[PATCH] spi: Fix hang on spi_sync() when driver does not support transfer() call

[PATCH] spi: Fix hang on spi_sync() when driver does not support transfer() call

[Alexander Shiyan]

When a driver does not support transfer() call, such as most QSPI drivers,
calling spi_sync() (e.g. with the "spi" command) will cause the system
to hang. Fix this by adding a function check.

barebox@Mega-Milas Informer SAMA5D2:/ spi -b 1 -c 0 0xaa
prefetch abort
pc : [<00000004>]    lr : [<27e266a4>]
sp : 27ff7c78  ip : 27ff7ce8  fp : 27e87410
r10: 27ff7d20  r9 : 00000000  r8 : 23f58128
r7 : 23f33c30  r6 : 27ff7c90  r5 : 27ff7d20  r4 : 27ff7c7c
r3 : 00000000  r2 : 27ff7cc4  r1 : 27ff7c90  r0 : 27ff7d20
Flags: nzCv  IRQs off  FIQs off  Mode SVC_32
[<27e266a4>] (spi_sync+0xc8/0xdc) from [<27e2675c>] (spi_write_then_read+0xa4/0xac)
[<27e2675c>] (spi_write_then_read+0xa4/0xac) from [<27e438e4>] (do_spi+0x288/0x3e8)
[<27e438e4>] (do_spi+0x288/0x3e8) from [<27e05c38>] (execute_command+0x3c/0x80)
[<27e05c38>] (execute_command+0x3c/0x80) from [<27e0ee48>] (run_list_real+0x9a8/0xad8)
[<27e0ee48>] (run_list_real+0x9a8/0xad8) from [<27e0e2b4>] (parse_stream_outer+0x138/0x200)
[<27e0e2b4>] (parse_stream_outer+0x138/0x200) from [<27e0f180>] (run_shell+0x5c/0x90)
[<27e0f180>] (run_shell+0x5c/0x90) from [<27e018b4>] (run_init+0x108/0x288)
[<27e018b4>] (run_init+0x108/0x288) from [<27e01a8c>] (start_barebox+0x58/0xb4)
[<27e01a8c>] (start_barebox+0x58/0xb4) from [<27e5ee18>] (barebox_non_pbl_start+0xc8/0xe0)
[<27e5ee18>] (barebox_non_pbl_start+0xc8/0xe0) from [<27e00004>] (__bare_init_start+0x0/0x10)

Signed-off-by: Alexander Shiyan <eagle.alexander923@gmail.com>
---
 drivers/spi/spi.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index c627d88954..c354c00e72 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -357,6 +357,9 @@ int spi_sync(struct spi_device *spi, struct spi_message *message)
 	int status;
 	int ret;
 
+	if (!spi->controller->transfer)
+		return -ENOTSUPP;
+
 	status = __spi_validate(spi, message);
 	if (status != 0)
 		return status;
-- 
2.39.1

Re: [PATCH] spi: Fix hang on spi_sync() when driver does not support transfer() call

[Sascha Hauer]

On Fri, 10 Jan 2025 10:50:10 +0300, Alexander Shiyan wrote:
> When a driver does not support transfer() call, such as most QSPI drivers,
> calling spi_sync() (e.g. with the "spi" command) will cause the system
> to hang. Fix this by adding a function check.
> 
> barebox@Mega-Milas Informer SAMA5D2:/ spi -b 1 -c 0 0xaa
> prefetch abort
> pc : [<00000004>]    lr : [<27e266a4>]
> sp : 27ff7c78  ip : 27ff7ce8  fp : 27e87410
> r10: 27ff7d20  r9 : 00000000  r8 : 23f58128
> r7 : 23f33c30  r6 : 27ff7c90  r5 : 27ff7d20  r4 : 27ff7c7c
> r3 : 00000000  r2 : 27ff7cc4  r1 : 27ff7c90  r0 : 27ff7d20
> Flags: nzCv  IRQs off  FIQs off  Mode SVC_32
> [<27e266a4>] (spi_sync+0xc8/0xdc) from [<27e2675c>] (spi_write_then_read+0xa4/0xac)
> [<27e2675c>] (spi_write_then_read+0xa4/0xac) from [<27e438e4>] (do_spi+0x288/0x3e8)
> [<27e438e4>] (do_spi+0x288/0x3e8) from [<27e05c38>] (execute_command+0x3c/0x80)
> [<27e05c38>] (execute_command+0x3c/0x80) from [<27e0ee48>] (run_list_real+0x9a8/0xad8)
> [<27e0ee48>] (run_list_real+0x9a8/0xad8) from [<27e0e2b4>] (parse_stream_outer+0x138/0x200)
> [<27e0e2b4>] (parse_stream_outer+0x138/0x200) from [<27e0f180>] (run_shell+0x5c/0x90)
> [<27e0f180>] (run_shell+0x5c/0x90) from [<27e018b4>] (run_init+0x108/0x288)
> [<27e018b4>] (run_init+0x108/0x288) from [<27e01a8c>] (start_barebox+0x58/0xb4)
> [<27e01a8c>] (start_barebox+0x58/0xb4) from [<27e5ee18>] (barebox_non_pbl_start+0xc8/0xe0)
> [<27e5ee18>] (barebox_non_pbl_start+0xc8/0xe0) from [<27e00004>] (__bare_init_start+0x0/0x10)
> 
> [...]

Applied, thanks!

[1/1] spi: Fix hang on spi_sync() when driver does not support transfer() call
      https://git.pengutronix.de/cgit/barebox/commit/?id=0b1be52382e9 (link may not be stable)

Best regards,
-- 
Sascha Hauer <s.hauer@pengutronix.de>