Tegra TPM driver with HW flow control
Merge series from Krishna Yarlagadda <kyarlagadda@nvidia.com>:
TPM devices may insert wait state on last clock cycle of ADDR phase.
For SPI controllers that support full-duplex transfers, this can be
detected using software by reading the MISO line. For SPI controllers
that only support half-duplex transfers, such as the Tegra QSPI, it is
not possible to detect the wait signal from software. The QSPI
controller in Tegra234 and Tegra241 implement hardware detection of the
wait signal which can be enabled in the controller for TPM devices.
Add a flag for this in the SPI core and implement support in the Tegra
QuadSPI driver.
diff --git a/drivers/spi/spi-tegra210-quad.c b/drivers/spi/spi-tegra210-quad.c
index bea376a..fbd14dd 100644
--- a/drivers/spi/spi-tegra210-quad.c
+++ b/drivers/spi/spi-tegra210-quad.c
@@ -142,6 +142,7 @@
#define QSPI_GLOBAL_CONFIG 0X1a4
#define QSPI_CMB_SEQ_EN BIT(0)
+#define QSPI_TPM_WAIT_POLL_EN BIT(1)
#define QSPI_CMB_SEQ_ADDR 0x1a8
#define QSPI_ADDRESS_VALUE_SET(X) (((x) & 0xFFFF) << 0)
@@ -164,6 +165,7 @@
struct tegra_qspi_soc_data {
bool has_dma;
bool cmb_xfer_capable;
+ bool supports_tpm;
unsigned int cs_count;
};
@@ -1065,6 +1067,12 @@ static int tegra_qspi_combined_seq_xfer(struct tegra_qspi *tqspi,
/* Enable Combined sequence mode */
val = tegra_qspi_readl(tqspi, QSPI_GLOBAL_CONFIG);
+ if (spi->mode & SPI_TPM_HW_FLOW) {
+ if (tqspi->soc_data->supports_tpm)
+ val |= QSPI_TPM_WAIT_POLL_EN;
+ else
+ return -EIO;
+ }
val |= QSPI_CMB_SEQ_EN;
tegra_qspi_writel(tqspi, val, QSPI_GLOBAL_CONFIG);
/* Process individual transfer list */
@@ -1196,6 +1204,8 @@ static int tegra_qspi_non_combined_seq_xfer(struct tegra_qspi *tqspi,
/* Disable Combined sequence mode */
val = tegra_qspi_readl(tqspi, QSPI_GLOBAL_CONFIG);
val &= ~QSPI_CMB_SEQ_EN;
+ if (tqspi->soc_data->supports_tpm)
+ val &= ~QSPI_TPM_WAIT_POLL_EN;
tegra_qspi_writel(tqspi, val, QSPI_GLOBAL_CONFIG);
list_for_each_entry(transfer, &msg->transfers, transfer_list) {
struct spi_transfer *xfer = transfer;
@@ -1454,24 +1464,28 @@ static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data)
static struct tegra_qspi_soc_data tegra210_qspi_soc_data = {
.has_dma = true,
.cmb_xfer_capable = false,
+ .supports_tpm = false,
.cs_count = 1,
};
static struct tegra_qspi_soc_data tegra186_qspi_soc_data = {
.has_dma = true,
.cmb_xfer_capable = true,
+ .supports_tpm = false,
.cs_count = 1,
};
static struct tegra_qspi_soc_data tegra234_qspi_soc_data = {
.has_dma = false,
.cmb_xfer_capable = true,
+ .supports_tpm = true,
.cs_count = 1,
};
static struct tegra_qspi_soc_data tegra241_qspi_soc_data = {
.has_dma = false,
.cmb_xfer_capable = true,
+ .supports_tpm = true,
.cs_count = 4,
};
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 873ced6..cfe42f8 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -184,8 +184,18 @@ struct spi_device {
u8 chip_select;
u8 bits_per_word;
bool rt;
-#define SPI_NO_TX BIT(31) /* No transmit wire */
-#define SPI_NO_RX BIT(30) /* No receive wire */
+#define SPI_NO_TX BIT(31) /* No transmit wire */
+#define SPI_NO_RX BIT(30) /* No receive wire */
+ /*
+ * TPM specification defines flow control over SPI. Client device
+ * can insert a wait state on MISO when address is transmitted by
+ * controller on MOSI. Detecting the wait state in software is only
+ * possible for full duplex controllers. For controllers that support
+ * only half-duplex, the wait state detection needs to be implemented
+ * in hardware. TPM devices would set this flag when hardware flow
+ * control is expected from SPI controller.
+ */
+#define SPI_TPM_HW_FLOW BIT(29) /* TPM HW flow control */
/*
* All bits defined above should be covered by SPI_MODE_KERNEL_MASK.
* The SPI_MODE_KERNEL_MASK has the SPI_MODE_USER_MASK counterpart,
@@ -195,7 +205,7 @@ struct spi_device {
* These bits must not overlap. A static assert check should make sure of that.
* If adding extra bits, make sure to decrease the bit index below as well.
*/
-#define SPI_MODE_KERNEL_MASK (~(BIT(30) - 1))
+#define SPI_MODE_KERNEL_MASK (~(BIT(29) - 1))
u32 mode;
int irq;
void *controller_state;
