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Commit 356ab1e4 authored by David Collins's avatar David Collins
Browse files

bif: bif-core: add support for BIF slave NVM read and write 



Add support for reading and writing the non-volatile memory (NVM)
of BIF slaves.

Change-Id: Ie422ec57327102584bab2b039a733505320b065b
Signed-off-by: default avatarDavid Collins <collinsd@codeaurora.org>
parent d53a2a36

Documentation/bif-framework.txt

+14 −0
Original line number Diff line number Diff line
@@ -302,6 +302,20 @@ int bif_slave_read(struct bif_slave *slave, u16 addr, u8 *buf, int len); 
int bif_slave_write(struct bif_slave *slave, u16 addr, u8 *buf, int len);





BIF slave non-volatile memory manipulation:

-------------------------------------------



int bif_slave_nvm_raw_read(struct bif_slave *slave, u16 offset, u8 *buf,

				int len);



int bif_slave_nvm_raw_write(struct bif_slave *slave, u16 offset, u8 *buf,

				int len);



Raw NVM writing may be needed in order to intialize the NVM BIF object list.

However, its use can be dangerous as it can overwrite existing objects in the

list and make the list unparsable.





Get or set the BIF bus state or period:

---------------------------------------

drivers/bif/bif-core.c

+181 −3
Original line number Diff line number Diff line
@@ -205,13 +205,14 @@ static void bif_print_slave_data(struct bif_slave_dev *sdev) 
	}



	if (sdev->nvm_function) {

		pr_debug("  NVM function: pointer=0x%04X, task=%d, wr_buf_size=%d, nvm_base=0x%04X, nvm_size=%d\n",

		pr_debug("  NVM function: pointer=0x%04X, task=%d, wr_buf_size=%d, nvm_base=0x%04X, nvm_size=%d, nvm_lock_offset=%d\n",

			sdev->nvm_function->nvm_pointer,

			sdev->nvm_function->slave_control_channel,

			(sdev->nvm_function->write_buffer_size

				? sdev->nvm_function->write_buffer_size : 0),

			sdev->nvm_function->nvm_base_address,

			sdev->nvm_function->nvm_size);

			sdev->nvm_function->nvm_size,

			sdev->nvm_function->nvm_lock_offset);

		if (sdev->nvm_function->object_count)

			pr_debug("  NVM objects:\n");

		i = 0;
@@ -704,6 +705,106 @@ static int _bif_disable_auto_task(struct bif_slave_dev *sdev, unsigned int task) 
	return rc;

}



/*

 * The MIPI-BIF spec does not define a maximum time in which an NVM write must

 * complete.  The following delay and recheck count therefore represent

 * arbitrary but reasonable values.

 */

#define NVM_WRITE_POLL_DELAY_MS		20

#define NVM_WRITE_MAX_POLL_COUNT	50



static int _bif_slave_nvm_raw_write(struct bif_slave_dev *sdev, u16 offset,

				u8 *buf, int len)

{

	int rc = 0;

	int write_len, poll_count, rc2;

	u8 write_buf[3];



	if (!sdev->nvm_function) {

		pr_err("BIF slave has no NVM function\n");

		return -ENODEV;

	} else if (offset + len > sdev->nvm_function->nvm_size) {

		pr_err("write offset + len = %d > NVM size = %d\n",

			offset + len, sdev->nvm_function->nvm_size);

		return -EINVAL;

	} else if (offset < sdev->nvm_function->nvm_lock_offset) {

		pr_err("write offset = %d < first writable offset = %d\n",

			offset, sdev->nvm_function->nvm_lock_offset);

		return -EINVAL;

	}



	rc = _bif_enable_auto_task(sdev,

			sdev->nvm_function->slave_control_channel);

	if (rc) {

		pr_err("Failed to enable NVM auto task, rc=%d\n", rc);

		return rc;

