Merge series "spi: spi-mtk-nor: make use of full capability of program mode"...

Merge series "spi: spi-mtk-nor: make use of full capability of program mode" from Chuanhong Guo <gch981213@gmail.com>:

"program" mode on this controller can trigger up to 56 bits of data
shifting. During the operation, data in PRGDATA[0-5] will be
shifted out from MOSI, and data from MISO will be continuously filling
SHREG[0-9].
Currently this mode is used to implement transfer_one_message for 6-byte
full-duplex transfer, but it can execute a transfer for up-to 7 bytes
as long as the last byte is read only.
transfer_one_message is expected to perform full-duplex transfer,
instead of transfer with specific format. mtk_nor_spi_mem_prg is
added here to use this extra byte.

Newer version of this controller can trigger longer data shifting with
shift bytes more than PRGDATA_MAX + SHREG_MAX. This patch is implemented
with that in mind and it checks against both SHREG_MAX and PRG_CNT_MAX
for future support of new controllers.

Patch 3/3 is a fix for:
commit a59b2c7c ("spi: spi-mtk-nor: support standard spi properties")
which breaks supports_op logic. But it can't be separated as it depends
on patch 2/3. Fortuantely the broken commit isn't in stable yet.

Chuanhong Guo (3):
  spi: spi-mtk-nor: make use of full capability of prg mode
  spi: spi-mtk-nor: add helper for checking prg mode ops
  spi: spi-mtk-nor: fix op checks in supports_op

 drivers/spi/spi-mtk-nor.c | 179 +++++++++++++++++++++++++++++++++-----
 1 file changed, 158 insertions(+), 21 deletions(-)

--
2.26.2

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drivers/spi/spi-mtk-nor.c

@@ -27,6 +27,7 @@
 #define MTK_NOR_CMD_MASK		GENMASK(5, 0)
 
 #define MTK_NOR_REG_PRG_CNT		0x04
+#define MTK_NOR_PRG_CNT_MAX		56
 #define MTK_NOR_REG_RDATA		0x0c
 
 #define MTK_NOR_REG_RADR0		0x10
@@ -167,10 +168,76 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
 	return false;
 }
 
-static int mtk_nor_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+static bool mtk_nor_match_prg(const struct spi_mem_op *op)
+{
+	int tx_len, rx_len, prg_len, prg_left;
+
+	// prg mode is spi-only.
+	if ((op->cmd.buswidth > 1) || (op->addr.buswidth > 1) ||
+	    (op->dummy.buswidth > 1) || (op->data.buswidth > 1))
+		return false;
+
+	tx_len = op->cmd.nbytes + op->addr.nbytes;
+
+	if (op->data.dir == SPI_MEM_DATA_OUT) {
+		// count dummy bytes only if we need to write data after it
+		tx_len += op->dummy.nbytes;
+
+		// leave at least one byte for data
+		if (tx_len > MTK_NOR_REG_PRGDATA_MAX)
+			return false;
+
+		// if there's no addr, meaning adjust_op_size is impossible,
+		// check data length as well.
+		if ((!op->addr.nbytes) &&
+		    (tx_len + op->data.nbytes > MTK_NOR_REG_PRGDATA_MAX + 1))
+			return false;
+	} else if (op->data.dir == SPI_MEM_DATA_IN) {
+		if (tx_len > MTK_NOR_REG_PRGDATA_MAX + 1)
+			return false;
+
+		rx_len = op->data.nbytes;
+		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
+		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
+			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
+		if (rx_len > prg_left) {
+			if (!op->addr.nbytes)
+				return false;
+			rx_len = prg_left;
+		}
+
+		prg_len = tx_len + op->dummy.nbytes + rx_len;
+		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
+			return false;
+	} else {
+		prg_len = tx_len + op->dummy.nbytes;
+		if (prg_len > MTK_NOR_PRG_CNT_MAX / 8)
+			return false;
+	}
+	return true;
+}
+
+static void mtk_nor_adj_prg_size(struct spi_mem_op *op)
 {
-	size_t len;
+	int tx_len, tx_left, prg_left;
 
+	tx_len = op->cmd.nbytes + op->addr.nbytes;
+	if (op->data.dir == SPI_MEM_DATA_OUT) {
+		tx_len += op->dummy.nbytes;
+		tx_left = MTK_NOR_REG_PRGDATA_MAX + 1 - tx_len;
+		if (op->data.nbytes > tx_left)
+			op->data.nbytes = tx_left;
+	} else if (op->data.dir == SPI_MEM_DATA_IN) {
+		prg_left = MTK_NOR_PRG_CNT_MAX / 8 - tx_len - op->dummy.nbytes;
+		if (prg_left > MTK_NOR_REG_SHIFT_MAX + 1)
+			prg_left = MTK_NOR_REG_SHIFT_MAX + 1;
+		if (op->data.nbytes > prg_left)
+			op->data.nbytes = prg_left;
+	}
+}
+
+static int mtk_nor_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
+{
 	if (!op->data.nbytes)
 		return 0;
 
@@ -199,18 +266,15 @@ static int mtk_nor_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 		}
 	}
 
