Re: [PATCH kvmtool 05/21] hw/i8042: Clean up data types

[Andre Przywara <andre.przywara@arm.com>]

On Thu, 11 Feb 2021 16:55:43 +0000
Alexandru Elisei <alexandru.elisei@arm.com> wrote:

Hi,

> On 12/10/20 2:28 PM, Andre Przywara wrote:
> 
> > The i8042 is clearly an 8-bit era device, so there is little room for
> > 32-bit registers.
> > Clean up the data types used.
> >
> > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > ---
> >  hw/i8042.c | 20 ++++++++++----------
> >  1 file changed, 10 insertions(+), 10 deletions(-)
> >
> > diff --git a/hw/i8042.c b/hw/i8042.c
> > index 37a99a2d..36ee183f 100644
> > --- a/hw/i8042.c
> > +++ b/hw/i8042.c
> > @@ -64,11 +64,11 @@
> >  struct kbd_state {
> >  	struct kvm		*kvm;
> >  
> > -	char			kq[QUEUE_SIZE];	/* Keyboard queue */
> > +	u8			kq[QUEUE_SIZE];	/* Keyboard queue */
> >  	int			kread, kwrite;	/* Indexes into the queue */
> >  	int			kcount;		/* number of elements in queue */
> >  
> > -	char			mq[QUEUE_SIZE];
> > +	u8			mq[QUEUE_SIZE];
> >  	int			mread, mwrite;
> >  	int			mcount;  
> 
> I think the write_cmd field further down should also be u8 because it stores the
> first byte of a command (and it's set only to an 8 bit value in kbd_write_command()).

Yes, looks like it, will change it on the way. I guess I wanted to
suppress my rewrite-everything complex ;-)

If you allow, I will also fix the confusing indentation bug in the big
switch statement on the way.
 
> Otherwise, it looks ok to me. osdev wiki seems to confirm that the device is
> indeed 8 bit only, and all the registers are 8 bit now:
> 
> Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>

Thanks!
Andre

> 
> >  
> > @@ -173,9 +173,9 @@ static void kbd_write_command(struct kvm *kvm, u8 val)
> >  /*
> >   * Called when the OS reads from port 0x60 (PS/2 data)
> >   */
> > -static u32 kbd_read_data(void)
> > +static u8 kbd_read_data(void)
> >  {
> > -	u32 ret;
> > +	u8 ret;
> >  	int i;
> >  
> >  	if (state.kcount != 0) {
> > @@ -202,9 +202,9 @@ static u32 kbd_read_data(void)
> >  /*
> >   * Called when the OS read from port 0x64, the command port
> >   */
> > -static u32 kbd_read_status(void)
> > +static u8 kbd_read_status(void)
> >  {
> > -	return (u32)state.status;
> > +	return state.status;
> >  }
> >  
> >  /*
> > @@ -212,7 +212,7 @@ static u32 kbd_read_status(void)
> >   * Things written here are generally arguments to commands previously
> >   * written to port 0x64 and stored in state.write_cmd
> >   */
> > -static void kbd_write_data(u32 val)
> > +static void kbd_write_data(u8 val)
> >  {
> >  	switch (state.write_cmd) {
> >  	case I8042_CMD_CTL_WCTR:
> > @@ -304,8 +304,8 @@ static bool kbd_in(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void *
> >  		break;
> >  	}
> >  	case I8042_DATA_REG: {
> > -		u32 value = kbd_read_data();
> > -		ioport__write32(data, value);
> > +		u8 value = kbd_read_data();
> > +		ioport__write8(data, value);
> >  		break;
> >  	}
> >  	case I8042_PORT_B_REG: {
> > @@ -328,7 +328,7 @@ static bool kbd_out(struct ioport *ioport, struct kvm_cpu *vcpu, u16 port, void
> >  		break;
> >  	}
> >  	case I8042_DATA_REG: {
> > -		u32 value = ioport__read32(data);
> > +		u8 value = ioport__read8(data);
> >  		kbd_write_data(value);
> >  		break;
> >  	}  


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