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[23.128.96.18]) by mx.google.com with ESMTP id d14si1028532ejw.459.2020.08.21.05.40.07; Fri, 21 Aug 2020 05:40:07 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=XooIBxD9; spf=pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-arm-msm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728633AbgHUMkF (ORCPT + 15 others); Fri, 21 Aug 2020 08:40:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55402 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727881AbgHUMjr (ORCPT ); Fri, 21 Aug 2020 08:39:47 -0400 Received: from mail-lj1-x242.google.com (mail-lj1-x242.google.com [IPv6:2a00:1450:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 82335C061386 for ; Fri, 21 Aug 2020 05:39:44 -0700 (PDT) Received: by mail-lj1-x242.google.com with SMTP id g6so1661005ljn.11 for ; Fri, 21 Aug 2020 05:39:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Yt/LyldY66/pFwPDGeXJ8z0VFMR5hGFFUKYdFpYipWk=; b=XooIBxD9NpfvCnmLijRKkNkTkeMMIlnFg0kpeEhmSI1UCEyX/VnmJ9wgj8KDgf/bDo l2wiTaKka9AcdCyzjCBQVMz/s1hjeiGpewkXuNPAiMMkiVGPgBGDl3b3IqXwiVV2Izyo A8KGlQ5M2Aco7pYHvWVBZf4OsbStJTX8Pa0J5jswDhjubqTyl4/HFumi9Zz69qG48YLI HtB6DcCA47U5sMGvOWg7afVGm2hvf6teBF9OdMjt/jgTbLJrfht41Dfhb+8sWqMg01h4 AXMLIsx67k4dzfD6gyhverK5NgV+fJ5MaYGApSojOQ4jsezK7r1V7WI7hbP7f+t/Bhyw hGBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Yt/LyldY66/pFwPDGeXJ8z0VFMR5hGFFUKYdFpYipWk=; b=k9+ACd3bVmXyHGg+gliJ/pc+GxBVBjTPI9Td5p6U5+Xgv+nQ4cH7ne1+XnKAODE51Q gAyT949xG2x3jfgB+klIeVIETPHf2Nk2JcqHaRYYj3zgk5xD674nDUiPyVups02nKXYK gV3WfPg2V7V9v7D9DPL4K6Zm1v0gLSQRwWIMRlMWqFTgwqLjccExGB7jt2FUXSnRvu7i YhVsuZEkQPVL9iE9YcVTgkTrTWmTwCGsWX5eoQUGC4zDObcQeLAjvZw2KKkVT8QIaA86 8T0o6Bbh8RGVbkfndPOcdjlQwwR+rV303QaOg0HtFF41H+sqfCrexr6ULVaZmgrgUpAC NQEg== X-Gm-Message-State: AOAM530XvevY4Ma1fFjES3HL0F8CSQQh3ATtsBK9xAssFAbHoaTAzfMs Y0IeHs3Rlya06HT+oRc0oUcuK57R3ApnTA== X-Received: by 2002:a2e:a58b:: with SMTP id m11mr1405008ljp.135.1598013582813; Fri, 21 Aug 2020 05:39:42 -0700 (PDT) Received: from genomnajs.ideon.se ([85.235.10.227]) by smtp.gmail.com with ESMTPSA id s4sm360782lja.124.2020.08.21.05.39.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Aug 2020 05:39:42 -0700 (PDT) From: Linus Walleij To: Russell King Cc: linux-arm-kernel@lists.infradead.org, Andy Gross , Bjorn Andersson , linux-arm-msm@vger.kernel.org, Linus Walleij Subject: [PATCH 1/3] ARM: debug: Split waituart to CTS and TXRDY Date: Fri, 21 Aug 2020 14:39:34 +0200 Message-Id: <20200821123936.153793-2-linus.walleij@linaro.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200821123936.153793-1-linus.walleij@linaro.org> References: <20200821123936.153793-1-linus.walleij@linaro.org> MIME-Version: 1.0 Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org This patch was triggered by a remark from Russell that introducing a call to the waituart (needed to fix debug prints on the Qualcomm platforms) was dangerous because in some cases this will involve waiting for a modem CTS (clear to send) signal, and debug messages would maybe not work on platforms with no modem connected to the UART port: they will just hang waiting for the modem to assert CTS and this might never happen. Looking through all