[src/trunk]: src/sys/arch/hpcsh/dev/hd64461 Fix workaround for SH-3 PCMCIA bu...

[rin <rin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/215fa15bd47b
branches:  trunk
changeset: 989061:215fa15bd47b
user:      rin <rin%NetBSD.org@localhost>
date:      Mon Oct 11 02:30:00 2021 +0000

description:
Fix workaround for SH-3 PCMCIA bug in accordance with description
found in TECH I vol. 14 (CQ Publishing, Tokyo, 2002, in Japanese),
as well as experiment on real hardware:

Byte-access to area 6 becomes word-access (both CE1# and CE2# are
wrongly asserted), if preceding access is word-wise. Inserting a
dummy byte-access works around the problem. Area 5 is not affected.

Therefore,

(1) Insert a dummy byte-read before all byte-wise operations.

(2) Restrict the workaround to area 6 (channel 0), and rename
    fixup_sh3_pcmcia_area() to fixup_sh3_pcmcia_area6() for clarity.

Also, we used to use 0xba000000 (== HD64461_PCC0_IOBASE) as target
for the dummy read. However, this can modify device states, which
breaks ep(4) at least. Thus,

(3) Use HD64461_PCC0_MEMBASE as target for the dummy read. This is
    assigned to attribute memory space, and byte-read should be
    harmless.

diffstat:

 sys/arch/hpcsh/dev/hd64461/hd64461pcmcia.c |  50 ++++++++++++++++++++++-------
 1 files changed, 38 insertions(+), 12 deletions(-)

diffs (111 lines):

diff -r 6d7bc0835dd7 -r 215fa15bd47b sys/arch/hpcsh/dev/hd64461/hd64461pcmcia.c
--- a/sys/arch/hpcsh/dev/hd64461/hd64461pcmcia.c        Mon Oct 11 01:49:08 2021 +0000
+++ b/sys/arch/hpcsh/dev/hd64461/hd64461pcmcia.c        Mon Oct 11 02:30:00 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: hd64461pcmcia.c,v 1.54 2021/08/07 16:18:54 thorpej Exp $       */
+/*     $NetBSD: hd64461pcmcia.c,v 1.55 2021/10/11 02:30:00 rin Exp $   */
 
 /*-
  * Copyright (c) 2001, 2002, 2004 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: hd64461pcmcia.c,v 1.54 2021/08/07 16:18:54 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: hd64461pcmcia.c,v 1.55 2021/10/11 02:30:00 rin Exp $");
 
 #include "opt_hd64461pcmcia.h"
 
@@ -223,17 +223,37 @@
 #ifdef HD64461PCMCIA_DEBUG
 STATIC void hd64461pcmcia_info(struct hd64461pcmcia_softc *);
 #endif
-/* fix SH3 Area[56] bug */
-STATIC void fixup_sh3_pcmcia_area(bus_space_tag_t);
+
+/*
+ * Workaround for SH-3 PCMCIA bug on area 6:
+ *
+ * According to TECH I vol. 14 (CQ Publishing, Tokyo, 2002) p. 184,
+ * byte-access to area 6 becomes word-access if preceding access is
+ * word-wise. Inserting a dummy byte-access works around the problem.
+ * Area 5 is not affected by this bug.
+ *
+ * Therefore, we insert a dummy byte-wise read to HD64461_PCC0_MEMBASE
+ * before any byte-access to area 6 (channel 0).
+ *
+ * Note that we used to use HD64461_PCC0_IOBASE for this purpose. But,
+ * read access to that register can modify device states, which breaks
+ * ep(4) at least. On the other hand, since HD64461_PCC0_MEMBASE is
+ * assigned to attribute memory, read access should be harmless.
+ */
+STATIC void fixup_sh3_pcmcia_area6(bus_space_tag_t);
 #define        _BUS_SPACE_ACCESS_HOOK()                                        \
-do {                                                                   \
-       uint8_t dummy __attribute__((__unused__)) =                     \
-        *(volatile uint8_t *)0xba000000;                               \
-} while (/*CONSTCOND*/0)
+    do {                                                               \
+       uint8_t dummy __unused =                                        \
+           *(volatile uint8_t *)HD64461_PCC0_MEMBASE;                  \
+    } while (0)
+_BUS_SPACE_READ(_sh3_pcmcia_bug, 1, 8)
+_BUS_SPACE_READ_MULTI(_sh3_pcmcia_bug, 1, 8)
+_BUS_SPACE_READ_REGION(_sh3_pcmcia_bug, 1, 8)
 _BUS_SPACE_WRITE(_sh3_pcmcia_bug, 1, 8)
 _BUS_SPACE_WRITE_MULTI(_sh3_pcmcia_bug, 1, 8)
 _BUS_SPACE_WRITE_REGION(_sh3_pcmcia_bug, 1, 8)
 _BUS_SPACE_SET_MULTI(_sh3_pcmcia_bug, 1, 8)
+_BUS_SPACE_COPY_REGION(_sh3_pcmcia_bug, 1, 8)
 #undef _BUS_SPACE_ACCESS_HOOK
 
