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 <[e-mail]>
Signed-off-by: Mario Limonciello <[e-mail]>
Reviewed-by: Rijo Thomas <[e-mail]>
Tested-by: Rijo Thomas <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

drivers/crypto/ccp/psp-dev.c

···
 
 #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"
···
 #include "dbc.h"
 
 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)
 {
···
 	}
 
 	psp->io_regs = sp->io_map;
+	mutex_init(&psp->mailbox_mutex);
 
 	ret = psp_get_capability(psp);
 	if (ret)

drivers/crypto/ccp/psp-dev.h

···
 #include <linux/list.h>
 #include <linux/bits.h>
 #include <linux/interrupt.h>
+#include <linux/mutex.h>
+#include <linux/psp.h>
 
 #include "sp-dev.h"
 
···
 	struct sp_device *sp;
 
 	void __iomem *io_regs;
+	struct mutex mailbox_mutex;
 
 	psp_irq_handler_t sev_irq_handler;
 	void *sev_irq_data;
···
 #define PSP_SECURITY_RPMC_SPIROM_AVAILABLE	BIT(9)
 #define PSP_SECURITY_HSP_TPM_AVAILABLE		BIT(10)
 #define PSP_SECURITY_ROM_ARMOR_ENFORCED		BIT(11)
+
+/**
+ * enum psp_cmd - PSP mailbox commands
+ * @PSP_CMD_TEE_RING_INIT:	Initialize TEE ring buffer
+ * @PSP_CMD_TEE_RING_DESTROY:	Destroy TEE ring buffer
+ * @PSP_CMD_MAX:		Maximum command id
+ */
+enum psp_cmd {
+	PSP_CMD_TEE_RING_INIT		= 1,
+	PSP_CMD_TEE_RING_DESTROY	= 2,
+	PSP_CMD_MAX			= 15,
+};
+
+int psp_mailbox_command(struct psp_device *psp, enum psp_cmd cmd, void *cmdbuff,
+			unsigned int timeout_msecs, unsigned int *cmdresp);
 
 #endif /* __PSP_DEV_H */

drivers/crypto/ccp/sp-dev.h

···
 	const struct sev_vdata *sev;
 	const struct tee_vdata *tee;
 	const struct platform_access_vdata *platform_access;
+	const unsigned int cmdresp_reg;
+	const unsigned int cmdbuff_addr_lo_reg;
+	const unsigned int cmdbuff_addr_hi_reg;
 	const unsigned int feature_reg;
 	const unsigned int inten_reg;
 	const unsigned int intsts_reg;

drivers/crypto/ccp/sp-pci.c

···
 };
 
 static const struct tee_vdata teev1 = {
-	.cmdresp_reg		= 0x10544,	/* C2PMSG_17 */
-	.cmdbuff_addr_lo_reg	= 0x10548,	/* C2PMSG_18 */
-	.cmdbuff_addr_hi_reg	= 0x1054c,	/* C2PMSG_19 */
 	.ring_wptr_reg          = 0x10550,	/* C2PMSG_20 */
 	.ring_rptr_reg          = 0x10554,	/* C2PMSG_21 */
 	.info_reg		= 0x109e8,	/* C2PMSG_58 */
 };
 
 static const struct tee_vdata teev2 = {
-	.cmdresp_reg		= 0x10944,	/* C2PMSG_17 */
-	.cmdbuff_addr_lo_reg	= 0x10948,	/* C2PMSG_18 */
-	.cmdbuff_addr_hi_reg	= 0x1094c,	/* C2PMSG_19 */
 	.ring_wptr_reg		= 0x10950,	/* C2PMSG_20 */
 	.ring_rptr_reg		= 0x10954,	/* C2PMSG_21 */
 };
···
 static const struct psp_vdata pspv3 = {
 	.tee			= &teev1,
 	.platform_access	= &pa_v1,
+	.cmdresp_reg		= 0x10544,	/* C2PMSG_17 */
+	.cmdbuff_addr_lo_reg	= 0x10548,	/* C2PMSG_18 */
+	.cmdbuff_addr_hi_reg	= 0x1054c,	/* C2PMSG_19 */
 	.bootloader_info_reg	= 0x109ec,	/* C2PMSG_59 */
 	.feature_reg		= 0x109fc,	/* C2PMSG_63 */
 	.inten_reg		= 0x10690,	/* P2CMSG_INTEN */
···
 static const struct psp_vdata pspv4 = {
 	.sev			= &sevv2,
 	.tee			= &teev1,
+	.cmdresp_reg		= 0x10544,	/* C2PMSG_17 */
+	.cmdbuff_addr_lo_reg	= 0x10548,	/* C2PMSG_18 */
+	.cmdbuff_addr_hi_reg	= 0x1054c,	/* C2PMSG_19 */
 	.bootloader_info_reg	= 0x109ec,	/* C2PMSG_59 */
 	.feature_reg		= 0x109fc,	/* C2PMSG_63 */
 	.inten_reg		= 0x10690,	/* P2CMSG_INTEN */
···
 static const struct psp_vdata pspv5 = {
 	.tee			= &teev2,
 	.platform_access	= &pa_v2,
+	.cmdresp_reg		= 0x10944,	/* C2PMSG_17 */
+	.cmdbuff_addr_lo_reg	= 0x10948,	/* C2PMSG_18 */
+	.cmdbuff_addr_hi_reg	= 0x1094c,	/* C2PMSG_19 */
 	.feature_reg		= 0x109fc,	/* C2PMSG_63 */
 	.inten_reg		= 0x10510,	/* P2CMSG_INTEN */
 	.intsts_reg		= 0x10514,	/* P2CMSG_INTSTS */
···
 static const struct psp_vdata pspv6 = {
 	.sev                    = &sevv2,
 	.tee                    = &teev2,
+	.cmdresp_reg		= 0x10944,	/* C2PMSG_17 */
+	.cmdbuff_addr_lo_reg	= 0x10948,	/* C2PMSG_18 */
+	.cmdbuff_addr_hi_reg	= 0x1094c,	/* C2PMSG_19 */
 	.feature_reg            = 0x109fc,	/* C2PMSG_63 */
 	.inten_reg              = 0x10510,	/* P2CMSG_INTEN */
 	.intsts_reg             = 0x10514,	/* P2CMSG_INTSTS */