UART debug drivers implementing the waituart macro I discovered that all users except two actually use this macro to check if the UART is ready for TX, let's call this TXRDY. Only two debug UART drivers actually check for CTS: - arch/arm/include/debug/8250.S - arch/arm/include/debug/tegra.S The former is very significant since the 8250 is possibly the most common UART on the planet. We have the following problem: the semantics of waituart are ambiguous making it dangerous to introduce the macro to debug code fixing debug prints for Qualcomm. To start to pry this problem apart, this patch does the following: - Convert all debug UART drivers to define two macros: - waituartcts with the clear semantic to wait for CTS to be asserted - waituarttxrdy with the clear semantic to wait for the TX capability of the UART to be ready - When doing this take care to assign the right function to each drivers macro, so they now do exactly the above. - Update the three sites in the kernel invoking the waituart macro to call waituartcts/waituarttxrdy in sequence, so that the functional impact on the kernel should be zero. After this we can start to change the code sites using this code to do the right thing. Signed-off-by: Linus Walleij --- arch/arm/boot/compressed/debug.S | 3 ++- arch/arm/include/debug/8250.S | 5 ++++- arch/arm/include/debug/asm9260.S | 5 ++++- arch/arm/include/debug/at91.S | 5 ++++- arch/arm/include/debug/bcm63xx.S | 5 ++++- arch/arm/include/debug/brcmstb.S | 5 ++++- arch/arm/include/debug/clps711x.S | 5 ++++- arch/arm/include/debug/dc21285.S | 5 ++++- arch/arm/include/debug/digicolor.S | 5 ++++- arch/arm/include/debug/efm32.S | 5 ++++- arch/arm/include/debug/icedcc.S | 15 ++++++++++++--- arch/arm/include/debug/imx.S | 5 ++++- arch/arm/include/debug/meson.S | 5 ++++- arch/arm/include/debug/msm.S | 5 ++++- arch/arm/include/debug/omap2plus.S | 5 ++++- arch/arm/include/debug/pl01x.S | 5 ++++- arch/arm/include/debug/renesas-scif.S | 5 ++++- arch/arm/include/debug/sa1100.S | 5 ++++- arch/arm/include/debug/samsung.S | 5 ++++- arch/arm/include/debug/sirf.S | 5 ++++- arch/arm/include/debug/sti.S | 5 ++++- arch/arm/include/debug/stm32.S | 5 ++++- arch/arm/include/debug/tegra.S | 5 ++++- arch/arm/include/debug/vf.S | 5 ++++- arch/arm/include/debug/vt8500.S | 5 ++++- arch/arm/include/debug/zynq.S | 5 ++++- arch/arm/kernel/debug.S | 6 ++++-- 27 files changed, 114 insertions(+), 30 deletions(-) -- 2.26.2 diff --git a/arch/arm/boot/compressed/debug.S b/arch/arm/boot/compressed/debug.S index 6bf2917a4621..97f4e74692e8 100644 --- a/arch/arm/boot/compressed/debug.S +++ b/arch/arm/boot/compressed/debug.S @@ -8,7 +8,8 @@ ENTRY(putc) addruart r1, r2, r3 - waituart r3, r1 + waituartcts r3, r1 + waituarttxrdy r3, r1 senduart r0, r1 busyuart r3, r1 mov pc, lr diff --git a/arch/arm/include/debug/8250.S b/arch/arm/include/debug/8250.S index e4a036f082c2..769246d87fff 100644 --- a/arch/arm/include/debug/8250.S +++ b/arch/arm/include/debug/8250.S @@ -45,7 +45,10 @@ bne 1002b .endm - .macro waituart,rd,rx + .macro waituarttxrdy,rd,rx + .endm + + .macro waituartcts,rd,rx #ifdef CONFIG_DEBUG_UART_8250_FLOW_CONTROL 1001: load \rd, [\rx, #UART_MSR << UART_SHIFT] tst \rd, #UART_MSR_CTS diff --git a/arch/arm/include/debug/asm9260.S b/arch/arm/include/debug/asm9260.S index 0da1eb625331..5a0ce145c44a 100644 --- a/arch/arm/include/debug/asm9260.S +++ b/arch/arm/include/debug/asm9260.S @@ -11,7 +11,10 @@ ldr \rv, = CONFIG_DEBUG_UART_VIRT .endm - .macro waituart,rd,rx + .macro waituarttxrdy,rd,rx + .endm + + .macro waituartcts,rd,rx .endm .macro senduart,rd,rx diff --git a/arch/arm/include/debug/at91.S b/arch/arm/include/debug/at91.S index 6c91cbaaa20b..17722824e2f2 100644 --- a/arch/arm/include/debug/at91.S +++ b/arch/arm/include/debug/at91.S @@ -19,12 +19,15 @@ strb \rd, [\rx, #(AT91_DBGU_THR)] @ Write to Transmitter Holding Register .endm - .macro waituart,rd,rx + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #(AT91_DBGU_SR)] @ Read Status Register tst \rd, #AT91_DBGU_TXRDY @ DBGU_TXRDY = 1 when ready to transmit beq 1001b .endm + .macro waituartcts,rd,rx + .endm + .macro busyuart,rd,rx 1001: ldr \rd, [\rx, #(AT91_DBGU_SR)] @ Read Status Register tst \rd, #AT91_DBGU_TXEMPTY @ DBGU_TXEMPTY = 1 when transmission complete diff --git a/arch/arm/include/debug/bcm63xx.S b/arch/arm/include/debug/bcm63xx.S index 06a896227396..da65abb6738d 100644 --- a/arch/arm/include/debug/bcm63xx.S +++ b/arch/arm/include/debug/bcm63xx.S @@ -17,12 +17,15 @@ strb \rd, [\rx, #UART_FIFO_REG] .endm - .macro waituart, rd, rx + .macro waituarttxrdy, rd, rx 1001: ldr \rd, [\rx, #UART_IR_REG] tst \rd, #(1 << UART_IR_TXEMPTY) beq 1001b .endm + .macro waituartcts, rd, rx + .endm + .macro busyuart, rd, rx 1002: ldr \rd, [\rx, #UART_IR_REG] tst \rd, #(1 << UART_IR_TXTRESH) diff --git a/arch/arm/include/debug/brcmstb.S b/arch/arm/include/debug/brcmstb.S index 132a20c4a676..7ffe66993029 100644 --- a/arch/arm/include/debug/brcmstb.S +++ b/arch/arm/include/debug/brcmstb.S @@ -142,7 +142,10 @@ ARM_BE8( rev \rd, \rd ) bne 1002b .endm - .macro waituart,rd,rx + .macro waituarttxrdy,rd,rx + .endm + + .macro waituartcts,rd,rx .endm /* diff --git a/arch/arm/include/debug/clps711x.S b/arch/arm/include/debug/clps711x.S index 774a67ac3877..a983d12a6515 100644 --- a/arch/arm/include/debug/clps711x.S +++ b/arch/arm/include/debug/clps711x.S @@ -20,7 +20,10 @@ ldr \rp, =CLPS711X_UART_PADDR .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx .endm .macro senduart,rd,rx diff --git a/arch/arm/include/debug/dc21285.S b/arch/arm/include/debug/dc21285.S index d7e8c71706ab..4ec0e5e31704 100644 --- a/arch/arm/include/debug/dc21285.S +++ b/arch/arm/include/debug/dc21285.S @@ -34,5 +34,8 @@ bne 1001b .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx .endm diff --git a/arch/arm/include/debug/digicolor.S b/arch/arm/include/debug/digicolor.S index 256f5f4da275..443674cad76a 100644 --- a/arch/arm/include/debug/digicolor.S +++ b/arch/arm/include/debug/digicolor.S @@ -21,7 +21,10 @@ strb \rd, [\rx, #UA0_EMI_REC] .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx .endm .macro busyuart,rd,rx diff --git a/arch/arm/include/debug/efm32.S b/arch/arm/include/debug/efm32.S index 5ed5028306f4..b0083d6e31e8 100644 --- a/arch/arm/include/debug/efm32.S +++ b/arch/arm/include/debug/efm32.S @@ -29,7 +29,10 @@ strb \rd, [\rx, #UARTn_TXDATA] .