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i3c: master: Add inline i3c_readl_fifo() and i3c_writel_fifo()

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The I3C abstraction expects u8 buffers, but some controllers operate with
a 32-bit bus width FIFO and cannot flag valid bytes individually. To avoid
reading or writing outside the buffer bounds, use 32-bit accesses where
possible and apply memcpy for any remaining bytes

Signed-off-by: Jorge Marques <jorge.marques@analog.com>
Suggested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20250624-i3c-writesl-readsl-v3-1-63ccf0870f01@analog.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Jorge Marques 2025-06-24 11:06:04 +02:00 committed by Alexandre Belloni
parent 12aa3e0cb0
commit 733b439375
1 changed files with 37 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

37
drivers/i3c/internals.h
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@ -22,4 +22,41 @@ int i3c_dev_enable_ibi_locked(struct i3c_dev_desc *dev);
int i3c_dev_request_ibi_locked(struct i3c_dev_desc *dev,
const struct i3c_ibi_setup *req);
void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev);
/**
* i3c_writel_fifo - Write data buffer to 32bit FIFO
* @addr: FIFO Address to write to
* @buf: Pointer to the data bytes to write
* @nbytes: Number of bytes to write
*/
static inline void i3c_writel_fifo(void __iomem *addr, const void *buf,
int nbytes)
{
writesl(addr, buf, nbytes / 4);
if (nbytes & 3) {
u32 tmp = 0;
memcpy(&tmp, buf + (nbytes & ~3), nbytes & 3);
writel(tmp, addr);
}
}
/**
* i3c_readl_fifo - Read data buffer from 32bit FIFO
* @addr: FIFO Address to read from
* @buf: Pointer to the buffer to store read bytes
* @nbytes: Number of bytes to read
*/
static inline void i3c_readl_fifo(const void __iomem *addr, void *buf,
int nbytes)
{
readsl(addr, buf, nbytes / 4);
if (nbytes & 3) {
u32 tmp;
tmp = readl(addr);
memcpy(buf + (nbytes & ~3), &tmp, nbytes & 3);
}
}
#endif /* I3C_INTERNAL_H */