[PATCH v4 7/8] crypto: ccp: Add support for ringing a platform doorbell
From: Mario Limonciello
Date: Fri Mar 10 2023 - 16:25:27 EST
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