	}



	while (len > 0) {

		write_len = sdev->nvm_function->write_buffer_size;

		if (write_len == 0)

			write_len = 256;

		write_len = min(write_len, len);



		write_buf[0] = offset >> 8;

		write_buf[1] = offset;

		write_buf[2] = (write_len == 256) ? 0 : write_len;



		/* Write offset and size registers. */

		rc = _bif_slave_write(sdev, sdev->nvm_function->nvm_pointer + 6,

					write_buf, 3);

		if (rc) {

			pr_err("BIF slave write failed, rc=%d\n", rc);

			goto done;

		}



		/* Write to NVM write buffer registers. */

		rc = _bif_slave_write(sdev, sdev->nvm_function->nvm_pointer + 9,

					buf, write_len);

		if (rc) {

			pr_err("BIF slave write failed, rc=%d\n", rc);

			goto done;

		}



		/*

		 * Wait for completion of the NVM write which was auto-triggered

		 * by the register write of the last byte in the NVM write

		 * buffer.

		 */

		poll_count = NVM_WRITE_MAX_POLL_COUNT;

		do {

			msleep(NVM_WRITE_POLL_DELAY_MS);

			rc = _bif_task_is_busy(sdev,

				sdev->nvm_function->slave_control_channel);

			poll_count--;

		} while (rc > 0 && poll_count > 0);



		if (rc < 0) {

			pr_err("Failed to check task state, rc=%d", rc);

			goto done;

		} else if (rc > 0) {

			pr_err("BIF slave NVM write not completed after %d ms\n",

			    NVM_WRITE_POLL_DELAY_MS * NVM_WRITE_MAX_POLL_COUNT);

			rc = -ETIMEDOUT;

			goto done;

		}



		len -= write_len;

		offset += write_len;

		buf += write_len;

	}



done:

	rc2 = _bif_disable_auto_task(sdev,

			sdev->nvm_function->slave_control_channel);

	if (rc2) {

		pr_err("Failed to disable NVM auto task, rc=%d\n", rc2);

		return rc2;

	}



	return rc;

}



/* Takes a mutex if this consumer is not an exclusive bus user. */

static void bif_ctrl_lock(struct bif_ctrl *ctrl)

{
@@ -1658,6 +1759,74 @@ int bif_slave_write(struct bif_slave *slave, u16 addr, u8 *buf, int len) 
}

EXPORT_SYMBOL(bif_slave_write);



/**

 * bif_slave_nvm_raw_read() - read contiguous memory values from a BIF slave's

 *		non-volatile memory (NVM)

 * @slave:	BIF slave handle

 * @offset:	Offset from the beginning of BIF slave NVM to begin reading at

 * @buf:	Buffer to fill with memory values

 * @len:	Number of byte to read

 *

 * Returns 0 for success or errno if an error occurred.

 */

int bif_slave_nvm_raw_read(struct bif_slave *slave, u16 offset, u8 *buf,

				int len)

{

	if (IS_ERR_OR_NULL(slave)) {

		pr_err("Invalid slave pointer=%ld\n", PTR_ERR(slave));

		return -EINVAL;

	} else if (IS_ERR_OR_NULL(buf)) {

		pr_err("Invalid buffer pointer=%ld\n", PTR_ERR(buf));

		return -EINVAL;

	} else if (!slave->sdev->nvm_function) {

		pr_err("BIF slave has no NVM function\n");

		return -ENODEV;

	} else if (offset + len > slave->sdev->nvm_function->nvm_size) {

		pr_err("read offset + len = %d > NVM size = %d\n",

			offset + len, slave->sdev->nvm_function->nvm_size);

		return -EINVAL;

	}



	return bif_slave_read(slave,

		slave->sdev->nvm_function->nvm_base_address + offset, buf, len);

}

EXPORT_SYMBOL(bif_slave_nvm_raw_read);



/**

 * bif_slave_nvm_raw_write() - write contiguous memory values to a BIF slave's

 *		non-volatile memory (NVM)

 * @slave:	BIF slave handle

 * @offset:	Offset from the beginning of BIF slave NVM to begin writing at

 * @buf:	Buffer containing values to write

 * @len:	Number of byte to write

 *

 * Note that this function does *not* respect the MIPI-BIF object data

 * formatting specification.  It can cause corruption of the object data list

 * stored in NVM if used improperly.

