[1/6] pata_cypress: add a module option to disable BM-DMA

Commit Message

Christoph Hellwig June 16, 2021, 1:46 p.m. UTC

Multiple users report that they need to disable DMA on this driver,
so provide an option to do so without affecting all of libata.

Signed-off-by: Christoph Hellwig <[e-mail]>
---
 drivers/ata/pata_cypress.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

Comments

Russell King (Oracle) June 16, 2021, 2:16 p.m. UTC | #1

On Wed, Jun 16, 2021 at 03:46:53PM +0200, Christoph Hellwig wrote:
> Multiple users report that they need to disable DMA on this driver,
> so provide an option to do so without affecting all of libata.
> 
> Signed-off-by: Christoph Hellwig <[e-mail]>

Thanks!

Reviewed-by: Russell King (Oracle) <[e-mail]>

Patch

diff --git a/drivers/ata/pata_cypress.c b/drivers/ata/pata_cypress.c
index e1486fe298ae..5b3a7a8ebef6 100644
--- a/drivers/ata/pata_cypress.c
+++ b/drivers/ata/pata_cypress.c
@@ -41,6 +41,10 @@  enum {
 	CY82_INDEX_TIMEOUT	= 0x32
 };
 
+static bool enable_dma = true;
+module_param(enable_dma, bool, 0);
+MODULE_PARM_DESC(enable_dma, "Enable bus master DMA operations");
+
 /**
  *	cy82c693_set_piomode	-	set initial PIO mode data
  *	@ap: ATA interface
@@ -124,14 +128,16 @@  static struct ata_port_operations cy82c693_port_ops = {
 
 static int cy82c693_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
 {
-	static const struct ata_port_info info = {
+	static struct ata_port_info info = {
 		.flags = ATA_FLAG_SLAVE_POSS,
 		.pio_mask = ATA_PIO4,
-		.mwdma_mask = ATA_MWDMA2,
 		.port_ops = &cy82c693_port_ops
 	};
 	const struct ata_port_info *ppi[] = { &info, &ata_dummy_port_info };
 
+	if (enable_dma)
+		info.mwdma_mask = ATA_MWDMA2;
+
 	/* Devfn 1 is the ATA primary. The secondary is magic and on devfn2.
 	   For the moment we don't handle the secondary. FIXME */