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nxp/lpc55s36: failure reading from internal Flash via flash_read() #80325

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pillo79 opened this issue Oct 23, 2024 · 0 comments · Fixed by #80351
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nxp/lpc55s36: failure reading from internal Flash via flash_read() #80325

pillo79 opened this issue Oct 23, 2024 · 0 comments · Fixed by #80351
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@mmahadevan108 @dleach02
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area: Flash bug The issue is a bug, or the PR is fixing a bug platform: NXP Drivers NXP Semiconductors, drivers platform: NXP NXP priority: low Low impact/importance bug

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@pillo79
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pillo79 commented Oct 23, 2024 •
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Describe the bug

I am having trouble reading from internal Flash on the LPC55S36 on current main.
I traced the issue from flash_read(addr, len) to flash_mcux_read(addr, len) calling the NXP HAL function FLASH_IsFlashAreaReadable, which jumps to an hardcoded ROM/bootloader function address (which is sadly not accessible by the debug probe) and in a few instructions to the given addr, causing a panic.

To Reproduce

This is reproducible on my end building and running the unmodified samples/drivers/flash_shell sample on an LPCXpresso55S36 eval board:

west build -p -b lpcxpresso55s36 samples/drivers/flash_shell/
west flash -r linkserver

Executing flash read flash-controller@34000 0 1 on the uart console that pops up triggers a fault at address 0 and crashes Zephyr.

Expected behavior
A proper Flash read on this SOC.

Note that a quick test of replacing the body of flash_mcux_read with a simple FLASH_Read() HAL API call results in the expected behavior, including detection of non-available pages.

Impact
Blocker for Flash API access on this platform.

Logs and console output
Running a valid command on the flash_shell sample shows the following console output:

Flash shell sample
*** Booting Zephyr OS build v3.7.0-4863-g185432c96dd7 ***
uart:~$ flash read flash-controller@34000 0 1
[00:00:09.488,000] <err> os: ***** USAGE FAULT *****
[00:00:09.488,000] <err> os:   Illegal use of the EPSR
[00:00:09.488,000] <err> os: r0/a1:  0x00000076  r1/a2:  0x40000000  r2/a3:  0x00000001
[00:00:09.488,000] <err> os: r3/a4:  0x13028c41 r12/ip:  0x0000bf4d r14/lr:  0x0000bf69
[00:00:09.488,000] <err> os:  xpsr:  0x80000000
[00:00:09.488,000] <err> os: Faulting instruction address (r15/pc): 0x00000000
[00:00:09.488,000] <err> os: >>> ZEPHYR FATAL ERROR 35: Unknown error on CPU 0
[00:00:09.488,000] <err> os: Current thread: 0x20000630 (shell_uart)
[00:00:09.551,000] <err> os: Halting system

Note the Faulting instruction address (r15/pc): 0x00000000 changes to mimic the requested address (0 in the command above). E.g. flash read flash-controller@34000 0x1234 4 results in Faulting instruction address (r15/pc): 0x00001234

The backtrace as I could capture is:

#0  z_arm_usage_fault () at zephyr/arch/arm/core/cortex_m/fault_s.S:80
#1  <signal handler called>
#2  thread_valid_cb (cthread=0x76 <_irq_vector_table+54>, user_data=0x40000000) at zephyr/subsys/shell/modules/kernel_service/thread/thread.c:31
#3  0x0000bf68 in flash_mcux_read (dev=<optimized out>, offset=<optimized out>, data=0x20009d2c <shell_uart_stack+1628>, len=23567)
    at zephyr/drivers/flash/soc_flash_mcux.c:210
#4  0x0000d7d4 in shell_uart_backend ()

(thread_valid_cb is the symbol closest to address 0 AFAICS).

