crypto: ccp - Add support for ringing a platform doorbell

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@semihalf.com/
Suggested-by: Jan Dabros <jsd@semihalf.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/ccp/platform-access.c b/drivers/crypto/ccp/platform-access.c
index 9cc0c60..b51fb11 100644 (file)
--- 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 @@ unlock:
 }
 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 c3a9789..a83f03b 100644 (file)
--- 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 5ec6c21..1253a02 100644 (file)
--- 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 18aa902..b5896f7 100644 (file)
--- 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 977df5c..89df454 100644 (file)
--- 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
  *
  * This function is intended to be used by drivers outside of ccp to determine

diff --git a/include/linux/psp.h b/include/linux/psp.h
index d342479..92e60ae 100644 (file)
--- 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 */