On 12/06/19 9:30 PM, Ralf Ramsauer wrote:


On 6/12/19 5:48 PM, Nikhil Devshatwar wrote:
On 24/05/19 4:15 AM, Ralf Ramsauer wrote:
Hi Lokesh,

On 5/23/19 11:16 PM, 'Nikhil Devshatwar' via Jailhouse wrote:
UART is disabled by default on TI platforms and must be enabled
on some platforms via the MDR register.
Do this as part of uart_init for 8250 driver

Signed-off-by: Nikhil Devshatwar <[email protected]>
Signed-off-by: Lokesh Vutla <[email protected]>
---
   inmates/lib/uart-8250.c | 4 ++++
   1 file changed, 4 insertions(+)

diff --git a/inmates/lib/uart-8250.c b/inmates/lib/uart-8250.c
index fb7940d2..42b0979c 100644
--- a/inmates/lib/uart-8250.c
+++ b/inmates/lib/uart-8250.c
@@ -49,6 +49,7 @@
   #define  UART_LCR_DLAB        0x80
   #define UART_LSR        0x5
   #define  UART_LSR_THRE        0x20
+#define  UART_MDR1        0x8
     static void reg_out_mmio32(struct uart_chip *chip, unsigned int
reg, u32 value)
   {
@@ -67,6 +68,9 @@ static void uart_8250_init(struct uart_chip *chip)
           chip->reg_out(chip, UART_DLL, chip->divider);
           chip->reg_out(chip, UART_DLM, 0);
           chip->reg_out(chip, UART_LCR, UART_LCR_8N1);
+#ifdef CONFIG_TI_16550_MDR_QUIRK

if (comm_region->console.flags & JAILHOUSE_CON_MDS_QUIRK)

+        chip->reg_out(chip, UART_MDR1, 0);
+#endif

I think it's better to encode this in struct uart's flags. We still have
some bits free there.

s/struct uart/struct jailhouse_console/

Oh okay.
Using console flag for setting up uart didn't sound right to me.
Here the inmate has a dedicated uart instance, not shared with the root cell.

If that's the preferred option, I'll do that.
Of course both uarts have the same behavior.

Nikhil D



I looked up in the source.
The flags are only for the console.
Here we need this to be written from the inmate, which doesn't know
about the console flags.

We do pass the flags to the inmate via the communication region. See
hypervisor/control.c:657. Just pick a reserved bit.

   Ralf

Which struct uart are you referring to?

Nikhil D


It's better to not reintroduce compile time switches, it took a while to
get rid of (most of) them.

    Ralf

       }
   }


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