diff mbox series

[v2,7/7] hw/arm/exynos4210: Connect serial port DMA busy signals with pl330

Message ID 20200118164229.22539-8-linux@roeck-us.net (mailing list archive)
State New, archived
Headers show
Series Fix Exynos4210 DMA support | expand

Commit Message

Guenter Roeck Jan. 18, 2020, 4:42 p.m. UTC 
The Exynos4210 serial driver uses an interrupt line to signal if receive
data is available. Connect that interrupt with the DMA controller's
'peripheral busy' gpio pin to stop the DMA if there is no more receive
data available. Without this patch, receive DMA runs wild and fills the
entire receive DMA buffer with invalid data. 

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Context changes; improved description
    This patch has an outstanding review comment, suggesting that
    uart and pl330 device states should be kept in Exynos4210State.
    I did not address this comment for a number of reasons.
    It looks like the problem is hypothetical, the problem may
    apply to all devices created in exynos4210_realize(), and I am
    not sure I understand what would need to be done to fix
    the problem for good (ie for all devices created in the same
    function which have the same problem). Overall, I think that
    handling this situation would be better left for a separate patch.

 hw/arm/exynos4210.c | 42 +++++++++++++++++++++++++++++-------------
 1 file changed, 29 insertions(+), 13 deletions(-)

Comments

Peter Maydell Jan. 20, 2020, 1:59 p.m. UTC | #1 
On Sat, 18 Jan 2020 at 16:42, Guenter Roeck <linux@roeck-us.net> wrote:
>
> The Exynos4210 serial driver uses an interrupt line to signal if receive
> data is available. Connect that interrupt with the DMA controller's
> 'peripheral busy' gpio pin to stop the DMA if there is no more receive
> data available. Without this patch, receive DMA runs wild and fills the
> entire receive DMA buffer with invalid data.
>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> v2: Context changes; improved description
>     This patch has an outstanding review comment, suggesting that
>     uart and pl330 device states should be kept in Exynos4210State.
>     I did not address this comment for a number of reasons.
>     It looks like the problem is hypothetical, the problem may
>     apply to all devices created in exynos4210_realize(), and I am
>     not sure I understand what would need to be done to fix
>     the problem for good (ie for all devices created in the same
>     function which have the same problem). Overall, I think that
>     handling this situation would be better left for a separate patch.
>
>  hw/arm/exynos4210.c | 42 +++++++++++++++++++++++++++++-------------
>  1 file changed, 29 insertions(+), 13 deletions(-)

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
diff mbox series

Patch

diff --git a/hw/arm/exynos4210.c b/hw/arm/exynos4210.c
index 76c0e2a3e8..6b050bb5c9 100644
--- a/hw/arm/exynos4210.c
+++ b/hw/arm/exynos4210.c
@@ -166,8 +166,8 @@  static uint64_t exynos4210_calc_affinity(int cpu)
     return (0x9 << ARM_AFF1_SHIFT) | cpu;
 }
 
-static void pl330_create(uint32_t base, qemu_or_irq *orgate, qemu_irq irq,
-                         int nreq, int nevents, int width)
+static DeviceState *pl330_create(uint32_t base, qemu_or_irq *orgate,
+                                 qemu_irq irq, int nreq, int nevents, int width)
 {
     SysBusDevice *busdev;
     DeviceState *dev;
@@ -196,6 +196,7 @@  static void pl330_create(uint32_t base, qemu_or_irq *orgate, qemu_irq irq,
         sysbus_connect_irq(busdev, i, qdev_get_gpio_in(DEVICE(orgate), i));
     }
     qdev_connect_gpio_out(DEVICE(orgate), 0, irq);
+    return dev;
 }
 
 static void exynos4210_realize(DeviceState *socdev, Error **errp)
@@ -204,7 +205,7 @@  static void exynos4210_realize(DeviceState *socdev, Error **errp)
     MemoryRegion *system_mem = get_system_memory();
     qemu_irq gate_irq[EXYNOS4210_NCPUS][EXYNOS4210_IRQ_GATE_NINPUTS];
     SysBusDevice *busdev;
-    DeviceState *dev;
+    DeviceState *dev, *uart[4], *pl330[3];
     int i, n;
 
     for (n = 0; n < EXYNOS4210_NCPUS; n++) {
@@ -390,19 +391,19 @@  static void exynos4210_realize(DeviceState *socdev, Error **errp)
 
