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spi: spi-mtk-nor: make use of full capability of prg mode 

"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.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Link: https://lore.kernel.org/r/20200924152730.733243-2-gch981213@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Chuanhong Guo 2020-09-24 23:27:28 +08:00 committed by Mark Brown
parent 9d36215250
commit e7edd2cf4c
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
1 changed files with 80 additions and 2 deletions
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82
drivers/spi/spi-mtk-nor.c
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@ -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
@ -404,6 +405,83 @@ 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 +489,7 @@ 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 +519,7 @@ 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)