Re: [PATCH net-next v2 2/4] net: ipa: use upper_32_bits()

On 3/18/21 11:03 AM, Florian Fainelli wrote:

On 3/18/2021 6:51 AM, Alex Elder wrote:

quoted

Use upper_32_bits() to extract the high-order 32 bits of a DMA
address.  This avoids doing a 32-position shift on a DMA address
if it happens not to be 64 bits wide.

Suggested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Alex Elder <redacted>
---
v2: - Switched to use the existing function, as suggested by Florian.

  drivers/net/ipa/gsi.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 2119367b93ea9..82c5a0d431ee5 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c

@@ -711,7 +711,7 @@ static void gsi_evt_ring_program(struct gsi *gsi, u32 evt_ring_id)
  	val = evt_ring->ring.addr & GENMASK(31, 0);

Did you want to introduce another patch to use lower_32_bits() for the
assignment above?

Bah... Yes, I should have done that.  I was really just
focused on the new function I created and didn't need
to.   I'll do as you suggest.

I'll also see if I do that anywhere else in the driver
and will use these functions as well if appropriate.

I'll do so in the same patch 2 of version 3.

Thanks Florian.

					-Alex

quoted

  	iowrite32(val, gsi->virt + GSI_EV_CH_E_CNTXT_2_OFFSET(evt_ring_id));
  
-	val = evt_ring->ring.addr >> 32;
+	val = upper_32_bits(evt_ring->ring.addr);
  	iowrite32(val, gsi->virt + GSI_EV_CH_E_CNTXT_3_OFFSET(evt_ring_id));
  
  	/* Enable interrupt moderation by setting the moderation delay */

@@ -819,7 +819,7 @@ static void gsi_channel_program(struct gsi_channel *channel, bool doorbell)
  	val = channel->tre_ring.addr & GENMASK(31, 0);

And likewise?

quoted

  	iowrite32(val, gsi->virt + GSI_CH_C_CNTXT_2_OFFSET(channel_id));
  
-	val = channel->tre_ring.addr >> 32;
+	val = upper_32_bits(channel->tre_ring.addr);
  	iowrite32(val, gsi->virt + GSI_CH_C_CNTXT_3_OFFSET(channel_id));
  
  	/* Command channel gets low weighted round-robin priority */