From d35903b0e772c0cdcd3f685dbee81ffbd110a24a Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Fri, 17 May 2019 06:50:54 +0200
Subject: [PATCH 27/53] pflash_cfi01: Log use of flawed "write to buffer"
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RH-Author: Markus Armbruster <armbru@redhat.com>
Message-id: <20190517065120.12028-6-armbru@redhat.com>
Patchwork-id: 87990
O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH v3 05/31] pflash_cfi01: Log use of flawed "write to buffer"
Bugzilla: 1624009
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

Our implementation of "write to buffer" (command 0xE8) is flawed.
LOG_UNIMP its use, and add some FIXME comments.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20190308094610.21210-4-armbru@redhat.com>
(cherry picked from commit 4dbda935e054600667f9e57095fa97e2ce5936f9)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/block/pflash_cfi01.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
index c565db1..3a6bd10 100644
--- a/hw/block/pflash_cfi01.c
+++ b/hw/block/pflash_cfi01.c
@@ -515,6 +515,10 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
             break;
         case 0xe8: /* Write to buffer */
             DPRINTF("%s: Write to buffer\n", __func__);
+            /* FIXME should save @offset, @width for case 1+ */
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: Write to buffer emulation is flawed\n",
+                          __func__);
             pfl->status |= 0x80; /* Ready! */
             break;
         case 0xf0: /* Probe for AMD flash */
@@ -558,6 +562,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
             /* Mask writeblock size based on device width, or bank width if
              * device width not specified.
              */
+            /* FIXME check @offset, @width */
             if (pfl->device_width) {
                 value = extract32(value, 0, pfl->device_width * 8);
             } else {
@@ -595,7 +600,13 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
     case 2:
         switch (pfl->cmd) {
         case 0xe8: /* Block write */
+            /* FIXME check @offset, @width */
             if (!pfl->ro) {
+                /*
+                 * FIXME writing straight to memory is *wrong*.  We
+                 * should write to a buffer, and flush it to memory
+                 * only on confirm command (see below).
+                 */
                 pflash_data_write(pfl, offset, value, width, be);
             } else {
                 pfl->status |= 0x10; /* Programming error */
@@ -611,6 +622,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
                 pfl->wcycle++;
                 if (!pfl->ro) {
                     /* Flush the entire write buffer onto backing storage.  */
+                    /* FIXME premature! */
                     pflash_update(pfl, offset & mask, pfl->writeblock_size);
                 } else {
                     pfl->status |= 0x10; /* Programming error */
@@ -627,6 +639,7 @@ static void pflash_write(PFlashCFI01 *pfl, hwaddr offset,
         switch (pfl->cmd) {
         case 0xe8: /* Block write */
             if (cmd == 0xd0) {
+                /* FIXME this is where we should write out the buffer */
                 pfl->wcycle = 0;
                 pfl->status |= 0x80;
             } else {
-- 
1.8.3.1