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@xxxxxxxxxxxx/ Suggested-by: Jan Dabros <jsd@xxxxxxxxxxxx> Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx> --- v1->v2: * New patch --- drivers/crypto/ccp/platform-access.c | 47 ++++++++++++++++++++++++++++ drivers/crypto/ccp/sp-dev.h | 1 + include/linux/psp-platform-access.h | 15 +++++++++ include/linux/psp.h | 3 ++ 4 files changed, 66 insertions(+) diff --git a/drivers/crypto/ccp/platform-access.c b/drivers/crypto/ccp/platform-access.c index af3a1e97abfe..0763389a2814 100644 --- a/drivers/crypto/ccp/platform-access.c +++ b/drivers/crypto/ccp/platform-access.c @@ -135,6 +135,53 @@ 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(enum psp_platform_access_msg msg) +{ + struct psp_device *psp = psp_get_master_device(); + struct psp_platform_access_device *pa_dev; + u32 __iomem *drbl; + u32 drbl_reg; + int ret; + + if (!psp || !psp->platform_access_data) + return -ENODEV; + + pa_dev = psp->platform_access_data; + drbl = psp->io_regs + pa_dev->vdata->doorbell_reg; + + if (!drbl) + return -ENODEV; + + mutex_lock(&pa_dev->mutex); + + if (check_recovery(drbl)) { + dev_dbg(psp->dev, "in recovery\n"); + ret = -EBUSY; + goto unlock; + } + + if (wait_cmd(drbl)) { + dev_dbg(psp->dev, "not done processing command\n"); + ret = -EBUSY; + goto unlock; + } + + drbl_reg = FIELD_PREP(PSP_DRBL_MSG, msg) | PSP_DRBL_RING; + iowrite32(drbl_reg, drbl); + + if (wait_cmd(drbl)) { + ret = -ETIMEDOUT; + goto unlock; + } + + ret = 0; +unlock: + mutex_unlock(&pa_dev->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; diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h index 5ec6c219a731..87c0b9350bc2 100644 --- a/drivers/crypto/ccp/sp-dev.h +++ b/drivers/crypto/ccp/sp-dev.h @@ -54,6 +54,7 @@ struct tee_vdata { }; struct platform_access_vdata { + const unsigned int doorbell_reg; const unsigned int cmdresp_reg; const unsigned int cmdbuff_addr_lo_reg; const unsigned int cmdbuff_addr_hi_reg; diff --git a/include/linux/psp-platform-access.h b/include/linux/psp-platform-access.h index f5a03cd11f10..1e1d0e077cec 100644 --- a/include/linux/psp-platform-access.h +++ b/include/linux/psp-platform-access.h @@ -35,6 +35,21 @@ 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(enum psp_platform_access_msg); + /** * psp_check_platform_access_status() - Checks whether platform features is ready * diff --git a/include/linux/psp.h b/include/linux/psp.h index d3424790a70e..92e60aeef21e 100644 --- a/include/linux/psp.h +++ b/include/linux/psp.h @@ -23,4 +23,7 @@ #define PSP_CMDRESP_RECOVERY BIT(30) #define PSP_CMDRESP_RESP BIT(31) +#define PSP_DRBL_MSG PSP_CMDRESP_CMD +#define PSP_DRBL_RING BIT(0) + #endif /* __PSP_H */ -- 2.34.1
