Re: [PATCH v3 5/8] hw/ide/ahci: PxSACT and PxCI is cleared when PxCMD.ST is cleared

[Philippe Mathieu-Daudé]

On 9/6/23 16:08, Niklas Cassel wrote:

From: Niklas Cassel 

According to AHCI 1.3.1 definition of PxSACT:
This field is cleared when PxCMD.ST is written from a '1' to a '0' by
software. This field is not cleared by a COMRESET or a software reset.


Interesting, since its origin in commit f6ad2e32f8 ("ahci: add ahci
emulation") PxSACT is reset unconditionally in ahci_reset_port().

As for this patch:
Reviewed-by: Philippe Mathieu-Daudé 


According to AHCI 1.3.1 definition of PxCI:
This field is also cleared when PxCMD.ST is written from a '1' to a '0'
by software.

Clearing PxCMD.ST is part of the error recovery procedure, see
AHCI 1.3.1, section "6.2 Error Recovery".

If we don't clear PxCI on error recovery, the previous command will
incorrectly still be marked as pending after error recovery.

Signed-off-by: Niklas Cassel 
---
  hw/ide/ahci.c | 5 +
  1 file changed, 5 insertions(+)

[PATCH v3 5/8] hw/ide/ahci: PxSACT and PxCI is cleared when PxCMD.ST is cleared

[Niklas Cassel]

From: Niklas Cassel 

According to AHCI 1.3.1 definition of PxSACT:
This field is cleared when PxCMD.ST is written from a '1' to a '0' by
software. This field is not cleared by a COMRESET or a software reset.

According to AHCI 1.3.1 definition of PxCI:
This field is also cleared when PxCMD.ST is written from a '1' to a '0'
by software.

Clearing PxCMD.ST is part of the error recovery procedure, see
AHCI 1.3.1, section "6.2 Error Recovery".

If we don't clear PxCI on error recovery, the previous command will
incorrectly still be marked as pending after error recovery.

Signed-off-by: Niklas Cassel 
---
 hw/ide/ahci.c | 5 +
 1 file changed, 5 insertions(+)

diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 3deaf01add..a31e6fa65e 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -329,6 +329,11 @@ static void ahci_port_write(AHCIState *s, int port, int 
offset, uint32_t val)
 ahci_check_irq(s);
 break;
 case AHCI_PORT_REG_CMD:
+if ((pr->cmd & PORT_CMD_START) && !(val & PORT_CMD_START)) {
+pr->scr_act = 0;
+pr->cmd_issue = 0;
+}
+
 /* Block any Read-only fields from being set;
  * including LIST_ON and FIS_ON.
  * The spec requires to set ICC bits to zero after the ICC change
-- 
2.40.1