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Subject[Patch v2 1/4] spi: spi-nxp-fspi: Add support for IP read only
Date
Add support for disabling AHB bus and read entire flash contents via IP
bus only. Please note, this enables IP bus read using a quirk which can
be enabled directly in device-type data or in existence of an errata
where AHB bus may need to be disabled.

Signed-off-by: Kuldeep Singh <kuldeep.singh@nxp.com>
---
v2: No update

drivers/spi/spi-nxp-fspi.c | 28 ++++++++++++++++++++++------
1 file changed, 22 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-nxp-fspi.c b/drivers/spi/spi-nxp-fspi.c
index ab9035662717..829391e20e92 100644
--- a/drivers/spi/spi-nxp-fspi.c
+++ b/drivers/spi/spi-nxp-fspi.c
@@ -311,6 +311,9 @@
#define NXP_FSPI_MAX_CHIPSELECT 4
#define NXP_FSPI_MIN_IOMAP SZ_4M

+/* Access flash memory using IP bus only */
+#define FSPI_QUIRK_USE_IP_ONLY BIT(0)
+
struct nxp_fspi_devtype_data {
unsigned int rxfifo;
unsigned int txfifo;
@@ -359,6 +362,11 @@ struct nxp_fspi {
int selected;
};

+static inline int needs_ip_only(struct nxp_fspi *f)
+{
+ return f->devtype_data->quirks & FSPI_QUIRK_USE_IP_ONLY;
+}
+
/*
* R/W functions for big- or little-endian registers:
* The FSPI controller's endianness is independent of
@@ -553,8 +561,8 @@ static void nxp_fspi_prepare_lut(struct nxp_fspi *f,
for (i = 0; i < ARRAY_SIZE(lutval); i++)
fspi_writel(f, lutval[i], base + FSPI_LUT_REG(i));

- dev_dbg(f->dev, "CMD[%x] lutval[0:%x \t 1:%x \t 2:%x \t 3:%x]\n",
- op->cmd.opcode, lutval[0], lutval[1], lutval[2], lutval[3]);
+ dev_dbg(f->dev, "CMD[%x] lutval[0:%x \t 1:%x \t 2:%x \t 3:%x], size: 0x%08x\n",
+ op->cmd.opcode, lutval[0], lutval[1], lutval[2], lutval[3], op->data.nbytes);

/* lock LUT */
fspi_writel(f, FSPI_LUTKEY_VALUE, f->iobase + FSPI_LUTKEY);
@@ -852,12 +860,14 @@ static int nxp_fspi_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)

nxp_fspi_prepare_lut(f, op);
/*
- * If we have large chunks of data, we read them through the AHB bus
- * by accessing the mapped memory. In all other cases we use
- * IP commands to access the flash.
+ * If we have large chunks of data, we read them through the AHB bus by
+ * accessing the mapped memory. In all other cases we use IP commands
+ * to access the flash. Read via AHB bus may be corrupted due to
+ * existence of an errata and therefore discard AHB read in such cases.
*/
if (op->data.nbytes > (f->devtype_data->rxfifo - 4) &&
- op->data.dir == SPI_MEM_DATA_IN) {
+ op->data.dir == SPI_MEM_DATA_IN &&
+ !needs_ip_only(f)) {
err = nxp_fspi_read_ahb(f, op);
} else {
if (op->data.nbytes && op->data.dir == SPI_MEM_DATA_OUT)
@@ -888,6 +898,12 @@ static int nxp_fspi_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
op->data.nbytes = ALIGN_DOWN(op->data.nbytes, 8);
}

+ /* Limit data bytes to RX FIFO in case of IP read only */
+ if (op->data.dir == SPI_MEM_DATA_IN &&
+ needs_ip_only(f) &&
+ op->data.nbytes > f->devtype_data->rxfifo)
+ op->data.nbytes = f->devtype_data->rxfifo;
+
return 0;
}

--
2.25.1
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