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #UARTn_STATUS] tst \rd, #UARTn_STATUS_TXBL beq 1001b diff --git a/arch/arm/include/debug/icedcc.S b/arch/arm/include/debug/icedcc.S index 74a0dd036a17..d5e65da8a687 100644 --- a/arch/arm/include/debug/icedcc.S +++ b/arch/arm/include/debug/icedcc.S @@ -23,7 +23,10 @@ beq 1001b .endm - .macro waituart, rd, rx + .macro waituartcts, rd, rx + .endm + + .macro waituarttxrdy, rd, rx mov \rd, #0x2000000 1001: subs \rd, \rd, #1 @@ -47,7 +50,10 @@ beq 1001b .endm - .macro waituart, rd, rx + .macro waituartcts, rd, rx + .endm + + .macro waituarttxrdy, rd, rx mov \rd, #0x10000000 1001: subs \rd, \rd, #1 @@ -72,7 +78,10 @@ .endm - .macro waituart, rd, rx + .macro waituartcts, rd, rx + .endm + + .macro waituarttxrdy, rd, rx mov \rd, #0x2000000 1001: subs \rd, \rd, #1 diff --git a/arch/arm/include/debug/imx.S b/arch/arm/include/debug/imx.S index 1c1b9d1da4c8..bb7b9550580c 100644 --- a/arch/arm/include/debug/imx.S +++ b/arch/arm/include/debug/imx.S @@ -35,7 +35,10 @@ str \rd, [\rx, #0x40] @ TXDATA .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx .endm .macro busyuart,rd,rx diff --git a/arch/arm/include/debug/meson.S b/arch/arm/include/debug/meson.S index 1e501a0054ae..7b60e4401225 100644 --- a/arch/arm/include/debug/meson.S +++ b/arch/arm/include/debug/meson.S @@ -25,7 +25,10 @@ beq 1002b .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #MESON_AO_UART_STATUS] tst \rd, #MESON_AO_UART_TX_FIFO_FULL bne 1001b diff --git a/arch/arm/include/debug/msm.S b/arch/arm/include/debug/msm.S index 9405b71461da..530edc74f9a3 100644 --- a/arch/arm/include/debug/msm.S +++ b/arch/arm/include/debug/msm.S @@ -17,7 +17,10 @@ ARM_BE8(rev \rd, \rd ) str \rd, [\rx, #0x70] .endm - .macro waituart, rd, rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy, rd, rx @ check for TX_EMT in UARTDM_SR ldr \rd, [\rx, #0x08] ARM_BE8(rev \rd, \rd ) diff --git a/arch/arm/include/debug/omap2plus.S b/arch/arm/include/debug/omap2plus.S index b5696a33ba0f..0680be6c79d3 100644 --- a/arch/arm/include/debug/omap2plus.S +++ b/arch/arm/include/debug/omap2plus.S @@ -75,5 +75,8 @@ omap_uart_lsr: .word 0 bne 1001b .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx .endm diff --git a/arch/arm/include/debug/pl01x.S b/arch/arm/include/debug/pl01x.S index a2a553afe7b8..0c7bfa4c10db 100644 --- a/arch/arm/include/debug/pl01x.S +++ b/arch/arm/include/debug/pl01x.S @@ -26,7 +26,10 @@ strb \rd, [\rx, #UART01x_DR] .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #UART01x_FR] ARM_BE8( rev \rd, \rd ) tst \rd, #UART01x_FR_TXFF diff --git a/arch/arm/include/debug/renesas-scif.S b/arch/arm/include/debug/renesas-scif.S index 25f06663a9a4..8e433e981bbe 100644 --- a/arch/arm/include/debug/renesas-scif.S +++ b/arch/arm/include/debug/renesas-scif.S @@ -33,7 +33,10 @@ ldr \rv, =SCIF_VIRT .endm - .macro waituart, rd, rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy, rd, rx 1001: ldrh \rd, [\rx, #FSR] tst \rd, #TDFE beq 1001b diff --git a/arch/arm/include/debug/sa1100.S b/arch/arm/include/debug/sa1100.S index 6109e6058e5b..7968ea52df3d 100644 --- a/arch/arm/include/debug/sa1100.S +++ b/arch/arm/include/debug/sa1100.S @@ -51,7 +51,10 @@ str \rd, [\rx, #UTDR] .