Merge patch series "spi-nor: Add parallel and stacked memories support"

Venkatesh Yadav Abbarapu <[email protected]> says:

This series adds support for Xilinx qspi parallel and
stacked memeories.

In parallel mode, the current implementation assumes that a maximum
of two flashes are connected. The QSPI controller splits the data
evenly between both the flashes so, both the flashes that are connected
in parallel mode should be identical.
During each operation SPI-NOR sets 0th bit for CS0 & 1st bit for CS1 in
nor->flags.

In stacked mode the current implementation assumes that a maximum of two
flashes are connected and both the flashes are of same make but can differ
in sizes. So, except the sizes all other flash parameters of both the flashes
are identical.

Spi-nor will pass on the appropriate flash select flag to low level driver,
and it will select pass all the data to that particular flash.

Write operation in parallel mode are performed in page size * 2 chunks as
each write operation results in writing both the flashes. For doubling the
address space each operation is performed at addr/2 flash offset, where addr
is the address specified by the user.

Similarly for read and erase operations it will read from both flashes, so
size and offset are divided by 2 and send to flash.

2 files changed, 39 insertions, 1 deletions

diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index d1dbf3eadbf..d5f4faf0a68 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -13,6 +13,9 @@
 #include <linux/mtd/mtd.h>
 #include <spi-mem.h>
 
+/* In parallel configuration enable multiple CS */
+#define SPI_NOR_ENABLE_MULTI_CS	(BIT(0) | BIT(1))
+
 /*
  * Manufacturer IDs
  *
@@ -177,6 +180,12 @@
 /* Status Register 2 bits. */
 #define SR2_QUAD_EN_BIT7	BIT(7)
 
+/*
+ * Maximum number of flashes that can be connected
+ * in stacked/parallel configuration
+ */
+#define SNOR_FLASH_CNT_MAX	2
+
 /* For Cypress flash. */
 #define SPINOR_OP_RD_ANY_REG			0x65	/* Read any register */
 #define SPINOR_OP_WR_ANY_REG			0x71	/* Write any register */
@@ -294,6 +303,13 @@ enum spi_nor_option_flags {
 	SNOR_F_BROKEN_RESET	= BIT(6),
 	SNOR_F_SOFT_RESET	= BIT(7),
 	SNOR_F_IO_MODE_EN_VOLATILE = BIT(8),
+#if defined(CONFIG_SPI_ADVANCE)
+	SNOR_F_HAS_STACKED	= BIT(9),
+	SNOR_F_HAS_PARALLEL	= BIT(10),
+#else
+	SNOR_F_HAS_STACKED	= 0,
+	SNOR_F_HAS_PARALLEL	= 0,
+#endif
 };
 
 struct spi_nor;
@@ -551,6 +567,7 @@ struct spi_nor {
 	u8			bank_read_cmd;
 	u8			bank_write_cmd;
 	u8			bank_curr;
+	u8			upage_prev;
 #endif
 	enum spi_nor_protocol	read_proto;
 	enum spi_nor_protocol	write_proto;
diff --git a/include/spi.h b/include/spi.h
index 9e9851284c8..3a92d02f215 100644
--- a/include/spi.h
+++ b/include/spi.h
@@ -38,6 +38,18 @@
 
 #define SPI_DEFAULT_WORDLEN	8
 
+#define SPI_3BYTE_MODE 0x0
+#define SPI_4BYTE_MODE 0x1
+
+/* SPI transfer flags */
+#define SPI_XFER_STRIPE	(1 << 6)
+#define SPI_XFER_MASK	(3 << 8)
+#define SPI_XFER_LOWER	(1 << 8)
+#define SPI_XFER_UPPER	(2 << 8)
+
+/* Max no. of CS supported per spi device */
+#define SPI_CS_CNT_MAX	2
+
 /**
  * struct dm_spi_bus - SPI bus info
  *
@@ -71,7 +83,7 @@ struct dm_spi_bus {
  * @mode:	SPI mode to use for this device (see SPI mode flags)
  */
 struct dm_spi_slave_plat {
-	unsigned int cs;
+	unsigned int cs[SPI_CS_CNT_MAX];
 	uint max_hz;
 	uint mode;
 };
@@ -155,6 +167,15 @@ struct spi_slave {
 #define SPI_XFER_BEGIN		BIT(0)	/* Assert CS before transfer */
 #define SPI_XFER_END		BIT(1)	/* Deassert CS after transfer */
 #define SPI_XFER_ONCE		(SPI_XFER_BEGIN | SPI_XFER_END)
+#define SPI_XFER_U_PAGE		BIT(4)
+#define SPI_XFER_STACKED	BIT(5)
+	/*
+	 * Flag indicating that the spi-controller has multi chip select
+	 * capability and can assert/de-assert more than one chip select
+	 * at once.
+	 */
+	bool multi_cs_cap;
+	u32 bytemode;
 };
 
 /**