 *

 * Returns 0 for success or errno if an error occurred.

 */

int bif_slave_nvm_raw_write(struct bif_slave *slave, u16 offset, u8 *buf,

				int len)

{

	int rc;



	if (IS_ERR_OR_NULL(slave)) {

		pr_err("Invalid slave pointer=%ld\n", PTR_ERR(slave));

		return -EINVAL;

	} else if (IS_ERR_OR_NULL(buf)) {

		pr_err("Invalid buffer pointer=%ld\n", PTR_ERR(buf));

		return -EINVAL;

	}



	bif_slave_ctrl_lock(slave);

	rc = _bif_slave_nvm_raw_write(slave->sdev, offset, buf, len);

	bif_slave_ctrl_unlock(slave);



	return rc;

}

EXPORT_SYMBOL(bif_slave_nvm_raw_write);



/**

 * bif_slave_is_present() - check if a slave is currently physically present

 *		in the system
@@ -2282,6 +2451,15 @@ static int bif_initialize_nvm_function(struct bif_slave_dev *sdev, 
	sdev->nvm_function->nvm_base_address		= buf[4] << 8 | buf[5];

	sdev->nvm_function->nvm_size			= buf[6] << 8 | buf[7];



	/* Read NVM lock offset */

	rc = _bif_slave_read(sdev, sdev->nvm_function->nvm_pointer, buf, 2);

	if (rc) {

		pr_err("Slave memory read failed, rc=%d\n", rc);

		return rc;

	}



	sdev->nvm_function->nvm_lock_offset		= buf[0] << 8 | buf[1];



	INIT_LIST_HEAD(&sdev->nvm_function->object_list);



	/* Read object list */

include/linux/bif/consumer.h

+15 −0
Original line number Diff line number Diff line
@@ -342,6 +342,8 @@ struct bif_object { 
 *				is used to denote a 256 byte buffer.

 * @nvm_base_address:		BIF slave address where NVM begins

 * @nvm_size:			NVM size in bytes

 * @nvm_lock_offset:		Offset from the beginning of NVM of the first

 *				writable address

 * @object_count:		Number of BIF objects read from NVM

 * @object_list:		List of BIF objects read from NVM

 */
@@ -351,6 +353,7 @@ struct bif_nvm_function { 
	u8			write_buffer_size;

	u16			nvm_base_address;

	u16			nvm_size;

	u16			nvm_lock_offset;

	int			object_count;

	struct list_head	object_list;

};
@@ -505,6 +508,11 @@ int bif_slave_find_function(struct bif_slave *slave, u8 function, u8 *version, 
int bif_slave_read(struct bif_slave *slave, u16 addr, u8 *buf, int len);

int bif_slave_write(struct bif_slave *slave, u16 addr, u8 *buf, int len);



int bif_slave_nvm_raw_read(struct bif_slave *slave, u16 offset, u8 *buf,

				int len);

int bif_slave_nvm_raw_write(struct bif_slave *slave, u16 offset, u8 *buf,

				int len);



int bif_slave_is_present(struct bif_slave *slave);



int bif_slave_is_selected(struct bif_slave *slave);
@@ -587,6 +595,13 @@ static inline int bif_slave_write(struct bif_slave *slave, u16 addr, u8 *buf, 
				int len)

{ return -EPERM; }



static inline int bif_slave_nvm_raw_read(struct bif_slave *slave, u16 offset,

				u8 *buf, int len)

{ return -EPERM; }

static inline int bif_slave_nvm_raw_write(struct bif_slave *slave, u16 offset,

				u8 *buf, int len)

{ return -EPERM; }



static inline int bif_slave_is_present(struct bif_slave *slave)

{ return -EPERM; }