From 2c50a570e9dc649c182268e779dffe0712e98a6a Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Thu, 27 Aug 2020 23:25:37 +0100 Subject: [PATCH] ARM: 9004/1: debug: Split waituart to CTS and TXRDY 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 Signed-off-by: Russell King --- 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(-) diff --git a/arch/arm/boot/compressed/debug.S b/arch/arm/boot/compressed/debug.S index 6bf2917a46214..97f4e74692e89 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 e4a036f082c29..769246d87fffb 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 0da1eb6253318..5a0ce145c44ab 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 6c91cbaaa20be..17722824e2f22 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 06a8962273960..da65abb6738db 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 132a20c4a6769..7ffe66993029b 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 774a67ac3877d..a983d12a65159 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 d7e8c71706abd..4ec0e5e317048 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 256f5f4da2759..443674cad76a8 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 5ed5028306f4a..b0083d6e31e80 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 74a0dd036a175..d5e65da8a6874 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 1c1b9d1da4c8f..bb7b9550580c4 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 1e501a0054aea..7b60e4401225e 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 9405b71461daf..530edc74f9a3b 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 b5696a33ba0f5..0680be6c79d35 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 a2a553afe7b89..0c7bfa4c10dbf 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 25f06663a9a4e..8e433e981bbe8 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 6109e6058e5b3..7968ea52df3d5 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 69201d7fb48f6..ab474d564a909 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 e73e4de0a0153..3612c7b9cbe71 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 6b42c91f217d4..72d0525118908 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 f3c4a37210ed5..b6d9df30e37d2 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 2148d0f885919..2bca6358cdd06 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 854d9bd827701..035bcbf117ab3 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 8dc1df2d91b85..d01094fdbc8c8 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 58d77c972fd68..5d42cc35ecf3d 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 e112072b579d4..e7c87522c1766 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 -- 2.30.2