1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/i2c.h>
5 #include <linux/psp-platform-access.h>
9 #include "i2c-designware-core.h"
43 	/* Status field in command-response buffer is updated by PSP */  in check_i2c_req_sts()
44 	status = READ_ONCE(req->hdr.status);  in check_i2c_req_sts()
50 		return -EBUSY;  in check_i2c_req_sts()
53 		return -EIO;  in check_i2c_req_sts()
58  * Errors in x86-PSP i2c-arbitration protocol may occur at two levels:
59  * 1. mailbox communication - PSP is not operational or some IO errors with
61  * 2. i2c-requests - PSP refuses to grant i2c arbitration to x86 for too long.
65  * up and if -EIO is returned the second level will be checked.
72 	if (ret == -EIO)  in psp_send_i2c_req_cezanne()
82 	ret = psp_ring_platform_doorbell(req->type, &req->hdr.status);  in psp_send_i2c_req_doorbell()
83 	if (ret == -EIO)  in psp_send_i2c_req_doorbell()
95 	/* Allocate command-response buffer */  in psp_send_i2c_req()
98 		return -ENOMEM;  in psp_send_i2c_req()
100 	req->hdr.payload_size = sizeof(*req);  in psp_send_i2c_req()
101 	req->type = i2c_req_type;  in psp_send_i2c_req()
105 				(status != -EBUSY),  in psp_send_i2c_req()
110 		dev_err(psp_i2c_dev, "Timed out waiting for PSP to %s I2C bus\n",  in psp_send_i2c_req()
123 		jiffies_to_msecs(jiffies - start));  in psp_send_i2c_req()
127 		dev_err(psp_i2c_dev, "Assume i2c bus is for exclusive host usage\n");  in psp_send_i2c_req()
147 		jiffies_to_msecs(jiffies - psp_i2c_sem_acquired));  in release_bus()
199 	 * In case of errors with PSP arbitrator psp_i2c_mbox_fail variable is  in psp_acquire_i2c_bus()
201 	 * communication with PSP. At any case i2c bus is granted to the caller,  in psp_acquire_i2c_bus()
221 	psp_i2c_access_count--;  in psp_release_i2c_bus()
238  * drivers/i2c/i2c-core-base.c, but with PSP acquire and release operations
239  * added. With this in place we can ensure that i2c clients on the bus shared
241  * operations - that is e.g. write-wait-read.
247 	rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));  in i2c_adapter_dw_psp_lock_bus()
255 	ret = rt_mutex_trylock(&adapter->bus_lock);  in i2c_adapter_dw_psp_trylock_bus()
268 	rt_mutex_unlock(&adapter->bus_lock);  in i2c_adapter_dw_psp_unlock_bus()
282 		return -ENODEV;  in i2c_dw_amdpsp_probe_lock_support()
285 		return -ENODEV;  in i2c_dw_amdpsp_probe_lock_support()
287 	if (!(dev->flags & ARBITRATION_SEMAPHORE))  in i2c_dw_amdpsp_probe_lock_support()
288 		return -ENODEV;  in i2c_dw_amdpsp_probe_lock_support()
292 		return -EEXIST;  in i2c_dw_amdpsp_probe_lock_support()
296 	if (rdev->device == 0x1630)  in i2c_dw_amdpsp_probe_lock_support()
303 		return -EPROBE_DEFER;  in i2c_dw_amdpsp_probe_lock_support()
305 	psp_i2c_dev = dev->dev;  in i2c_dw_amdpsp_probe_lock_support()
307 	dev_info(psp_i2c_dev, "I2C bus managed by AMD PSP\n");  in i2c_dw_amdpsp_probe_lock_support()
310 	 * Install global locking callbacks for adapter as well as internal i2c  in i2c_dw_amdpsp_probe_lock_support()
313 	dev->adapter.lock_ops = &i2c_dw_psp_lock_ops;  in i2c_dw_amdpsp_probe_lock_support()
314 	dev->acquire_lock = psp_acquire_i2c_bus;  in i2c_dw_amdpsp_probe_lock_support()
315 	dev->release_lock = psp_release_i2c_bus;  in i2c_dw_amdpsp_probe_lock_support()