On Tue, 2024-02-27 at 18:38 -0800, Kuppuswamy Sathyanarayanan wrote:
>
> On 2/27/24 4:00 PM, David E. Box wrote:
> > The current mailbox commands are either read-only or write-only and the
> > flow is different for each. New commands will need to send and receive
> > data. In preparation for these commands, create a common polling function
> > to handle sending data and receiving in the same transaction.
> >
> > Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
> > ---
> >
> > V2 - In sdsi_cmd_read() remove unnecessary check for non-zero packet_size
> > in do loop since the loop is exited earlier when packet_size is
> > zero.
> >
> > drivers/platform/x86/intel/sdsi.c | 79 +++++++++++++++++--------------
> > 1 file changed, 44 insertions(+), 35 deletions(-)
> >
> > diff --git a/drivers/platform/x86/intel/sdsi.c
> > b/drivers/platform/x86/intel/sdsi.c
> > index a70c071de6e2..d80c2dc0ce71 100644
> > --- a/drivers/platform/x86/intel/sdsi.c
> > +++ b/drivers/platform/x86/intel/sdsi.c
> > @@ -15,6 +15,7 @@
> > #include <linux/iopoll.h>
> > #include <linux/kernel.h>
> > #include <linux/module.h>
> > +#include <linux/overflow.h>
> > #include <linux/pci.h>
> > #include <linux/slab.h>
> > #include <linux/sysfs.h>
> > @@ -156,8 +157,8 @@ static int sdsi_status_to_errno(u32 status)
> > }
> > }
> >
> > -static int sdsi_mbox_cmd_read(struct sdsi_priv *priv, struct sdsi_mbox_info
> > *info,
> > - size_t *data_size)
> > +static int sdsi_mbox_poll(struct sdsi_priv *priv, struct sdsi_mbox_info
> > *info,
> > + size_t *data_size)
> > {
> > struct device *dev = priv->dev;
> > u32 total, loop, eom, status, message_size;
> > @@ -166,18 +167,10 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv,
> > struct sdsi_mbox_info *inf
> >
> > lockdep_assert_held(&priv->mb_lock);
> >
> > - /* Format and send the read command */
> > - control = FIELD_PREP(CTRL_EOM, 1) |
> > - FIELD_PREP(CTRL_SOM, 1) |
> > - FIELD_PREP(CTRL_RUN_BUSY, 1) |
> > - FIELD_PREP(CTRL_PACKET_SIZE, info->size);
> > - writeq(control, priv->control_addr);
> > -
> > /* For reads, data sizes that are larger than the mailbox size are
> > read in packets. */
> > total = 0;
> > loop = 0;
> > do {
> > - void *buf = info->buffer + (SDSI_SIZE_MAILBOX * loop);
> > u32 packet_size;
> >
> > /* Poll on ready bit */
> > @@ -195,6 +188,11 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv,
> > struct sdsi_mbox_info *inf
> > if (ret)
> > break;
> >
> > + if (!packet_size) {
> > + sdsi_complete_transaction(priv);
> > + break;
> > + }
> > +
> > /* Only the last packet can be less than the mailbox size.
> > */
> > if (!eom && packet_size != SDSI_SIZE_MAILBOX) {
> > dev_err(dev, "Invalid packet size\n");
> > @@ -208,9 +206,13 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv,
> > struct sdsi_mbox_info *inf
> > break;
> > }
> >
> > - sdsi_memcpy64_fromio(buf, priv->mbox_addr,
> > round_up(packet_size, SDSI_SIZE_CMD));
> > + if (info->buffer) {
> > + void *buf = info->buffer +
> > array_size(SDSI_SIZE_MAILBOX, loop);
> >
> > - total += packet_size;
> > + sdsi_memcpy64_fromio(buf, priv->mbox_addr,
> > + round_up(packet_size,
> > SDSI_SIZE_CMD));
> > + total += packet_size;
> > + }
> >
> > sdsi_complete_transaction(priv);
> > } while (!eom && ++loop < MBOX_MAX_PACKETS);
> > @@ -230,16 +232,33 @@ static int sdsi_mbox_cmd_read(struct sdsi_priv *priv,
> > struct sdsi_mbox_info *inf
> > dev_warn(dev, "Read count %u differs from expected count
> > %u\n",
> > total, message_size);
> >
> > - *data_size = total;
> > + if (data_size)
> > + *data_size = total;
> >
>
> Is there a chance for it to be NULL with current callers?
Yes. Write only callers set this to NULL.
David