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #UTSR1] tst \rd, #UTSR1_TNF beq 1001b diff --git a/arch/arm/include/debug/samsung.S b/arch/arm/include/debug/samsung.S index 69201d7fb48f..ab474d564a90 100644 --- a/arch/arm/include/debug/samsung.S +++ b/arch/arm/include/debug/samsung.S @@ -69,7 +69,10 @@ ARM_BE8(rev \rd, \rd) 1002: @ exit busyuart .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx ldr \rd, [\rx, # S3C2410_UFCON] ARM_BE8(rev \rd, \rd) tst \rd, #S3C2410_UFCON_FIFOMODE @ fifo enabled? diff --git a/arch/arm/include/debug/sirf.S b/arch/arm/include/debug/sirf.S index e73e4de0a015..3612c7b9cbe7 100644 --- a/arch/arm/include/debug/sirf.S +++ b/arch/arm/include/debug/sirf.S @@ -29,7 +29,10 @@ .macro busyuart,rd,rx .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #SIRF_LLUART_TXFIFO_STATUS] tst \rd, #SIRF_LLUART_TXFIFO_EMPTY beq 1001b diff --git a/arch/arm/include/debug/sti.S b/arch/arm/include/debug/sti.S index 6b42c91f217d..72d052511890 100644 --- a/arch/arm/include/debug/sti.S +++ b/arch/arm/include/debug/sti.S @@ -45,7 +45,10 @@ strb \rd, [\rx, #ASC_TX_BUF_OFF] .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #ASC_STA_OFF] tst \rd, #ASC_STA_TX_FULL bne 1001b diff --git a/arch/arm/include/debug/stm32.S b/arch/arm/include/debug/stm32.S index f3c4a37210ed..b6d9df30e37d 100644 --- a/arch/arm/include/debug/stm32.S +++ b/arch/arm/include/debug/stm32.S @@ -27,7 +27,10 @@ strb \rd, [\rx, #STM32_USART_TDR_OFF] .endm -.macro waituart,rd,rx +.macro waituartcts,rd,rx +.endm + +.macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #(STM32_USART_SR_OFF)] @ Read Status Register tst \rd, #STM32_USART_TXE @ TXE = 1 = tx empty beq 1001b diff --git a/arch/arm/include/debug/tegra.S b/arch/arm/include/debug/tegra.S index 2148d0f88591..2bca6358cdd0 100644 --- a/arch/arm/include/debug/tegra.S +++ b/arch/arm/include/debug/tegra.S @@ -178,7 +178,7 @@ 1002: .endm - .macro waituart, rd, rx + .macro waituartcts, rd, rx #ifdef FLOW_CONTROL cmp \rx, #0 beq 1002f @@ -189,6 +189,9 @@ #endif .endm + .macro waituarttxrdy,rd,rx + .endm + /* * Storage for the state maintained by the macros above. * diff --git a/arch/arm/include/debug/vf.S b/arch/arm/include/debug/vf.S index 854d9bd82770..035bcbf117ab 100644 --- a/arch/arm/include/debug/vf.S +++ b/arch/arm/include/debug/vf.S @@ -29,5 +29,8 @@ beq 1001b @ wait until transmit done .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx .endm diff --git a/arch/arm/include/debug/vt8500.S b/arch/arm/include/debug/vt8500.S index 8dc1df2d91b8..d01094fdbc8c 100644 --- a/arch/arm/include/debug/vt8500.S +++ b/arch/arm/include/debug/vt8500.S @@ -28,7 +28,10 @@ bne 1001b .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx .endm #endif diff --git a/arch/arm/include/debug/zynq.S b/arch/arm/include/debug/zynq.S index 58d77c972fd6..5d42cc35ecf3 100644 --- a/arch/arm/include/debug/zynq.S +++ b/arch/arm/include/debug/zynq.S @@ -33,7 +33,10 @@ strb \rd, [\rx, #UART_FIFO_OFFSET] @ TXDATA .endm - .macro waituart,rd,rx + .macro waituartcts,rd,rx + .endm + + .macro waituarttxrdy,rd,rx 1001: ldr \rd, [\rx, #UART_SR_OFFSET] ARM_BE8( rev \rd, \rd ) tst \rd, #UART_SR_TXEMPTY diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S index e112072b579d..e7c87522c176 