drivers/crypto/ccp/tee-dev.c

···
 	mutex_destroy(&rb_mgr->mutex);
 }
 
-static int tee_wait_cmd_poll(struct psp_tee_device *tee, unsigned int timeout,
-			     unsigned int *reg)
-{
-	/* ~10ms sleep per loop => nloop = timeout * 100 */
-	int nloop = timeout * 100;
-
-	while (--nloop) {
-		*reg = ioread32(tee->io_regs + tee->vdata->cmdresp_reg);
-		if (FIELD_GET(PSP_CMDRESP_RESP, *reg))
-			return 0;
-
-		usleep_range(10000, 10100);
-	}
-
-	dev_err(tee->dev, "tee: command timed out, disabling PSP\n");
-	psp_dead = true;
-
-	return -ETIMEDOUT;
-}
-
 static
 struct tee_init_ring_cmd *tee_alloc_cmd_buffer(struct psp_tee_device *tee)
 {
···
 {
 	int ring_size = MAX_RING_BUFFER_ENTRIES * sizeof(struct tee_ring_cmd);
 	struct tee_init_ring_cmd *cmd;
-	phys_addr_t cmd_buffer;
 	unsigned int reg;
 	int ret;
 
···
 		return -ENOMEM;
 	}
 
-	cmd_buffer = __psp_pa((void *)cmd);
-
 	/* Send command buffer details to Trusted OS by writing to
 	 * CPU-PSP message registers
 	 */
-
-	iowrite32(lower_32_bits(cmd_buffer),
-		  tee->io_regs + tee->vdata->cmdbuff_addr_lo_reg);
-	iowrite32(upper_32_bits(cmd_buffer),
-		  tee->io_regs + tee->vdata->cmdbuff_addr_hi_reg);
-	iowrite32(TEE_RING_INIT_CMD,
-		  tee->io_regs + tee->vdata->cmdresp_reg);
-
-	ret = tee_wait_cmd_poll(tee, TEE_DEFAULT_TIMEOUT, &reg);
+	ret = psp_mailbox_command(tee->psp, PSP_CMD_TEE_RING_INIT, cmd,
+				  TEE_DEFAULT_CMD_TIMEOUT, &reg);
 	if (ret) {
-		dev_err(tee->dev, "tee: ring init command timed out\n");
+		dev_err(tee->dev, "tee: ring init command timed out, disabling TEE support\n");
 		tee_free_ring(tee);
+		psp_dead = true;
 		goto free_buf;
 	}
 
···
 	if (psp_dead)
 		goto free_ring;
 
-	iowrite32(TEE_RING_DESTROY_CMD,
-		  tee->io_regs + tee->vdata->cmdresp_reg);
-
-	ret = tee_wait_cmd_poll(tee, TEE_DEFAULT_TIMEOUT, &reg);
+	ret = psp_mailbox_command(tee->psp, PSP_CMD_TEE_RING_DESTROY, NULL,
+				  TEE_DEFAULT_CMD_TIMEOUT, &reg);
 	if (ret) {
-		dev_err(tee->dev, "tee: ring destroy command timed out\n");
+		dev_err(tee->dev, "tee: ring destroy command timed out, disabling TEE support\n");
+		psp_dead = true;
 	} else if (FIELD_GET(PSP_CMDRESP_STS, reg)) {
 		dev_err(tee->dev, "tee: ring destroy command failed (%#010lx)\n",
 			FIELD_GET(PSP_CMDRESP_STS, reg));
···
 	if (ret)
 		return ret;
 
-	ret = tee_wait_cmd_completion(tee, resp, TEE_DEFAULT_TIMEOUT);
+	ret = tee_wait_cmd_completion(tee, resp, TEE_DEFAULT_RING_TIMEOUT);
 	if (ret) {
 		resp->flag = CMD_RESPONSE_TIMEDOUT;
 		return ret;

drivers/crypto/ccp/tee-dev.h

···
 #include <linux/device.h>
 #include <linux/mutex.h>
 
-#define TEE_DEFAULT_TIMEOUT		10
+#define TEE_DEFAULT_CMD_TIMEOUT		(10 * MSEC_PER_SEC)
+#define TEE_DEFAULT_RING_TIMEOUT	10
 #define MAX_BUFFER_SIZE			988
-
-/**
- * enum tee_ring_cmd_id - TEE interface commands for ring buffer configuration
- * @TEE_RING_INIT_CMD:		Initialize ring buffer
- * @TEE_RING_DESTROY_CMD:	Destroy ring buffer
- * @TEE_RING_MAX_CMD:		Maximum command id
- */
-enum tee_ring_cmd_id {
-	TEE_RING_INIT_CMD		= 0x00010000,
-	TEE_RING_DESTROY_CMD		= 0x00020000,
-	TEE_RING_MAX_CMD		= 0x000F0000,
-};
 
 /**
  * struct tee_init_ring_cmd - Command to init TEE ring buffer