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Subject[PATCH 2/2] mtd: spi-nor: Rework hwcaps selection for the spi-mem case
Date
From: Boris Brezillon <boris.brezillon@bootlin.com>

The spi-mem layer provides a spi_mem_supports_op() function to check
whether a specific operation is supported by the controller or not.
This is much more accurate than the hwcaps selection logic based on
SPI_{RX,TX}_ flags.

Rework the hwcaps selection logic to use spi_mem_supports_op() when
nor->spimem != NULL.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
---
Chagnes wrt RFC:
Fix checkpatch issues
Rebase onto latest

drivers/mtd/spi-nor/spi-nor.c | 164 ++++++++++++++++++++++++++--------
include/linux/mtd/spi-nor.h | 14 +++
2 files changed, 142 insertions(+), 36 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 03c8c346c9ae..d48ae3c9661d 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -2852,6 +2852,110 @@ static int spi_nor_read_sfdp(struct spi_nor *nor, u32 addr,
return ret;
}

+static int spi_nor_spimem_check_readop(struct spi_nor *nor,
+ const struct spi_nor_read_command *read)
+{
+ struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(read->opcode, 1),
+ SPI_MEM_OP_ADDR(3, 0, 1),
+ SPI_MEM_OP_DUMMY(0, 1),
+ SPI_MEM_OP_DATA_IN(0, NULL, 1));
+
+ op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(read->proto);
+ op.addr.buswidth = spi_nor_get_protocol_addr_nbits(read->proto);
+ op.data.buswidth = spi_nor_get_protocol_data_nbits(read->proto);
+ op.dummy.buswidth = op.addr.buswidth;
+ op.dummy.nbytes = (read->num_mode_clocks + read->num_wait_states) *
+ op.dummy.buswidth / 8;
+
+ /*
+ * First test with 3 address bytes. The opcode itself might already
+ * be a 4B addressing opcode but we don't care, because SPI controller
+ * implementation should not check the opcode, but just the sequence.
+ */
+ if (!spi_mem_supports_op(nor->spimem, &op))
+ return -ENOTSUPP;
+
+ /* Now test with 4 address bytes. */
+ op.addr.nbytes = 4;
+ if (!spi_mem_supports_op(nor->spimem, &op))
+ return -ENOTSUPP;
+
+ return 0;
+}
+
+static int spi_nor_spimem_check_progop(struct spi_nor *nor,
+ const struct spi_nor_pp_command *pp)
+{
+ struct spi_mem_op op = SPI_MEM_OP(SPI_MEM_OP_CMD(pp->opcode, 1),
+ SPI_MEM_OP_ADDR(3, 0, 1),
+ SPI_MEM_OP_NO_DUMMY,
+ SPI_MEM_OP_DATA_OUT(0, NULL, 1));
+
+ op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(pp->proto);
+ op.addr.buswidth = spi_nor_get_protocol_addr_nbits(pp->proto);
+ op.data.buswidth = spi_nor_get_protocol_data_nbits(pp->proto);
+
+ /*
+ * First test with 3 address bytes. The opcode itself might already
+ * be a 4B addressing opcode but we don't care, because SPI controller
+ * implementation should not check the opcode, but just the sequence.
+ */
+ if (!spi_mem_supports_op(nor->spimem, &op))
+ return -ENOTSUPP;
+
+ /* Now test with 4 address bytes. */
+ op.addr.nbytes = 4;
+ if (!spi_mem_supports_op(nor->spimem, &op))
+ return -ENOTSUPP;
+
+ return 0;
+}
+
+static void
+spi_nor_spimem_adjust_hwcaps(struct spi_nor *nor,
+ const struct spi_nor_flash_parameter *params,
+ u32 *hwcaps)
+{
+ unsigned int cap;
+
+ /* DTR modes are not supported yet, mask them all. */
+ *hwcaps &= ~SNOR_HWCAPS_DTR;
+
+ /* X-X-X modes are not supported yet, mask them all. */
+ *hwcaps &= ~SNOR_HWCAPS_X_X_X;
+
+ /* Start with read commands. */
+ for (cap = 0; cap < 32; cap++) {
+ int idx;
+
+ if (!(*hwcaps & BIT(cap)))
+ continue;
+
+ idx = spi_nor_hwcaps_read2cmd(BIT(cap));
+ if (idx < 0)
+ continue;
+
+ if (spi_nor_spimem_check_readop(nor, &params->reads[idx]))
+ *hwcaps &= ~BIT(cap);
+ }
+
+ /* Now check program commands. */
+ for (cap = 0; cap < 32; cap++) {
+ int idx;
+
+ if (!(*hwcaps & BIT(cap)))
+ continue;
+
+ idx = spi_nor_hwcaps_pp2cmd(BIT(cap));
+ if (idx < 0)
+ continue;
+
+ if (spi_nor_spimem_check_progop(nor,
+ &params->page_programs[idx]))
+ *hwcaps &= ~BIT(cap);
+ }
+}
+
/**
* spi_nor_read_sfdp_dma_unsafe() - read Serial Flash Discoverable Parameters.
* @nor: pointer to a 'struct spi_nor'
@@ -4259,16 +4363,25 @@ static int spi_nor_setup(struct spi_nor *nor,
*/
shared_mask = hwcaps->mask & params->hwcaps.mask;