-	len = MTK_NOR_PRG_MAX_SIZE - op->cmd.nbytes - op->addr.nbytes -
-	      op->dummy.nbytes;
-	if (op->data.nbytes > len)
-		op->data.nbytes = len;
-
+	mtk_nor_adj_prg_size(op);
 	return 0;
 }
 
 static bool mtk_nor_supports_op(struct spi_mem *mem,
 				const struct spi_mem_op *op)
 {
-	size_t len;
+	if (!spi_mem_default_supports_op(mem, op))
+		return false;
 
 	if (op->cmd.buswidth != 1)
 		return false;
@@ -218,25 +282,21 @@ static bool mtk_nor_supports_op(struct spi_mem *mem,
 	if ((op->addr.nbytes == 3) || (op->addr.nbytes == 4)) {
 		switch(op->data.dir) {
 		case SPI_MEM_DATA_IN:
-			if (!mtk_nor_match_read(op))
-				return false;
+			if (mtk_nor_match_read(op))
+				return true;
 			break;
 		case SPI_MEM_DATA_OUT:
-			if ((op->addr.buswidth != 1) ||
-			    (op->dummy.nbytes != 0) ||
-			    (op->data.buswidth != 1))
-				return false;
+			if ((op->addr.buswidth == 1) &&
+			    (op->dummy.nbytes == 0) &&
+			    (op->data.buswidth == 1))
+				return true;
 			break;
 		default:
 			break;
 		}
 	}
-	len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
-	if ((len > MTK_NOR_PRG_MAX_SIZE) ||
-	    ((op->data.nbytes) && (len == MTK_NOR_PRG_MAX_SIZE)))
-		return false;
 
-	return spi_mem_default_supports_op(mem, op);
+	return mtk_nor_match_prg(op);
 }
 
 static void mtk_nor_setup_bus(struct mtk_nor *sp, const struct spi_mem_op *op)
@@ -404,6 +464,83 @@ static int mtk_nor_pp_unbuffered(struct mtk_nor *sp,
 	return mtk_nor_cmd_exec(sp, MTK_NOR_CMD_WRITE, 6 * BITS_PER_BYTE);
 }
 
+static int mtk_nor_spi_mem_prg(struct mtk_nor *sp, const struct spi_mem_op *op)
+{
+	int rx_len = 0;
+	int reg_offset = MTK_NOR_REG_PRGDATA_MAX;
+	int tx_len, prg_len;
+	int i, ret;
+	void __iomem *reg;
+	u8 bufbyte;
+
+	tx_len = op->cmd.nbytes + op->addr.nbytes;
+
+	// count dummy bytes only if we need to write data after it
+	if (op->data.dir == SPI_MEM_DATA_OUT)
+		tx_len += op->dummy.nbytes + op->data.nbytes;
+	else if (op->data.dir == SPI_MEM_DATA_IN)
+		rx_len = op->data.nbytes;
+
+	prg_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes +
+		  op->data.nbytes;
+
+	// an invalid op may reach here if the caller calls exec_op without
+	// adjust_op_size. return -EINVAL instead of -ENOTSUPP so that
+	// spi-mem won't try this op again with generic spi transfers.
+	if ((tx_len > MTK_NOR_REG_PRGDATA_MAX + 1) ||
+	    (rx_len > MTK_NOR_REG_SHIFT_MAX + 1) ||
+	    (prg_len > MTK_NOR_PRG_CNT_MAX / 8))
+		return -EINVAL;
+
+	// fill tx data
+	for (i = op->cmd.nbytes; i > 0; i--, reg_offset--) {
+		reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
+		bufbyte = (op->cmd.opcode >> ((i - 1) * BITS_PER_BYTE)) & 0xff;
+		writeb(bufbyte, reg);
+	}
+
+	for (i = op->addr.nbytes; i > 0; i--, reg_offset--) {
+		reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
+		bufbyte = (op->addr.val >> ((i - 1) * BITS_PER_BYTE)) & 0xff;
+		writeb(bufbyte, reg);
+	}
+
+	if (op->data.dir == SPI_MEM_DATA_OUT) {
+		for (i = 0; i < op->dummy.nbytes; i++, reg_offset--) {
+			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
+			writeb(0, reg);
+		}
+
+		for (i = 0; i < op->data.nbytes; i++, reg_offset--) {
+			reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
+			writeb(((const u8 *)(op->data.buf.out))[i], reg);
+		}
+	}
+
+	for (; reg_offset >= 0; reg_offset--) {
+		reg = sp->base + MTK_NOR_REG_PRGDATA(reg_offset);
+		writeb(0, reg);
+	}
+
+	// trigger op
+	writel(prg_len * BITS_PER_BYTE, sp->base + MTK_NOR_REG_PRG_CNT);
+	ret = mtk_nor_cmd_exec(sp, MTK_NOR_CMD_PROGRAM,
+			       prg_len * BITS_PER_BYTE);
+	if (ret)
+		return ret;
+
+	// fetch read data
+	reg_offset = 0;
+	if (op->data.dir == SPI_MEM_DATA_IN) {
+		for (i = op->data.nbytes - 1; i >= 0; i--, reg_offset++) {
+			reg = sp->base + MTK_NOR_REG_SHIFT(reg_offset);
+			((u8 *)(op->data.buf.in))[i] = readb(reg);
+		}
+	}
+
+	return 0;
+}
+
 static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 {
 	struct mtk_nor *sp = spi_controller_get_devdata(mem->spi->master);
@@ -411,7 +548,7 @@ static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 
 	if ((op->data.nbytes == 0) ||
 	    ((op->addr.nbytes != 3) && (op->addr.nbytes != 4)))
-		return -ENOTSUPP;
+		return mtk_nor_spi_mem_prg(sp, op);
 
 	if (op->data.dir == SPI_MEM_DATA_OUT) {
 		mtk_nor_set_addr(sp, op);
@@ -441,7 +578,7 @@ static int mtk_nor_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
 		}
 	}
 
-	return -ENOTSUPP;
+	return mtk_nor_spi_mem_prg(sp, op);
 }
 
 static int mtk_nor_setup(struct spi_device *spi)