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[31.208.27.151]) by smtp.gmail.com with ESMTPSA id g2-20020a2eb0c2000000b002555d6ca497sm1604724ljl.115.2022.06.20.04.22.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Jun 2022 04:22:25 -0700 (PDT) Date: Mon, 20 Jun 2022 13:22:23 +0200 From: Francisco Iglesias To: Dan Zhang Cc: qemu-devel@nongnu.org, clg@kaod.org, alistair@alistair23.me, andrew@aj.id.au, hreitz@redhat.com, irischenlj@fb.com, irischenlj@gmail.com, joel@jms.id.au, kwolf@redhat.com, lvivier@redhat.com, patrick@stwcx.xyz, pbonzini@redhat.com, pdel@fb.com, peter.maydell@linaro.org, qemu-arm@nongnu.org, qemu-block@nongnu.org, thuth@redhat.com Subject: Re: [PATCH] hw:m25p80: Add STATE_STANDBY command state Message-ID: <20220620112220.GA10802@fralle-msi> References: <20220614200205.2945065-1-dz4list@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220614200205.2945065-1-dz4list@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Received-SPF: pass client-ip=2a00:1450:4864:20::232; envelope-from=frasse.iglesias@gmail.com; helo=mail-lj1-x232.google.com X-Spam_score_int: -1020 X-Spam_score: -102.1 X-Spam_bar: --------------------------------------------------- X-Spam_report: (-102.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01, USER_IN_WELCOMELIST=-0.01, USER_IN_WHITELIST=-100 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Dan, On [2022 Jun 14] Tue 13:02:05, Dan Zhang wrote: > HW normally will switch it to stand by mode when receive incorrect > command. > i.e. Macronix MX66L1G45G data sheet section 8 DEVICE OPERATION described > ``` > 2. When an incorrect command is written to this device, it enters > standby mode and stays in standby mode until the next CS# falling edge. > In standby mode, This device's SO pin should be High-Z. > ``` > Add STATE_STANDBY CMDState and let the device ignore all input and keep > SO as HIZ (output 1) > > Signed-off-by: Dan Zhang > --- > A usage of this new state can be aborting in HPM checking > or unknown command code received. > > hw/block/m25p80.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c > index b6bd430a99..9f89773b11 100644 > --- a/hw/block/m25p80.c > +++ b/hw/block/m25p80.c > @@ -423,6 +423,7 @@ typedef enum { > STATE_COLLECTING_DATA, > STATE_COLLECTING_VAR_LEN_DATA, > STATE_READING_DATA, > + STATE_STANDBY, Should we enter the state also? (Otherwise we will be adding code that is unused). > } CMDState; > > typedef enum { > @@ -1472,6 +1473,9 @@ static uint32_t m25p80_transfer8(SSIPeripheral *ss, uint32_t tx) > s->cur_addr, (uint8_t)tx); > > switch (s->state) { > + case STATE_STANDBY: > + r = 0xFFFFFFFF; /* StandBy state SO shall be HiZ */ 0xFF should be enough here (since we are dealing with 8 bits, e.g. m25p80_transfer8). More safe is probably to return 0 though and see this as if a pulldown was connected to the line instead (this because r has been default to 0 and was the most likely return value before in this situation). If you would agree we can remove above line. Thanks, Best regards, Francisco Iglesias > + break; > > case STATE_PAGE_PROGRAM: > trace_m25p80_page_program(s, s->cur_addr, (uint8_t)tx); > -- > 2.34.3 >