- /* SPI n-n-n protocols are not supported yet. */
- ignored_mask = (SNOR_HWCAPS_READ_2_2_2 |
- SNOR_HWCAPS_READ_4_4_4 |
- SNOR_HWCAPS_READ_8_8_8 |
- SNOR_HWCAPS_PP_4_4_4 |
- SNOR_HWCAPS_PP_8_8_8);
- if (shared_mask & ignored_mask) {
- dev_dbg(nor->dev,
- "SPI n-n-n protocols are not supported yet.\n");
- shared_mask &= ~ignored_mask;
+ if (nor->spimem) {
+ /*
+ * When called from spi_nor_probe(), all caps are set and we
+ * need to discard some of them based on what the SPI
+ * controller actually supports (using spi_mem_supports_op()).
+ */
+ spi_nor_spimem_adjust_hwcaps(nor, params, &shared_mask);
+ } else {
+ /*
+ * SPI n-n-n protocols are not supported when the SPI
+ * controller directly implements the spi_nor interface.
+ * Yet another reason to switch to spi-mem.
+ */
+ ignored_mask = SNOR_HWCAPS_X_X_X;
+ if (shared_mask & ignored_mask) {
+ dev_dbg(nor->dev,
+ "SPI n-n-n protocols are not supported.\n");
+ shared_mask &= ~ignored_mask;
+ }
}

/* Select the (Fast) Read command. */
@@ -4591,11 +4704,11 @@ static int spi_nor_probe(struct spi_mem *spimem)
struct spi_device *spi = spimem->spi;
struct flash_platform_data *data;
struct spi_nor *nor;
- struct spi_nor_hwcaps hwcaps = {
- .mask = SNOR_HWCAPS_READ |
- SNOR_HWCAPS_READ_FAST |
- SNOR_HWCAPS_PP,
- };
+ /*
+ * Enable all caps by default. The core will mask them after
+ * checking what's really supported using spi_mem_supports_op().
+ */
+ struct spi_nor_hwcaps hwcaps = { .mask = SNOR_HWCAPS_ALL };
char *flash_name;
int ret;

@@ -4624,27 +4737,6 @@ static int spi_nor_probe(struct spi_mem *spimem)

spi_mem_set_drvdata(spimem, nor);

- if (spi->mode & SPI_RX_OCTAL) {
- hwcaps.mask |= SNOR_HWCAPS_READ_1_1_8;
-
- if (spi->mode & SPI_TX_OCTAL)
- hwcaps.mask |= (SNOR_HWCAPS_READ_1_8_8 |
- SNOR_HWCAPS_PP_1_1_8 |
- SNOR_HWCAPS_PP_1_8_8);
- } else if (spi->mode & SPI_RX_QUAD) {
- hwcaps.mask |= SNOR_HWCAPS_READ_1_1_4;
-
- if (spi->mode & SPI_TX_QUAD)
- hwcaps.mask |= (SNOR_HWCAPS_READ_1_4_4 |
- SNOR_HWCAPS_PP_1_1_4 |
- SNOR_HWCAPS_PP_1_4_4);
- } else if (spi->mode & SPI_RX_DUAL) {
- hwcaps.mask |= SNOR_HWCAPS_READ_1_1_2;
-
- if (spi->mode & SPI_TX_DUAL)
- hwcaps.mask |= SNOR_HWCAPS_READ_1_2_2;
- }
-
if (data && data->name)
nor->mtd.name = data->name;

diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index ac16745f5ef8..1d56c437f553 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -523,6 +523,20 @@ struct spi_nor_hwcaps {
#define SNOR_HWCAPS_PP_1_8_8 BIT(21)
#define SNOR_HWCAPS_PP_8_8_8 BIT(22)

+#define SNOR_HWCAPS_X_X_X (SNOR_HWCAPS_READ_2_2_2 | \
+ SNOR_HWCAPS_READ_4_4_4 | \
+ SNOR_HWCAPS_READ_8_8_8 | \
+ SNOR_HWCAPS_PP_4_4_4 | \
+ SNOR_HWCAPS_PP_8_8_8)
+
+#define SNOR_HWCAPS_DTR (SNOR_HWCAPS_READ_1_1_1_DTR | \
+ SNOR_HWCAPS_READ_1_2_2_DTR | \
+ SNOR_HWCAPS_READ_1_4_4_DTR | \
+ SNOR_HWCAPS_READ_1_8_8_DTR)
+
+#define SNOR_HWCAPS_ALL (SNOR_HWCAPS_READ_MASK | \
+ SNOR_HWCAPS_PP_MASK)
+
/**
* spi_nor_scan() - scan the SPI NOR
* @nor: the spi_nor structure
--
2.21.0
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