarations:
    * Response types, MMC_RSP_SPI_R*
    * Two SPI-only commands 
    * Status bits used native to SPI:  R1_SPI_*, R2_SPI_*

 - Fix a few (unrelated) whitespace bugs in the headers.

 - Reorder a few mmc_host fields, removing several bytes of padding

None of these changes affect current code.

Signed-off-by: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
---
 include/linux/mmc/core.h |   24 ++++++++++++++++++++++--
 include/linux/mmc/host.h |   16 +++++++++++-----
 include/linux/mmc/mmc.h  |   47 +++++++++++++++++++++++++++++++++++++++++------
 3 files changed, 74 insertions(+), 13 deletions(-)

--- g26.orig/include/linux/mmc/host.h	2007-07-26 13:06:47.000000000 -0700
+++ g26/include/linux/mmc/host.h	2007-07-26 13:06:59.000000000 -0700
@@ -90,6 +90,7 @@ struct mmc_host {
 #define MMC_CAP_BYTEBLOCK	(1 << 2)	/* Can do non-log2 block sizes */
 #define MMC_CAP_MMC_HIGHSPEED	(1 << 3)	/* Can do MMC high-speed timing */
 #define MMC_CAP_SD_HIGHSPEED	(1 << 4)	/* Can do SD high-speed timing */
+#define MMC_CAP_SPI		(1 << 5)	/* Talks only SPI protocols */
 
 	/* host specific block data */
 	unsigned int		max_seg_size;	/* see blk_queue_max_segment_size */
@@ -106,6 +107,14 @@ struct mmc_host {
 	struct mmc_ios		ios;		/* current io bus settings */
 	u32			ocr;		/* the current OCR setting */
 
+	/* group bitfields together to minimize padding */
+	unsigned int		use_spi_crc:1;
+	unsigned int		claimed:1;	/* host exclusively claimed */
+	unsigned int		bus_dead:1;	/* bus has been released */
+#ifdef CONFIG_MMC_DEBUG
+	unsigned int		removed:1;	/* host is being removed */
+#endif
+
 	unsigned int		mode;		/* current card mode of host */
 #define MMC_MODE_MMC		0
 #define MMC_MODE_SD		1
@@ -113,16 +122,11 @@ struct mmc_host {
 	struct mmc_card		*card;		/* device attached to this host */
 
 	wait_queue_head_t	wq;
-	unsigned int		claimed:1;	/* host exclusively claimed */
 
 	struct delayed_work	detect;
-#ifdef CONFIG_MMC_DEBUG
-	unsigned int		removed:1;	/* host is being removed */
-#endif
 
 	const struct mmc_bus_ops *bus_ops;	/* current bus driver */
 	unsigned int		bus_refs;	/* reference counter */
-	unsigned int		bus_dead:1;	/* bus has been released */
 
 	unsigned long		private[0] ____cacheline_aligned;
 };
@@ -137,6 +141,8 @@ static inline void *mmc_priv(struct mmc_
 	return (void *)host->private;
 }
 
+#define mmc_host_is_spi(host)	((host)->caps & MMC_CAP_SPI)
+
 #define mmc_dev(x)	((x)->parent)
 #define mmc_classdev(x)	(&(x)->class_dev)
 #define mmc_hostname(x)	((x)->class_dev.bus_id)
--- g26.orig/include/linux/mmc/core.h	2007-07-26 13:06:47.000000000 -0700
+++ g26/include/linux/mmc/core.h	2007-07-26 13:06:59.000000000 -0700
@@ -25,14 +25,20 @@ struct mmc_command {
 #define MMC_RSP_CRC	(1 << 2)		/* expect valid crc */
 #define MMC_RSP_BUSY	(1 << 3)		/* card may send busy */
 #define MMC_RSP_OPCODE	(1 << 4)		/* response contains opcode */
-#define MMC_CMD_MASK	(3 << 5)		/* command type */
+
+#define MMC_CMD_MASK	(3 << 5)		/* non-SPI command type */
 #define MMC_CMD_AC	(0 << 5)
 #define MMC_CMD_ADTC	(1 << 5)
 #define MMC_CMD_BC	(2 << 5)
 #define MMC_CMD_BCR	(3 << 5)
 
+#define MMC_RSP_SPI_S1	(1 << 7)		/* one status byte */
+#define MMC_RSP_SPI_S2	(1 << 8)		/* second status byte */
+#define MMC_RSP_SPI_B4	(1 << 9)		/* four data bytes */
+#define MMC_RSP_SPI_BUSY (1 << 10)		/* card may send busy */
+
 /*
- * These are the response types, and correspond to valid bit
+ * These are the native response types, and correspond to valid bit
  * patterns of the above flags.  One additional valid pattern
  * is all zeros, which means we don't expect a response.
  */
@@ -47,6 +53,20 @@ struct mmc_command {
 #define mmc_resp_type(cmd)	((cmd)->flags & (MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC|MMC_RSP_BUSY|MMC_RSP_OPCODE))
 
 /*
+ * These are the SPI response types for MMC and SD cards (not SDIO).
+ * Commands return R1, with maybe more info.  Zero is an error type;
+ * callers must always provide the appropriate MMC_RSP_SPI_Rx flags.
+ */
+#define MMC_RSP_SPI_R1	(MMC_RSP_SPI_S1)
+#define MMC_RSP_SPI_R1B	(MMC_RSP_SPI_S1|MMC_RSP_SPI_BUSY)
+#define MMC_RSP_SPI_R2	(MMC_RSP_SPI_S1|MMC_RSP_SPI_S2)
+#define MMC_RSP_SPI_R3	(MMC_RSP_SPI_S1|MMC_RSP_SPI_B4)
+#define MMC_RSP_SPI_R7	(MMC_RSP_SPI_S1|MMC_RSP_SPI_B4)
+
+#define mmc_spi_resp_type(cmd)	((cmd)->flags & \
+		(MMC_RSP_SPI_S1|MMC_RSP_SPI_BUSY|MMC_RSP_SPI_S2|MMC_RSP_SPI_B4))
+
+/*
  * These are the command types.
  */
 #define mmc_cmd_type(cmd)	((cmd)->flags & MMC_CMD_MASK)
--- g26.orig/include/linux/mmc/mmc.h	2007-07-26 13:06:47.000000000 -0700
+++ g26/include/linux/mmc/mmc.h	2007-07-26 13:06:59.000000000 -0700
@@ -27,7 +27,7 @@
 
