Commit 482c84e9 authored by Mario Limonciello's avatar Mario Limonciello Committed by Herbert Xu
Browse files

i2c: designware: Add doorbell support for Mendocino 

Mendocino and later platform don't use the platform feature mailbox for
communication for I2C arbitration, they rely upon ringing a doorbell.

Detect the platform by the device ID of the root port and choose the
appropriate method.

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


Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Acked-by: default avatarJarkko Nikula <jarkko.nikula@linux.intel.com>
Reviewed-by: default avatarMark Hasemeyer <markhas@chromium.org>
Tested-by: default avatarMark Hasemeyer <markhas@chromium.org>
Acked-by: default avatarWolfram Sang <wsa@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 440da737

drivers/i2c/busses/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -568,6 +568,7 @@ config I2C_DESIGNWARE_AMDPSP 
	bool "AMD PSP I2C semaphore support"

	depends on ACPI

	depends on CRYPTO_DEV_SP_PSP

	depends on PCI

	depends on I2C_DESIGNWARE_PLATFORM

	depends on (I2C_DESIGNWARE_PLATFORM=y && CRYPTO_DEV_CCP_DD=y) || \

		   (I2C_DESIGNWARE_PLATFORM=m && CRYPTO_DEV_CCP_DD)

drivers/i2c/busses/i2c-designware-amdpsp.c

+25 −1
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0



#include <linux/i2c.h>

#include <linux/pci.h>

#include <linux/psp-platform-access.h>

#include <linux/psp.h>

#include <linux/workqueue.h>
@@ -32,6 +33,8 @@ static u32 psp_i2c_access_count; 
static bool psp_i2c_mbox_fail;

static struct device *psp_i2c_dev;



static int (*_psp_send_i2c_req)(struct psp_i2c_req *req);



/* Helper to verify status returned by PSP */

static int check_i2c_req_sts(struct psp_i2c_req *req)

{
@@ -72,6 +75,17 @@ static int psp_send_i2c_req_cezanne(struct psp_i2c_req *req) 
	return ret;

}



static int psp_send_i2c_req_doorbell(struct psp_i2c_req *req)

{

	int ret;



	ret = psp_ring_platform_doorbell(req->type, &req->hdr.status);

	if (ret == -EIO)

		return check_i2c_req_sts(req);



	return ret;

}



static int psp_send_i2c_req(enum psp_i2c_req_type i2c_req_type)

{

	struct psp_i2c_req *req;
@@ -87,7 +101,7 @@ static int psp_send_i2c_req(enum psp_i2c_req_type i2c_req_type) 
	req->type = i2c_req_type;



	start = jiffies;

	ret = read_poll_timeout(psp_send_i2c_req_cezanne, status,

	ret = read_poll_timeout(_psp_send_i2c_req, status,

				(status != -EBUSY),

				PSP_I2C_REQ_RETRY_DELAY_US,

				PSP_I2C_REQ_RETRY_CNT * PSP_I2C_REQ_RETRY_DELAY_US,
@@ -262,6 +276,8 @@ static const struct i2c_lock_operations i2c_dw_psp_lock_ops = { 


int i2c_dw_amdpsp_probe_lock_support(struct dw_i2c_dev *dev)

{

	struct pci_dev *rdev;



	if (!IS_REACHABLE(CONFIG_CRYPTO_DEV_CCP_DD))

		return -ENODEV;
@@ -275,6 +291,14 @@ int i2c_dw_amdpsp_probe_lock_support(struct dw_i2c_dev *dev) 
	if (psp_i2c_dev)

		return -EEXIST;



	/* Cezanne uses platform mailbox, Mendocino and later use doorbell */

	rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));

	if (rdev->device == 0x1630)

		_psp_send_i2c_req = psp_send_i2c_req_cezanne;

	else

		_psp_send_i2c_req = psp_send_i2c_req_doorbell;

	pci_dev_put(rdev);



	if (psp_check_platform_access_status())

		return -EPROBE_DEFER;