[PATCH for-7.1] hw/misc/grlib_ahb_apb_pnp: Support 8 and 16 bit accesses

[Peter Maydell <peter.maydell@linaro.org>]

In real hardware, the APB and AHB PNP data tables can be accessed
with byte and halfword reads as well as word reads.  Our
implementation currently only handles word reads.  Add support for
the 8 and 16 bit accesses.  Note that we only need to handle aligned
accesses -- unaligned accesses should continue to trap, as happens on
hardware.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1132
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
It would be nice if we could just set the .valid.min_access_size in
the MemoryRegionOps to 1 and have the memory system core synthesize
the 1 and 2 byte accesses from a 4 byte read, but currently that
doesn't work (see various past mailing list threads).
---
 hw/misc/grlib_ahb_apb_pnp.c | 10 ++++++----
 hw/misc/trace-events        |  4 ++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/hw/misc/grlib_ahb_apb_pnp.c b/hw/misc/grlib_ahb_apb_pnp.c
index 43e001c3c7b..5b05f158592 100644
--- a/hw/misc/grlib_ahb_apb_pnp.c
+++ b/hw/misc/grlib_ahb_apb_pnp.c
@@ -136,7 +136,8 @@ static uint64_t grlib_ahb_pnp_read(void *opaque, hwaddr offset, unsigned size)
     uint32_t val;
 
     val = ahb_pnp->regs[offset >> 2];
-    trace_grlib_ahb_pnp_read(offset, val);
+    val = extract32(val, (4 - (offset & 3) - size) * 8, size * 8);
+    trace_grlib_ahb_pnp_read(offset, size, val);
 
     return val;
 }
@@ -152,7 +153,7 @@ static const MemoryRegionOps grlib_ahb_pnp_ops = {
     .write      = grlib_ahb_pnp_write,
     .endianness = DEVICE_BIG_ENDIAN,
     .impl = {
-        .min_access_size = 4,
+        .min_access_size = 1,
         .max_access_size = 4,
     },
 };
@@ -247,7 +248,8 @@ static uint64_t grlib_apb_pnp_read(void *opaque, hwaddr offset, unsigned size)
     uint32_t val;
 
     val = apb_pnp->regs[offset >> 2];
-    trace_grlib_apb_pnp_read(offset, val);
+    val = extract32(val, (4 - (offset & 3) - size) * 8, size * 8);
+    trace_grlib_apb_pnp_read(offset, size, val);
 
     return val;
 }
@@ -263,7 +265,7 @@ static const MemoryRegionOps grlib_apb_pnp_ops = {
     .write      = grlib_apb_pnp_write,
     .endianness = DEVICE_BIG_ENDIAN,
     .impl = {
-        .min_access_size = 4,
+        .min_access_size = 1,
         .max_access_size = 4,
     },
 };
diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index 4d51a80de1d..c18bc0605e8 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -247,8 +247,8 @@ via1_adb_poll(uint8_t data, const char *vadbint, int status, int index, int size
 via1_auxmode(int mode) "setting auxmode to %d"
 
 # grlib_ahb_apb_pnp.c
-grlib_ahb_pnp_read(uint64_t addr, uint32_t value) "AHB PnP read addr:0x%03"PRIx64" data:0x%08x"
-grlib_apb_pnp_read(uint64_t addr, uint32_t value) "APB PnP read addr:0x%03"PRIx64" data:0x%08x"
+grlib_ahb_pnp_read(uint64_t addr, unsigned size, uint32_t value) "AHB PnP read addr:0x%03"PRIx64" size:%u data:0x%08x"
+grlib_apb_pnp_read(uint64_t addr, unsigned size, uint32_t value) "APB PnP read addr:0x%03"PRIx64" size:%u data:0x%08x"
 
 # led.c
 led_set_intensity(const char *color, const char *desc, uint8_t intensity_percent) "LED desc:'%s' color:%s intensity: %u%%"
-- 
2.25.1