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> --- v3->v4: * Add a missing check for doorbell status at start * Fix spurious __iomem v2->v3: * Squash register values in * Use command and button registers * Correct register values for incorrect ones previously shared * Use a unique mutex v1->v2: * New patch --- drivers/crypto/ccp/platform-access.c | 66 ++++++++++++++++++++++++++++ drivers/crypto/ccp/platform-access.h | 1 + drivers/crypto/ccp/sp-dev.h | 3 ++ drivers/crypto/ccp/sp-pci.c | 2 + include/linux/psp-platform-access.h | 15 +++++++ include/linux/psp.h | 3 ++ 6 files changed, 90 insertions(+) diff --git a/drivers/crypto/ccp/platform-access.c b/drivers/crypto/ccp/platform-access.c index 9cc0c60bbf7b..b51fb1196932 100644 --- a/drivers/crypto/ccp/platform-access.c +++ b/drivers/crypto/ccp/platform-access.c @@ -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"); diff --git a/drivers/crypto/ccp/platform-access.h b/drivers/crypto/ccp/platform-access.h index c3a97893320d..a83f03beb869 100644 --- a/drivers/crypto/ccp/platform-access.h +++ b/drivers/crypto/ccp/platform-access.h @@ -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; }; diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h index 5ec6c219a731..1253a0217985 100644 --- a/drivers/crypto/ccp/sp-dev.h +++ b/drivers/crypto/ccp/sp-dev.h @@ -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 { diff --git a/drivers/crypto/ccp/sp-pci.c b/drivers/crypto/ccp/sp-pci.c index 18aa902eb5ce..b5896f7af7ab 100644 --- a/drivers/crypto/ccp/sp-pci.c +++ b/drivers/crypto/ccp/sp-pci.c @@ -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 = { diff --git a/include/linux/psp-platform-access.h b/include/linux/psp-platform-access.h index f5a03cd11f10..aca3b148af93 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(int 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