 /* Standard MMC commands (4.1)           type  argument     response */
    /* class 1 */
-#define	MMC_GO_IDLE_STATE         0   /* bc                          */
+#define MMC_GO_IDLE_STATE         0   /* bc                          */
 #define MMC_SEND_OP_COND          1   /* bcr  [31:0] OCR         R3  */
 #define MMC_ALL_SEND_CID          2   /* bcr                     R2  */
 #define MMC_SET_RELATIVE_ADDR     3   /* ac   [31:16] RCA        R1  */
@@ -39,8 +39,10 @@
 #define MMC_SEND_CID             10   /* ac   [31:16] RCA        R2  */
 #define MMC_READ_DAT_UNTIL_STOP  11   /* adtc [31:0] dadr        R1  */
 #define MMC_STOP_TRANSMISSION    12   /* ac                      R1b */
-#define MMC_SEND_STATUS	         13   /* ac   [31:16] RCA        R1  */
+#define MMC_SEND_STATUS          13   /* ac   [31:16] RCA        R1  */
 #define MMC_GO_INACTIVE_STATE    15   /* ac   [31:16] RCA            */
+#define MMC_SPI_READ_OCR         58   /* spi                  spi_R3 */
+#define MMC_SPI_CRC_ON_OFF       59   /* spi  [0:0] flag      spi_R1 */
 
   /* class 2 */
 #define MMC_SET_BLOCKLEN         16   /* ac   [31:0] block len   R1  */
@@ -90,15 +92,15 @@
  */
 
 /*
-  MMC status in R1
+  MMC status in R1, for native mode (SPI bits are different)
   Type
-  	e : error bit
+	e : error bit
 	s : status bit
 	r : detected and set for the actual command response
 	x : detected and set during command execution. the host must poll
             the card by sending status command in order to read these bits.
   Clear condition
-  	a : according to the card state
+	a : according to the card state
 	b : always related to the previous command. Reception of
             a valid command will clear it (with a delay of one command)
 	c : clear by read
@@ -124,10 +126,42 @@
 #define R1_CARD_ECC_DISABLED	(1 << 14)	/* sx, a */
 #define R1_ERASE_RESET		(1 << 13)	/* sr, c */
 #define R1_STATUS(x)            (x & 0xFFFFE000)
-#define R1_CURRENT_STATE(x)    	((x & 0x00001E00) >> 9)	/* sx, b (4 bits) */
+#define R1_CURRENT_STATE(x)	((x & 0x00001E00) >> 9)	/* sx, b (4 bits) */
 #define R1_READY_FOR_DATA	(1 << 8)	/* sx, a */
 #define R1_APP_CMD		(1 << 5)	/* sr, c */
 
+/*
+ * MMC/SD in SPI mode reports R1 status always, and R2 for SEND_STATUS
+ * R1 is the low order byte; R2 is the next highest byte, when present.
+ */
+#define R1_SPI_IDLE		(1 << 0)
+#define R1_SPI_ERASE_RESET	(1 << 1)
+#define R1_SPI_ILLEGAL_COMMAND	(1 << 2)
+#define R1_SPI_COM_CRC		(1 << 3)
+#define R1_SPI_ERASE_SEQ	(1 << 4)
+#define R1_SPI_ADDRESS		(1 << 5)
+#define R1_SPI_PARAMETER	(1 << 6)
+/* R1 bit 7 is always zero */
+#define R2_SPI_CARD_LOCKED	(1 << 8)
+#define R2_SPI_WP_ERASE_SKIP	(1 << 9)	/* or lock/unlock fail */
+#define R2_SPI_LOCK_UNLOCK_FAIL	R2_SPI_WP_ERASE_SKIP
+#define R2_SPI_ERROR		(1 << 10)
+#define R2_SPI_CC_ERROR		(1 << 11)
+#define R2_SPI_CARD_ECC_ERROR	(1 << 12)
+#define R2_SPI_WP_VIOLATION	(1 << 13)
+#define R2_SPI_ERASE_PARAM	(1 << 14)
+#define R2_SPI_OUT_OF_RANGE	(1 << 15)	/* or CSD overwrite */
+#define R2_SPI_CSD_OVERWRITE	R2_SPI_OUT_OF_RANGE
+
+static inline int mmc_status_card_is_locked(struct mmc_host *host, u32 status)
+{
+	if (mmc_host_is_spi(host))
+		return status & R2_SPI_CARD_LOCKED;
+	else
+		return status & R1_CARD_IS_LOCKED;
+}
+
+
 /* These are unpacked versions of the actual responses */
 
 struct _mmc_csd {
@@ -182,6 +216,7 @@ struct _mmc_csd {
  */
 #define CCC_BASIC		(1<<0)	/* (0) Basic protocol functions */
 					/* (CMD0,1,2,3,4,7,9,10,12,13,15) */
+					/* (and for SPI, CMD58,59) */
 #define CCC_STREAM_READ		(1<<1)	/* (1) Stream read commands */
 					/* (CMD11) */
 #define CCC_BLOCK_READ		(1<<2)	/* (2) Block read commands */

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