[PATCH V2 6/8] spi: spi_amd: Add support for HID2 SPI controller

[Raju Rangoju <Raju.Rangoju@xxxxxxx>]

AMD SoC has HID2 SPI controller in addition to the existing SPI0
controller(AMDI0062). Add HID2 SPI controller's ACPI ID AMDI0063 with its
version ID to the list of supported devices. Use the version ID to
differentiate the register offsets.

And, the AMD HID2 SPI controller supports DMA read, allowing for up to 4 KB
of data to be read in single transaction. Update the SPI-MEM support
function to reflect this capability.

Co-developed-by: Krishnamoorthi M <krishnamoorthi.m@xxxxxxx>
Signed-off-by: Krishnamoorthi M <krishnamoorthi.m@xxxxxxx>
Co-developed-by: Akshata MukundShetty <akshata.mukundshetty@xxxxxxx>
Signed-off-by: Akshata MukundShetty <akshata.mukundshetty@xxxxxxx>
Signed-off-by: Raju Rangoju <Raju.Rangoju@xxxxxxx>
---
 drivers/spi/spi-amd.c | 42 ++++++++++++++++++++++++++++++++++++++----
 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-amd.c b/drivers/spi/spi-amd.c
index 00fcec903d91..f146366a67e7 100644
--- a/drivers/spi/spi-amd.c
+++ b/drivers/spi/spi-amd.c
@@ -38,6 +38,7 @@
 #define AMD_SPI_FIFO_SIZE	70
 #define AMD_SPI_MEM_SIZE	200
 #define AMD_SPI_MAX_DATA	64
+#define AMD_SPI_HID2_DMA_SIZE   4096
 
 #define AMD_SPI_ENA_REG		0x20
 #define AMD_SPI_ALT_SPD_SHIFT	20
@@ -70,10 +71,12 @@
  * enum amd_spi_versions - SPI controller versions
  * @AMD_SPI_V1:		AMDI0061 hardware version
  * @AMD_SPI_V2:		AMDI0062 hardware version
+ * @AMD_HID2_SPI:	AMDI0063 hardware version
  */
 enum amd_spi_versions {
 	AMD_SPI_V1 = 1,
 	AMD_SPI_V2,
+	AMD_HID2_SPI,
 };
 
 enum amd_spi_speed {
@@ -182,6 +185,7 @@ static int amd_spi_set_opcode(struct amd_spi *amd_spi, u8 cmd_opcode)
 				       AMD_SPI_OPCODE_MASK);
 		return 0;
 	case AMD_SPI_V2:
+	case AMD_HID2_SPI:
 		amd_spi_writereg8(amd_spi, AMD_SPI_OPCODE_REG, cmd_opcode);
 		return 0;
 	default:
@@ -209,6 +213,7 @@ static int amd_spi_busy_wait(struct amd_spi *amd_spi)
 		reg = AMD_SPI_CTRL0_REG;
 		break;
 	case AMD_SPI_V2:
+	case AMD_HID2_SPI:
 		reg = AMD_SPI_STATUS_REG;
 		break;
 	default:
@@ -234,6 +239,7 @@ static int amd_spi_execute_opcode(struct amd_spi *amd_spi)
 				       AMD_SPI_EXEC_CMD);
 		return 0;
 	case AMD_SPI_V2:
+	case AMD_HID2_SPI:
 		/* Trigger the command execution */
 		amd_spi_setclear_reg8(amd_spi, AMD_SPI_CMD_TRIGGER_REG,
 				      AMD_SPI_TRIGGER_CMD, AMD_SPI_TRIGGER_CMD);
@@ -375,6 +381,7 @@ static inline int amd_spi_fifo_xfer(struct amd_spi *amd_spi,
 	case AMD_SPI_V1:
 		break;
 	case AMD_SPI_V2:
+	case AMD_HID2_SPI:
 		amd_spi_clear_chip(amd_spi, spi_get_chipselect(message->spi, 0));
 		break;
 	default:
@@ -418,15 +425,29 @@ static inline bool amd_is_spi_read_cmd(const u16 op)
 static bool amd_spi_supports_op(struct spi_mem *mem,
 				const struct spi_mem_op *op)
 {
+	struct amd_spi *amd_spi = spi_controller_get_devdata(mem->spi->controller);
+
 	/* bus width is number of IO lines used to transmit */
-	if (op->cmd.buswidth > 1 || op->addr.buswidth > 4 || op->data.nbytes > AMD_SPI_MAX_DATA)
+	if (op->cmd.buswidth > 1 || op->addr.buswidth > 4)
 		return false;
 
 	/* AMD SPI controllers support quad mode only for read operations */
 	if (amd_is_spi_read_cmd(op->cmd.opcode)) {
 		if (op->data.buswidth > 4)
 			return false;
-	} else if (op->data.buswidth > 1) {
+
+		/*
+		 * HID2 SPI controller supports DMA read up to 4K bytes and
+		 * doesn't support 4-byte address commands.
+		 */
+		if (amd_spi->version == AMD_HID2_SPI) {
+			if (amd_is_spi_read_cmd_4b(op->cmd.opcode) ||
+			    op->data.nbytes > AMD_SPI_HID2_DMA_SIZE)
+				return false;
+		} else if (op->data.nbytes > AMD_SPI_MAX_DATA) {
+			return false;
+		}
+	} else if (op->data.buswidth > 1 || op->data.nbytes > AMD_SPI_MAX_DATA) {
 		return false;
 	}
 
@@ -435,7 +456,19 @@ static bool amd_spi_supports_op(struct spi_mem *mem,
 
 static int amd_spi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 {
-	op->data.nbytes = clamp_val(op->data.nbytes, 0, AMD_SPI_MAX_DATA);
+	struct amd_spi *amd_spi = spi_controller_get_devdata(mem->spi->controller);
+
+	/*
+	 * HID2 SPI controller DMA read mode supports reading up to 4k
+	 * bytes in single transaction, where as SPI0 and HID2 SPI
+	 * controller index mode supports maximum of 64 bytes in a single
+	 * transaction.
+	 */
+	if (amd_spi->version == AMD_HID2_SPI && amd_is_spi_read_cmd(op->cmd.opcode))
+		op->data.nbytes = clamp_val(op->data.nbytes, 0, AMD_SPI_HID2_DMA_SIZE);
+	else
+		op->data.nbytes = clamp_val(op->data.nbytes, 0, AMD_SPI_MAX_DATA);
+
 	return 0;
 }
 
@@ -592,7 +625,7 @@ static int amd_spi_probe(struct platform_device *pdev)
 	amd_spi->version = (uintptr_t) device_get_match_data(dev);
 
 	/* Initialize the spi_controller fields */
-	host->bus_num = 0;
+	host->bus_num = (amd_spi->version == AMD_HID2_SPI) ? 2 : 0;
 	host->num_chipselect = 4;
 	host->mode_bits = SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD;
 	host->flags = SPI_CONTROLLER_HALF_DUPLEX;
@@ -616,6 +649,7 @@ static int amd_spi_probe(struct platform_device *pdev)
 static const struct acpi_device_id spi_acpi_match[] = {
 	{ "AMDI0061", AMD_SPI_V1 },
 	{ "AMDI0062", AMD_SPI_V2 },
+	{ "AMDI0063", AMD_HID2_SPI },
 	{},
 };
 MODULE_DEVICE_TABLE(acpi, spi_acpi_match);
-- 
2.34.1