Environment (please complete the following information):

  • OS: Linux
  • Toolchain: Zephyr SDK 0.16.8
  • Commit SHA: 185432c96dd7
@pillo79 pillo79 added bug The issue is a bug, or the PR is fixing a bug area: Flash platform: NXP NXP labels Oct 23, 2024
@pillo79 pillo79 mentioned this issue Oct 24, 2024
Merged
@pillo79 pillo79 added the platform: NXP Drivers NXP Semiconductors, drivers label Oct 25, 2024
@mmahadevan108 mmahadevan108 added the priority: low Low impact/importance bug label Oct 29, 2024
pillo79 added a commit to pillo79/zephyr that referenced this issue Nov 5, 2024
@pillo79
drivers/flash/mcux: fix flash_read() operation on LPC55S36
9d78c65 
As other targets in the LPC55xxx series, the LPC55S36 has a Flash
controller that raises ECC errors when reading erased pages directly.
To avoid this, there is special code for this platform that calls the
HAL FLASH_IsFlashAreaReadable() function. However, this in turn calls a
function at an hardcoded address in ROM that _always_ causes an
instruction fault, making the situation worse.

This patch reworks the read operation to use the FLASH_Read() HAL
function for this target to gracefully handle error conditions and
properly emulate accesses to erased pages. The preprocessor is required
since some targets do not define the FLASH_Read() function.

Fixes: zephyrproject-rtos#80325

Signed-off-by: Luca Burelli <[email protected]>
pillo79 added a commit to pillo79/zephyr that referenced this issue Nov 7, 2024
@pillo79
drivers/flash/mcux: fix flash_read() operation on LPC55S36
f007763 
As other targets in the LPC55xxx series, the LPC55S36 has a Flash
controller that raises ECC errors when reading erased pages directly.
To avoid this, there is special code for this platform that calls the
HAL FLASH_IsFlashAreaReadable() function. However, this in turn calls a
function at an hardcoded address in ROM that _always_ causes an
instruction fault, making the situation worse.

This patch reworks the verify operation to use the FLASH_VerifyErased()
HAL function for this target to gracefully handle error conditions and
properly emulate accesses to erased pages. The preprocessor is required
since some targets do not define the FLASH_VerifyErased() function.

Fixes: zephyrproject-rtos#80325

Signed-off-by: Luca Burelli <[email protected]>
mmahadevan108 pushed a commit that referenced this issue Nov 7, 2024
@pillo79 @mmahadevan108
drivers/flash/mcux: fix flash_read() operation on LPC55S36
20cd3a3 
As other targets in the LPC55xxx series, the LPC55S36 has a Flash
controller that raises ECC errors when reading erased pages directly.
To avoid this, there is special code for this platform that calls the
HAL FLASH_IsFlashAreaReadable() function. However, this in turn calls a
function at an hardcoded address in ROM that _always_ causes an
instruction fault, making the situation worse.

This patch reworks the read operation to use the FLASH_Read() HAL
function for this target to gracefully handle error conditions and
properly emulate accesses to erased pages. The preprocessor is required
since some targets do not define the FLASH_Read() function.

Fixes: #80325

Signed-off-by: Luca Burelli <[email protected]>
JA-NXP pushed a commit to nxp-upstream/zephyr that referenced this issue Nov 19, 2024
@pillo79 @JA-NXP
drivers/flash/mcux: fix flash_read() operation on LPC55S36
874c7bb 
As other targets in the LPC55xxx series, the LPC55S36 has a Flash
controller that raises ECC errors when reading erased pages directly.
To avoid this, there is special code for this platform that calls the
HAL FLASH_IsFlashAreaReadable() function. However, this in turn calls a
function at an hardcoded address in ROM that _always_ causes an
instruction fault, making the situation worse.

This patch reworks the read operation to use the FLASH_Read() HAL
function for this target to gracefully handle error conditions and
properly emulate accesses to erased pages. The preprocessor is required
since some targets do not define the FLASH_Read() function.

Fixes: zephyrproject-rtos#80325

Signed-off-by: Luca Burelli <[email protected]>
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@mmahadevan108 mmahadevan108

@dleach02 dleach02

Labels
area: Flash bug The issue is a bug, or the PR is fixing a bug platform: NXP Drivers NXP Semiconductors, drivers platform: NXP NXP priority: low Low impact/importance bug
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flash: fix flash_read API for NXP LPC55S36 pillo79/zephyr
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@pillo79 @mmahadevan108 @dleach02