libata: Add the AHCI_HFLAG_NO_WRITE_TO_RO flag (7fab72f8) · Commits · 戴 / test

While most hardware will simply ignore a write to a read-only register, some hardware will signal an abort if this occurs. This commit introduces the flag AHCI_HFLAG_NO_WRITE_TO_RO to prevent the AHCI library from attempting to write to the HOST_CAP, HOST_CAP2, and HOST_PORTS_IMPL registers which may be read-only. Signed-off-by:

Doug Berger <opendmb@gmail.com> Signed-off-by:

Tejun Heo <tj@kernel.org>

drivers/ata/ahci.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -249,6 +249,8 @@ enum {
		#endif
		AHCI_HFLAG_WAKE_BEFORE_STOP = (1 << 22), /* wake before DMA stop */
		AHCI_HFLAG_YES_ALPM = (1 << 23), /* force ALPM cap on */
		AHCI_HFLAG_NO_WRITE_TO_RO = (1 << 24), /* don't write to read
		only registers */

		/* ap->flags bits */

drivers/ata/libahci.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -945,6 +945,7 @@ int ahci_reset_controller(struct ata_host *host)
		/* Some registers might be cleared on reset. Restore
		* initial values.
		*/
		if (!(hpriv->flags & AHCI_HFLAG_NO_WRITE_TO_RO))
		ahci_restore_initial_config(host);
		} else
		dev_info(host->dev, "skipping global host reset\n");

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