Re: some progress with radeon on C8000

[Thomas Bogendoerfer <tsbogend@alpha.franken.de>]

On Sat, Sep 28, 2019 at 11:44:36PM +0200, Sven Schnelle wrote:
> Hi List,
> 
> i've spent quite some time this evening debugging why the Fire GL
> doesn't work in my C8000. As reading debug output didn't give me
> much insights, i decided to throw some Hardware at the Problem and
> connect a Logic Analyzer to the C8000. For that i switched to an old
> PCI Radeon 7000 which shows the same ring test failure.

below patch (with debug print left in) got PCI radeon working for me, when
I played with it last time.  The added fdc is a real fix, while the change
in parisc_agp_mask_memory is just a hack. The big problem there is to get
virtual address where the memory is mapped to in user space...

Thomas.


diff --git a/drivers/char/agp/parisc-agp.c b/drivers/char/agp/parisc-agp.c
index 15f2e7025b78..756bc4a265d9 100644
--- a/drivers/char/agp/parisc-agp.c
+++ b/drivers/char/agp/parisc-agp.c
@@ -20,6 +20,7 @@
 #include <linux/agp_backend.h>
 #include <linux/log2.h>
 #include <linux/slab.h>
+#include <linux/pagemap.h>
 
 #include <asm/parisc-device.h>
 #include <asm/ropes.h>
@@ -162,6 +163,16 @@ parisc_agp_insert_memory(struct agp_memory *mem, off_t pg_start, int type)
 			info->gatt[j] =
 				parisc_agp_mask_memory(agp_bridge,
 					paddr, type);
+			asm volatile("fdc %%r0(%0)" : : "r" (&info->gatt[j]));
+#if 0
+#if 0
+			printk("i %x j %lx page %p va %lx  paddr %lx gatt %lx\n",
+			       i, j, mem->pages[i], __va(paddr), paddr, info->gatt[j]);
+#else
+			printk("i %x j %lx page %p va %lx  paddr %lx\n",
+			       i, j, mem->pages[i], __va(paddr), paddr);
+#endif
+#endif
 		}
 	}
 
@@ -184,7 +195,7 @@ parisc_agp_remove_memory(struct agp_memory *mem, off_t pg_start, int type)
 	io_pg_start = info->io_pages_per_kpage * pg_start;
 	io_pg_count = info->io_pages_per_kpage * mem->page_count;
 	for (i = io_pg_start; i < io_pg_count + io_pg_start; i++) {
-		info->gatt[i] = agp_bridge->scratch_page;
+		// info->gatt[i] = agp_bridge->scratch_page;
 	}
 
 	agp_bridge->driver->tlb_flush(mem);
@@ -195,7 +206,22 @@ static unsigned long
 parisc_agp_mask_memory(struct agp_bridge_data *bridge, dma_addr_t addr,
 		       int type)
 {
-	return SBA_PDIR_VALID_BIT | addr;
+#if 1
+	u64 pa;
+	register unsigned ci; /* coherent index */
+	
+	pa = addr & IOVP_MASK;
+	mtsp(0,1);
+	asm("lci 0(%%sr1, %1), %0" : "=r" (ci) : "r" (__va(pa)));
+	
+	pa |= (ci >> PAGE_SHIFT) & 0xff;  /* move CI (8 bits) into lowest byte */
+
+	pa |= SBA_PDIR_VALID_BIT;	/* set "valid" bit */
+
+	return cpu_to_le64(pa);
+#else
+	return cpu_to_le64(SBA_PDIR_VALID_BIT | addr);
+#endif
 }
 
 static void

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]