1 files changed, 89 insertions, 2 deletions

diff --git a/drivers/char/tpm/tpm_tis_spi_main.c b/drivers/char/tpm/tpm_tis_spi_main.c
index 9bfaba092a06..a62f5c7f38d3 100644
--- a/drivers/char/tpm/tpm_tis_spi_main.c
+++ b/drivers/char/tpm/tpm_tis_spi_main.c
@@ -71,8 +71,74 @@ static int tpm_tis_spi_flow_control(struct tpm_tis_spi_phy *phy,
 	return 0;
 }
 
-int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
-			 u8 *in, const u8 *out)
+/*
+ * Half duplex controller with support for TPM wait state detection like
+ * Tegra QSPI need CMD, ADDR & DATA sent in single message to manage HW flow
+ * control. Each phase sent in different transfer for controller to idenity
+ * phase.
+ */
+static int tpm_tis_spi_transfer_half(struct tpm_tis_data *data,	u32 addr,
+				     u16 len, u8 *in, const u8 *out)
+{
+	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
+	struct spi_transfer spi_xfer[3];
+	struct spi_message m;
+	u8 transfer_len;
+	int ret;
+
+	while (len) {
+		transfer_len = min_t(u16, len, MAX_SPI_FRAMESIZE);
+
+		spi_message_init(&m);
+		phy->iobuf[0] = (in ? 0x80 : 0) | (transfer_len - 1);
+		phy->iobuf[1] = 0xd4;
+		phy->iobuf[2] = addr >> 8;
+		phy->iobuf[3] = addr;
+
+		memset(&spi_xfer, 0, sizeof(spi_xfer));
+
+		spi_xfer[0].tx_buf = phy->iobuf;
+		spi_xfer[0].len = 1;
+		spi_message_add_tail(&spi_xfer[0], &m);
+
+		spi_xfer[1].tx_buf = phy->iobuf + 1;
+		spi_xfer[1].len = 3;
+		spi_message_add_tail(&spi_xfer[1], &m);
+
+		if (out) {
+			spi_xfer[2].tx_buf = &phy->iobuf[4];
+			spi_xfer[2].rx_buf = NULL;
+			memcpy(&phy->iobuf[4], out, transfer_len);
+			out += transfer_len;
+		}
+
+		if (in) {
+			spi_xfer[2].tx_buf = NULL;
+			spi_xfer[2].rx_buf = &phy->iobuf[4];
+		}
+
+		spi_xfer[2].len = transfer_len;
+		spi_message_add_tail(&spi_xfer[2], &m);
+
+		reinit_completion(&phy->ready);
+
+		ret = spi_sync(phy->spi_device, &m);
+		if (ret < 0)
+			return ret;
+
+		if (in) {
+			memcpy(in, &phy->iobuf[4], transfer_len);
+			in += transfer_len;
+		}
+
+		len -= transfer_len;
+	}
+
+	return ret;
+}
+
+static int tpm_tis_spi_transfer_full(struct tpm_tis_data *data, u32 addr,
+				     u16 len, u8 *in, const u8 *out)
 {
 	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
 	int ret = 0;
@@ -148,6 +214,24 @@ exit:
 	return ret;
 }
 
+int tpm_tis_spi_transfer(struct tpm_tis_data *data, u32 addr, u16 len,
+			 u8 *in, const u8 *out)
+{
+	struct tpm_tis_spi_phy *phy = to_tpm_tis_spi_phy(data);
+	struct spi_controller *ctlr = phy->spi_device->controller;
+
+	/*
+	 * TPM flow control over SPI requires full duplex support.
+	 * Send entire message to a half duplex controller to handle
+	 * wait polling in controller.
+	 * Set TPM HW flow control flag..
+	 */
+	if (ctlr->flags & SPI_CONTROLLER_HALF_DUPLEX)
+		return tpm_tis_spi_transfer_half(data, addr, len, in, out);
+	else
+		return tpm_tis_spi_transfer_full(data, addr, len, in, out);
+}
+
 static int tpm_tis_spi_read_bytes(struct tpm_tis_data *data, u32 addr,
 				  u16 len, u8 *result, enum tpm_tis_io_mode io_mode)
 {
@@ -189,6 +273,9 @@ static int tpm_tis_spi_probe(struct spi_device *dev)
 
 	phy->flow_control = tpm_tis_spi_flow_control;
 
+	if (dev->controller->flags & SPI_CONTROLLER_HALF_DUPLEX)
+		dev->mode |= SPI_TPM_HW_FLOW;
+
 	/* If the SPI device has an IRQ then use that */
 	if (dev->irq > 0)
 		irq = dev->irq;