Commit d5812571 authored by Mario Limonciello's avatar Mario Limonciello Committed by Herbert Xu
Browse files

crypto: ccp - Add support for ringing a platform doorbell 

Some platforms support using a doorbell to communicate. Export
this feature for other drivers to utilize as well.

Link: https://lore.kernel.org/linux-i2c/20220916131854.687371-3-jsd@semihalf.com/


Suggested-by: default avatarJan Dabros <jsd@semihalf.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 22351239

drivers/crypto/ccp/platform-access.c

+66 −0
Original line number Diff line number Diff line
@@ -20,6 +20,14 @@ 


#define PSP_CMD_TIMEOUT_US	(500 * USEC_PER_MSEC)



/* Doorbell shouldn't be ringing */

static int check_doorbell(u32 __iomem *doorbell)

{

	u32 tmp;



	return readl_poll_timeout(doorbell, tmp, tmp != 0, 0, PSP_CMD_TIMEOUT_US);

}



/* Recovery field should be equal 0 to start sending commands */

static int check_recovery(u32 __iomem *cmd)

{
@@ -132,6 +140,62 @@ int psp_send_platform_access_msg(enum psp_platform_access_msg msg, 
}

EXPORT_SYMBOL_GPL(psp_send_platform_access_msg);



int psp_ring_platform_doorbell(int msg)

{

	struct psp_device *psp = psp_get_master_device();

	struct psp_platform_access_device *pa_dev;

	u32 __iomem *button, *cmd;

	int ret, val;



	if (!psp || !psp->platform_access_data)

		return -ENODEV;



	pa_dev = psp->platform_access_data;

	button = psp->io_regs + pa_dev->vdata->doorbell_button_reg;

	cmd = psp->io_regs + pa_dev->vdata->doorbell_cmd_reg;



	mutex_lock(&pa_dev->doorbell_mutex);



	if (check_doorbell(button)) {

		dev_dbg(psp->dev, "doorbell is not ready\n");

		ret = -EBUSY;

		goto unlock;

	}



	if (check_recovery(cmd)) {

		dev_dbg(psp->dev, "doorbell command in recovery\n");

		ret = -EBUSY;

		goto unlock;

	}



	if (wait_cmd(cmd)) {

		dev_dbg(psp->dev, "doorbell command not done processing\n");

		ret = -EBUSY;

		goto unlock;

	}



	iowrite32(FIELD_PREP(PSP_DRBL_MSG, msg), cmd);

	iowrite32(PSP_DRBL_RING, button);



	if (wait_cmd(cmd)) {

		ret = -ETIMEDOUT;

		goto unlock;

	}



	val = FIELD_GET(PSP_CMDRESP_STS, ioread32(cmd));

	if (val) {

		ret = -EIO;

		goto unlock;

	}



	ret = 0;

unlock:

	mutex_unlock(&pa_dev->doorbell_mutex);



	return ret;

}

EXPORT_SYMBOL_GPL(psp_ring_platform_doorbell);



void platform_access_dev_destroy(struct psp_device *psp)

{

	struct psp_platform_access_device *pa_dev = psp->platform_access_data;
@@ -140,6 +204,7 @@ void platform_access_dev_destroy(struct psp_device *psp) 
		return;



	mutex_destroy(&pa_dev->mailbox_mutex);

	mutex_destroy(&pa_dev->doorbell_mutex);

	psp->platform_access_data = NULL;

}
@@ -159,6 +224,7 @@ int platform_access_dev_init(struct psp_device *psp) 
	pa_dev->vdata = (struct platform_access_vdata *)psp->vdata->platform_access;



	mutex_init(&pa_dev->mailbox_mutex);

	mutex_init(&pa_dev->doorbell_mutex);



	dev_dbg(dev, "platform access enabled\n");

drivers/crypto/ccp/platform-access.h

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ struct psp_platform_access_device { 
	struct platform_access_vdata *vdata;



	struct mutex mailbox_mutex;

	struct mutex doorbell_mutex;



	void *platform_access_data;

};

drivers/crypto/ccp/sp-dev.h

+3 −0
Original line number Diff line number Diff line
@@ -57,6 +57,9 @@ struct platform_access_vdata { 
	const unsigned int cmdresp_reg;

	const unsigned int cmdbuff_addr_lo_reg;

	const unsigned int cmdbuff_addr_hi_reg;

	const unsigned int doorbell_button_reg;

	const unsigned int doorbell_cmd_reg;



};



struct psp_vdata {

drivers/crypto/ccp/sp-pci.c

+2 −0
Original line number Diff line number Diff line
@@ -365,6 +365,8 @@ static const struct platform_access_vdata pa_v1 = { 
	.cmdresp_reg		= 0x10570,	/* C2PMSG_28 */

	.cmdbuff_addr_lo_reg	= 0x10574,	/* C2PMSG_29 */

	.cmdbuff_addr_hi_reg	= 0x10578,	/* C2PMSG_30 */

	.doorbell_button_reg	= 0x10a24,	/* C2PMSG_73 */

	.doorbell_cmd_reg	= 0x10a40,	/* C2PMSG_80 */

};



static const struct psp_vdata pspv1 = {

include/linux/psp-platform-access.h

+15 −0
Original line number Diff line number Diff line
@@ -34,6 +34,21 @@ struct psp_request { 
 */

int psp_send_platform_access_msg(enum psp_platform_access_msg, struct psp_request *req);



/**

 * psp_ring_platform_doorbell() - Ring platform doorbell

 *

 * This function is intended to be used by drivers outside of ccp to ring the

 * platform doorbell with a message.

 *

 * Returns:

 *  0:           success

 *  -%EBUSY:     mailbox in recovery or in use

 *  -%ENODEV:    driver not bound with PSP device

 *  -%ETIMEDOUT: request timed out

 *  -%EIO:       unknown error (see kernel log)

 */

int psp_ring_platform_doorbell(int msg);



/**

 * psp_check_platform_access_status() - Checks whether platform features is ready

 *