 #define        DELAY_MS(x)     delay((x) * 1000)
@@ -386,7 +406,8 @@
        bus_space_alloc(ch->ch_memt, 0, 0x00ffffff, 0x01000000,
            0x01000000, 0x01000000, 0, &ch->ch_membase_addr,
            &ch->ch_memh);
-       fixup_sh3_pcmcia_area(ch->ch_memt);
+       if (channel == CHANNEL_0)
+               fixup_sh3_pcmcia_area6(ch->ch_memt);
 
        /* Common memory space extent */
        ch->ch_memsize = 0x01000000;
@@ -394,7 +415,8 @@
                ch->ch_cmemt[i] = bus_space_create(0, "PCMCIA common memory",
                    membase + 0x01000000,
                    ch->ch_memsize);
-               fixup_sh3_pcmcia_area(ch->ch_cmemt[i]);
+               if (channel == CHANNEL_0)
+                       fixup_sh3_pcmcia_area6(ch->ch_cmemt[i]);
        }
 
        /* I/O port extent and interrupt staff */
@@ -406,7 +428,7 @@
                ch->ch_iot = bus_space_create(0, "PCMCIA I/O port",
                    HD64461_PCC0_IOBASE,
                    ch->ch_iosize);
-               fixup_sh3_pcmcia_area(ch->ch_iot);
+               fixup_sh3_pcmcia_area6(ch->ch_iot);
 
                hd6446x_intr_establish(HD64461_INTC_PCC0, IST_LEVEL, IPL_TTY,
                    hd64461pcmcia_channel0_intr, ch);
@@ -1081,14 +1103,18 @@
 }
 
 STATIC void
-fixup_sh3_pcmcia_area(bus_space_tag_t t)
+fixup_sh3_pcmcia_area6(bus_space_tag_t t)
 {
        struct hpcsh_bus_space *hbs = (void *)t;
 
+       hbs->hbs_r_1    = _sh3_pcmcia_bug_read_1;
+       hbs->hbs_rm_1   = _sh3_pcmcia_bug_read_multi_1;
+       hbs->hbs_rr_1   = _sh3_pcmcia_bug_read_region_1;
        hbs->hbs_w_1    = _sh3_pcmcia_bug_write_1;
        hbs->hbs_wm_1   = _sh3_pcmcia_bug_write_multi_1;
        hbs->hbs_wr_1   = _sh3_pcmcia_bug_write_region_1;
        hbs->hbs_sm_1   = _sh3_pcmcia_bug_set_multi_1;
+       hbs->hbs_c_1    = _sh3_pcmcia_bug_copy_region_1;
 }
 
 #ifdef HD64461PCMCIA_DEBUG