100644 --- a/arch/arm/kernel/debug.S +++ b/arch/arm/kernel/debug.S @@ -89,11 +89,13 @@ ENTRY(printascii) 2: teq r1, #'\n' bne 3f mov r1, #'\r' - waituart r2, r3 + waituartcts r2, r3 + waituarttxrdy r2, r3 senduart r1, r3 busyuart r2, r3 mov r1, #'\n' -3: waituart r2, r3 +3: waituartcts r2, r3 + waituarttxrdy r2, r3 senduart r1, r3 busyuart r2, r3 b 1b From patchwork Fri Aug 21 12:39:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Walleij X-Patchwork-Id: 248118 Delivered-To: patch@linaro.org Received: by 2002:a05:6e02:522:0:0:0:0 with SMTP id h2csp310789ils; Fri, 21 Aug 2020 05:39:58 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzLA6mSnCOM8Sf+r5oGlEnP514Yy/icthPRxZINclQELkIjiPJuoLm7HW/CoPxzED22ubi1 X-Received: by 2002:a17:906:1c84:: with SMTP id g4mr2876479ejh.50.1598013598254; Fri, 21 Aug 2020 05:39:58 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1598013598; cv=none; d=google.com; s=arc-20160816; b=Z6HYmjtVAcTCuRPm1FWt0NQh1hg05GQXd9lbj1fAFdUiID7c39bcPrv35rbZUl1JeD hIcTpoxFG0XMikC/EMBDeVSDjVY8PiiEc1q1vJK5OHiiRO1DibQ9CwvpAL0bwJxR29Ta my17VYul7j3woz6KDTi1IvkcyxCv/hJDMl3t559o8yUrqamgTR7HRdIVDV1FnQItidPS v689XbMWTEI3nIHWvoj01ZPpPQr75vEQVwVmE1cC24KFMX22KXkmXqPN/BRRA77+fiKk gOANANu6poWnCczhTTfyyUGgwbnxHTTbTQtYNLYuy2BA2ybEI0vi9fFfs080XaPiLTmC jgAg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=9fiy2iATlfEw3mL+m1CzukWRNox6olxQRmmk+sPk6mE=; b=I4BGRiDTv0j4PXrpXOI3dwMKm1B4I3yi7kSLzbuJyFBojEFP/L0UeuyqNP/NVebzIU Dcy243v1xhds7F6k5axkSua/nE7xANEryNS+Bb9k54BLsi3VfzqdlPyQ20D4BvnFhg9W kear1YcnGtEdxb0rOHUwg3r3tF3vLCHIGHlaWbsviayhhDND6WTdBilbOGrxey3nr9jN JP3O82ycICZOTX0svbOz374KPxG51xTWAHLCeiJin/W1dJXwXD/q5J/0QeD+lWziX0e/ vPZrA9Qh7u7ZeimwZ83LrJT1WoZCo0ODm9TP1wQoF8SXlwaMxrJYCjuGf5xsoQlWTEAE AAEw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=aQMumDMP; spf=pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-arm-msm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. 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If the debug UART supports waiting for CTS to be asserted, then this code can be activated for terminals that need it. We keep the defaults for EBSA110, Footbridge, Gemini and RPC so that this still works as expected for these older platforms: they assume that flow control shall be enabled for debug prints. I switch the location of the check for ifdef CONFIG_DEBUG_UART_FLOW_CONTROL from the actual debug UART drivers: the code would get compiled-out for 8250 and Tegra unless their custom config (or passing -DFLOW_CONTROL in the Tegra case) was not set. Instead this is conditional at the three places where we print debug messages. The idea is that debug UARTs can be implemented without this ifdef boilerplate so they look cleaner, alas the ifdef has to be somewhere. Signed-off-by: Linus Walleij --- Spreading out the ifdef CONFIG_DEBUG_UART_FLOW_CONTROL is a bit of a taste choice, if preferred I can keep it in each UART driver as well. If many UART drivers implement this it is likely better like this IMO but I can do it either way. --- arch/arm/Kconfig.debug | 16 +++++++++++----- arch/arm/boot/compressed/debug.S | 2 ++ arch/arm/include/debug/8250.S | 2 -- arch/arm/include/debug/tegra.S | 2 -- arch/arm/kernel/debug.S | 7 ++++++- 5 files changed, 19 insertions(+), 10 deletions(-) -- 2.26.2 diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug index 80000a66a4e3..87912e5c2256 100644 --- a/arch/arm/Kconfig.debug +++ b/arch/arm/Kconfig.debug @@ -1546,6 +1546,17 @@ config DEBUG_SIRFSOC_UART bool depends on ARCH_SIRF +config DEBUG_UART_FLOW_CONTROL + bool "Enable flow control (CTS) for the debug UART" + depends on DEBUG_LL + default y if ARCH_EBSA110 || DEBUG_FOOTBRIDGE_COM1 || DEBUG_GEMINI || ARCH_RPC + help + Some UART ports are connected to terminals that will use modem + control signals to indicate whether they are ready to receive text. + In practice this means that the terminal is asserting the special + control signal CTS (Clear To Send). If your debug UART supports + this and your debug terminal will require it, enable this option. + config DEBUG_LL_INCLUDE string default "debug/sa1100.S" if DEBUG_SA1100 @@ -1893,11 +1904,6 @@ config DEBUG_UART_8250_PALMCHIP except for having a different register layout. Say Y here if the debug UART is of this type. -config DEBUG_UART_8250_FLOW_CONTROL - bool "Enable flow control for 8250 UART" - depends on DEBUG_LL_UART_8250 || DEBUG_UART_8250 - default y if ARCH_EBSA110 || DEBUG_FOOTBRIDGE_COM1 || DEBUG_GEMINI || ARCH_RPC - config DEBUG_UNCOMPRESS bool "Enable decompressor debugging via DEBUG_LL output" depends on ARCH_MULTIPLATFORM || PLAT_SAMSUNG || ARM_SINGLE_ARMV7M diff --git a/arch/arm/boot/compressed/debug.S b/arch/arm/boot/compressed/debug.S index 97f4e74692e8..fac40a717fcf 100644 --- a/arch/arm/boot/compressed/debug.S +++ b/arch/arm/boot/compressed/debug.S @@ -8,7 +8,9 @@ ENTRY(putc) addruart r1, r2, r3 +#ifdef CONFIG_DEBUG_UART_FLOW_CONTROL waituartcts r3, r1 +#endif waituarttxrdy r3, r1 senduart r0, r1 busyuart r3, r1 diff --git a/arch/arm/include/debug/8250.S b/arch/arm/include/debug/8250.S index 769246d87fff..e3692a37cede 100644 --- a/arch/arm/include/debug/8250.S +++ b/arch/arm/include/debug/8250.S @@ -49,9 +49,7 @@ .endm .macro waituartcts,rd,rx -#ifdef CONFIG_DEBUG_UART_8250_FLOW_CONTROL 1001: load \rd, [\rx, #UART_MSR << UART_SHIFT] tst \rd, #UART_MSR_CTS beq 1001b -#endif .endm diff --git a/arch/arm/include/debug/tegra.S b/arch/arm/include/debug/tegra.S index 2bca6358cdd0..98daa7f48314 100644 --- a/arch/arm/include/debug/tegra.S +++ b/arch/arm/include/debug/tegra.S @@ -179,14 +179,12 @@ .endm .macro waituartcts, rd, rx -#ifdef FLOW_CONTROL cmp \rx, #0 beq 1002f 1001: ldrb \rd, [\rx, #UART_MSR << UART_SHIFT] tst \rd, #UART_MSR_CTS beq 1001b 1002: -#endif .endm .macro waituarttxrdy,rd,rx diff --git a/arch/arm/kernel/debug.S b/arch/arm/kernel/debug.S index e7c87522c176..d92f44bdf438 100644 --- a/arch/arm/kernel/debug.S +++ b/arch/arm/kernel/debug.S @@ -89,12 +89,17 @@ ENTRY(printascii) 2: teq r1, #'\n' bne 3f mov r1, #'\r' +#ifdef CONFIG_DEBUG_UART_FLOW_CONTROL waituartcts r2, r3 +#endif waituarttxrdy r2, r3 senduart r1, r3 busyuart r2, r3 mov r1, #'\n' -3: waituartcts r2, r3 +3: +#ifdef CONFIG_DEBUG_UART_FLOW_CONTROL + waituartcts r2, r3 +#endif waituarttxrdy r2, r3 senduart r1, r3 busyuart r2, r3 From patchwork Fri Aug 21 12:39:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Linus Walleij