On 3/2/23 13:42, Mario Limonciello wrote:
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;
Lets spell out doorbell for these two variable names.
+ 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;
This will be non-zero because psp->io_regs will always be non-zero. Maybe
you meant to check the actual pa_dev->vdata->doorbell_reg value?
I think you should squash this and patch #9 together so that patch #8 just
works right away.
+
+ mutex_lock(&pa_dev->mutex);
Does the doorbell register operate independently from the other registers
(C2PMSG_28 - C2PMSG_30)? If it does, you could probably just introduce a
doorbell mutex.
+
+ if (check_recovery(drbl)) {
+ dev_dbg(psp->dev, "in recovery\n");
Maybe a bit more info as to what is "in recovery" (that goes for patch #4,
too) or just prefix it with "doorbell" (and "platform" in #4) since you
now have duplicated messages.
+ ret = -EBUSY;
+ goto unlock;
+ }
+
+ if (wait_cmd(drbl)) {
+ dev_dbg(psp->dev, "not done processing command\n");
Ditto.
Thanks,
Tom
+ 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 */