 
     /*** UARTs ***/
-    exynos4210_uart_create(EXYNOS4210_UART0_BASE_ADDR,
+    uart[0] = exynos4210_uart_create(EXYNOS4210_UART0_BASE_ADDR,
                            EXYNOS4210_UART0_FIFO_SIZE, 0, serial_hd(0),
                   s->irq_table[exynos4210_get_irq(EXYNOS4210_UART_INT_GRP, 0)]);
 
-    exynos4210_uart_create(EXYNOS4210_UART1_BASE_ADDR,
+    uart[1] = exynos4210_uart_create(EXYNOS4210_UART1_BASE_ADDR,
                            EXYNOS4210_UART1_FIFO_SIZE, 1, serial_hd(1),
                   s->irq_table[exynos4210_get_irq(EXYNOS4210_UART_INT_GRP, 1)]);
 
-    exynos4210_uart_create(EXYNOS4210_UART2_BASE_ADDR,
+    uart[2] = exynos4210_uart_create(EXYNOS4210_UART2_BASE_ADDR,
                            EXYNOS4210_UART2_FIFO_SIZE, 2, serial_hd(2),
                   s->irq_table[exynos4210_get_irq(EXYNOS4210_UART_INT_GRP, 2)]);
 
-    exynos4210_uart_create(EXYNOS4210_UART3_BASE_ADDR,
+    uart[3] = exynos4210_uart_create(EXYNOS4210_UART3_BASE_ADDR,
                            EXYNOS4210_UART3_FIFO_SIZE, 3, serial_hd(3),
                   s->irq_table[exynos4210_get_irq(EXYNOS4210_UART_INT_GRP, 3)]);
 
@@ -450,12 +451,27 @@  static void exynos4210_realize(DeviceState *socdev, Error **errp)
             s->irq_table[exynos4210_get_irq(28, 3)]);
 
     /*** DMA controllers ***/
-    pl330_create(EXYNOS4210_PL330_BASE0_ADDR, &s->pl330_irq_orgate[0],
-                 s->irq_table[exynos4210_get_irq(21, 0)], 32, 30, 32);
-    pl330_create(EXYNOS4210_PL330_BASE1_ADDR, &s->pl330_irq_orgate[1],
-                 s->irq_table[exynos4210_get_irq(21, 1)], 32, 30, 32);
-    pl330_create(EXYNOS4210_PL330_BASE2_ADDR, &s->pl330_irq_orgate[2],
-                 s->irq_table[exynos4210_get_irq(20, 1)], 1, 30, 64);
+    pl330[0] = pl330_create(EXYNOS4210_PL330_BASE0_ADDR,
+                            &s->pl330_irq_orgate[0],
+                            s->irq_table[exynos4210_get_irq(21, 0)],
+                            32, 30, 32);
+    pl330[1] = pl330_create(EXYNOS4210_PL330_BASE1_ADDR,
+                            &s->pl330_irq_orgate[1],
+                            s->irq_table[exynos4210_get_irq(21, 1)],
+                            32, 30, 32);
+    pl330[2] = pl330_create(EXYNOS4210_PL330_BASE2_ADDR,
+                            &s->pl330_irq_orgate[2],
+                            s->irq_table[exynos4210_get_irq(20, 1)],
+                            1, 30, 64);
+
+    sysbus_connect_irq(SYS_BUS_DEVICE(uart[0]), 1,
+                       qdev_get_gpio_in(pl330[0], 15));
+    sysbus_connect_irq(SYS_BUS_DEVICE(uart[1]), 1,
+                       qdev_get_gpio_in(pl330[1], 15));
+    sysbus_connect_irq(SYS_BUS_DEVICE(uart[2]), 1,
+                       qdev_get_gpio_in(pl330[0], 17));
+    sysbus_connect_irq(SYS_BUS_DEVICE(uart[3]), 1,
+                       qdev_get_gpio_in(pl330[1], 17));
 }
 
 static void exynos4210_init(Object *obj)