crypto: ccp - Move direct access to some PSP registers out of TEE

With the PSP mailbox registers supporting more than just TEE, access to
them must be maintained and serialized by the PSP device support. Remove
TEE support direct access and create an interface in the PSP support
where the register access can be controlled/serialized.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Reviewed-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Tested-by: Rijo Thomas <Rijo-john.Thomas@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 60 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index d42d7bc62352..3258c4612e14 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -9,6 +9,9 @@
 
 #include <linux/kernel.h>
 #include <linux/irqreturn.h>
+#include <linux/mutex.h>
+#include <linux/bitfield.h>
+#include <linux/delay.h>
 
 #include "sp-dev.h"
 #include "psp-dev.h"
@@ -19,6 +22,62 @@
 
 struct psp_device *psp_master;
 
+#define PSP_C2PMSG_17_CMDRESP_CMD	GENMASK(19, 16)
+
+static int psp_mailbox_poll(const void __iomem *cmdresp_reg, unsigned int *cmdresp,
+			    unsigned int timeout_msecs)
+{
+	while (true) {
+		*cmdresp = ioread32(cmdresp_reg);
+		if (FIELD_GET(PSP_CMDRESP_RESP, *cmdresp))
+			return 0;
+
+		if (!timeout_msecs--)
+			break;
+
+		usleep_range(1000, 1100);
+	}
+
+	return -ETIMEDOUT;
+}
+
+int psp_mailbox_command(struct psp_device *psp, enum psp_cmd cmd, void *cmdbuff,
+			unsigned int timeout_msecs, unsigned int *cmdresp)
+{
+	void __iomem *cmdresp_reg, *cmdbuff_lo_reg, *cmdbuff_hi_reg;
+	int ret;
+
+	if (!psp || !psp->vdata || !psp->vdata->cmdresp_reg ||
+	    !psp->vdata->cmdbuff_addr_lo_reg || !psp->vdata->cmdbuff_addr_hi_reg)
+		return -ENODEV;
+
+	cmdresp_reg    = psp->io_regs + psp->vdata->cmdresp_reg;
+	cmdbuff_lo_reg = psp->io_regs + psp->vdata->cmdbuff_addr_lo_reg;
+	cmdbuff_hi_reg = psp->io_regs + psp->vdata->cmdbuff_addr_hi_reg;
+
+	mutex_lock(&psp->mailbox_mutex);
+
+	/* Ensure mailbox is ready for a command */
+	ret = -EBUSY;
+	if (psp_mailbox_poll(cmdresp_reg, cmdresp, 0))
+		goto unlock;
+
+	if (cmdbuff) {
+		iowrite32(lower_32_bits(__psp_pa(cmdbuff)), cmdbuff_lo_reg);
+		iowrite32(upper_32_bits(__psp_pa(cmdbuff)), cmdbuff_hi_reg);
+	}
+
+	*cmdresp = FIELD_PREP(PSP_C2PMSG_17_CMDRESP_CMD, cmd);
+	iowrite32(*cmdresp, cmdresp_reg);
+
+	ret = psp_mailbox_poll(cmdresp_reg, cmdresp, timeout_msecs);
+
+unlock:
+	mutex_unlock(&psp->mailbox_mutex);
+
+	return ret;
+}
+
 static struct psp_device *psp_alloc_struct(struct sp_device *sp)
 {
 	struct device *dev = sp->dev;
@@ -164,6 +223,7 @@ int psp_dev_init(struct sp_device *sp)
 	}
 
 	psp->io_regs = sp->io_map;
+	mutex_init(&psp->mailbox_mutex);
 
 	ret = psp_get_capability(psp);
 	if (ret)