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2006-10-05IRQ: Maintain regs pointer globally rather than passing to IRQ handlersDavid Howells
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead of passing regs around manually through all ~1800 interrupt handlers in the Linux kernel. The regs pointer is used in few places, but it potentially costs both stack space and code to pass it around. On the FRV arch, removing the regs parameter from all the genirq function results in a 20% speed up of the IRQ exit path (ie: from leaving timer_interrupt() to leaving do_IRQ()). Where appropriate, an arch may override the generic storage facility and do something different with the variable. On FRV, for instance, the address is maintained in GR28 at all times inside the kernel as part of general exception handling. Having looked over the code, it appears that the parameter may be handed down through up to twenty or so layers of functions. Consider a USB character device attached to a USB hub, attached to a USB controller that posts its interrupts through a cascaded auxiliary interrupt controller. A character device driver may want to pass regs to the sysrq handler through the input layer which adds another few layers of parameter passing. I've build this code with allyesconfig for x86_64 and i386. I've runtested the main part of the code on FRV and i386, though I can't test most of the drivers. I've also done partial conversion for powerpc and MIPS - these at least compile with minimal configurations. This will affect all archs. Mostly the changes should be relatively easy. Take do_IRQ(), store the regs pointer at the beginning, saving the old one: struct pt_regs *old_regs = set_irq_regs(regs); And put the old one back at the end: set_irq_regs(old_regs); Don't pass regs through to generic_handle_irq() or __do_IRQ(). In timer_interrupt(), this sort of change will be necessary: - update_process_times(user_mode(regs)); - profile_tick(CPU_PROFILING, regs); + update_process_times(user_mode(get_irq_regs())); + profile_tick(CPU_PROFILING); I'd like to move update_process_times()'s use of get_irq_regs() into itself, except that i386, alone of the archs, uses something other than user_mode(). Some notes on the interrupt handling in the drivers: (*) input_dev() is now gone entirely. The regs pointer is no longer stored in the input_dev struct. (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does something different depending on whether it's been supplied with a regs pointer or not. (*) Various IRQ handler function pointers have been moved to type irq_handler_t. Signed-Off-By: David Howells <dhowells@redhat.com> (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-04[PATCH] atmel_serial: Fix roundoff error in atmel_console_get_optionsHaavard Skinnemoen
The atmel_console_get_options() function initializes the baud, parity and bits settings from the actual hardware setup, in case it has been initialized by a e.g. boot loader. The baud rate, however, is not necessarily exactly equal to one of the standard baud rates (115200, etc.) This means that the baud rate calculated by this function may be slightly higher or slightly lower than one of the standard baud rates. If the baud rate is slightly lower than the target, this causes problems when uart_set_option() tries to match the detected baud rate against the standard baud rate, as it will always select a baud rate that is lower or equal to the target rate. For example if the detected baud rate is slightly lower than 115200, usart_set_options() will select 57600. This patch fixes the problem by subtracting 1 from the value in BRGR when calculating the baud rate. The detected baud rate will thus always be higher than the nearest standard baud rate, and uart_set_options() will end up doing the right thing. Tested on ATSTK1000 and AT91RM9200-EK boards. Both are broken without this patch. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] atmel_serial: Support AVR32Haavard Skinnemoen
Make CONFIG_SERIAL_ATMEL selectable on AVR32 and #ifdef out some ARM- specific code in the driver. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] atmel_serial: Pass fixed register mappings through platform_dataHaavard Skinnemoen
In order to initialize the serial console early, the atmel_serial driver had to do a hack where it compared the physical address of the port with an address known to be permanently mapped, and used it as a virtual address. This got around the limitation that ioremap() isn't always available when the console is being initalized. This patch removes that hack and replaces it with a new "regs" field in struct atmel_uart_data that the board-specific code can initialize to a fixed virtual mapping for platform devices where this is possible. It also initializes the DBGU's regs field with the address the driver used to check against. On AVR32, the "regs" field is initialized from the physical base address when this it can be accessed through a permanently 1:1 mapped segment, i.e. the P4 segment. If regs is NULL, the console initialization is delayed until the "real" driver is up and running and ioremap() can be used. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] atmel_serial: Rename at91_register_uart_fnsHaavard Skinnemoen
Rename at91_register_uart_fns and associated structs and variables to make it consistent with the atmel_ prefix used by the rest of the driver. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] serial: Rename PORT_AT91 -> PORT_ATMELHaavard Skinnemoen
The at91_serial driver can be used with both AT32 and AT91 devices from Atmel and has therefore been renamed atmel_serial. The only thing left is to rename PORT_AT91 PORT_ATMEL. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] at91_serial -> atmel_serial: Internal namesHaavard Skinnemoen
Prefix all internal functions and variables with atmel_ instead of at91_. The at91_register_uart_fns() stuff is left as is since I can't find any actual users of it. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] at91_serial -> atmel_serial: Public definitionsHaavard Skinnemoen
Rename the following public definitions: * AT91_NR_UART -> ATMEL_MAX_UART * struct at91_uart_data -> struct atmel_uart_data * at91_default_console_device -> atmel_default_console_device Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] at91_serial -> atmel_serial: Platform device nameHaavard Skinnemoen
Rename the "at91_usart" platform driver "atmel_usart" and update platform devices accordingly. Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] at91_serial -> atmel_serial: Kconfig symbolsHaavard Skinnemoen
Rename the following Kconfig symbols: * CONFIG_SERIAL_AT91 -> CONFIG_SERIAL_ATMEL * CONFIG_SERIAL_AT91_CONSOLE -> CONFIG_SERIAL_ATMEL_CONSOLE * CONFIG_SERIAL_AT91_TTYAT -> CONFIG_SERIAL_ATMEL_TTYAT Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-04[PATCH] at91_serial -> atmel_serial: at91_serial.cHaavard Skinnemoen
Rename at91_serial.c atmel_serial.c Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Acked-by: Andrew Victor <andrew@sanpeople.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>