X-Patchwork-Id: 248120 Delivered-To: patch@linaro.org Received: by 2002:a05:6e02:522:0:0:0:0 with SMTP id h2csp310935ils; Fri, 21 Aug 2020 05:40:10 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxhH7hi4NJa/xnEH3JqrXg3QWRR61OmJhaWYgABGfWzX22M/MHbZOSjuo1RC5iWKdfMaDU9 X-Received: by 2002:a50:9996:: with SMTP id m22mr2025856edb.241.1598013610629; Fri, 21 Aug 2020 05:40:10 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1598013610; cv=none; d=google.com; s=arc-20160816; b=YhU/fIV+N8Cepxoog+0pvmsiFOrXnvI3D/lSTnf8QjSxqC01Fbg6w8hurBFGTQJJ7P XkGcF5JdeOA/lyK8ZUbu3LT0Z7evG0kLUORygS9AxaEdFyO53Hqc3MtazdfPzeaG0KR0 cEj1/lz4pXKOAM7+SIijn3i5NlEdJTVicO89rKHFYWt7sml1EAaZ8euYrnv6cGYE7FfD KcIf3jXEUYdbrJpiuG/2P7XaMqlAlcDgToJcYo3dPSyVL2clJt31KmIcxM1gBMyCFsyZ QEq5srCWvGOi8Mm9Z+ux++4j1gSU5CtsyWRS02dBUarq2Bu1Z8r7LJVG7CTPpS1dv4Fa ISOA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=BgadfB5krB76vfFemnEl7mqgct62PL+apkSnkJxl7rU=; b=GGKQ48A3DRIv7sFTj5+72Npvv2wHMRbOFC/jufE76OPTry7ZGRMVXTkWT3ps/gpU65 jHyZf9c2yTk4Sy64ocCGA97sJ5LdZ66Mki0ARYtYFzSdnaRT0pL57/vy4LKKisvlibgO LbT/r9TC60yannHHNhAmjYqszIdr1zVIgixsMatomD40GyUCKz+Afm1dSIDvrYw/T/b2 yKkntvPHWENS0YFfbk+Nz1seT5GMzbIOI3yDmqEbuLVzUsxVVPty9z3bJfAtVIXaHACq MWRYEffy5UwVyIK66FSWKQ+PoWFVeaFgXOnl6ICpYis/wTyLq1Vj1eseKkeKkrFVu2Ep GLNw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=ma7MklMj; spf=pass (google.com: domain of linux-arm-msm-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-arm-msm-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. 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Pass an extra temporary variable to writeb and make it call waituarttxrdy and busyuart just like the other decomression messages. Optionally it will also call waituartcts if and only if CONFIG_DEBUG_UART_FLOW_CONTROL is selected. After this the decompression debug messages work fine on Qualcomm platforms if you compile head.S with -DDEBUG. Cc: Nicolas Pitre Cc: Fabrizio Castro Cc: Ard Biesheuvel Signed-off-by: Linus Walleij --- arch/arm/boot/compressed/head.S | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) -- 2.26.2 diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index ba121eea9468..5c9c6fe590cb 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -28,19 +28,19 @@ #if defined(CONFIG_CPU_V6) || defined(CONFIG_CPU_V6K) || defined(CONFIG_CPU_V7) .macro loadsp, rb, tmp1, tmp2 .endm - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp mcr p14, 0, \ch, c0, c5, 0 .endm #elif defined(CONFIG_CPU_XSCALE) .macro loadsp, rb, tmp1, tmp2 .endm - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp mcr p14, 0, \ch, c8, c0, 0 .endm #else .macro loadsp, rb, tmp1, tmp2 .endm - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp mcr p14, 0, \ch, c1, c0, 0 .endm #endif @@ -49,8 +49,13 @@ #include CONFIG_DEBUG_LL_INCLUDE - .macro writeb, ch, rb + .macro writeb, ch, rb, tmp +#ifdef CONFIG_DEBUG_UART_FLOW_CONTROL + waituartcts \tmp, \rb +#endif + waituarttxrdy \tmp, \rb senduart \ch, \rb + busyuart \tmp, \rb .endm #if defined(CONFIG_ARCH_SA1100) @@ -1326,7 +1331,7 @@ puts: loadsp r3, r2, r1 1: ldrb r2, [r0], #1 teq r2, #0 moveq pc, lr -2: writeb r2, r3 +2: writeb r2, r3, r1 mov r1, #0x00020000 3: subs r1, r1, #1 bne 3b