Hi Simon,
On Wed, Sep 20, 2023 at 10:59 AM Simon Glass sjg@chromium.org wrote:
Hi Bin,
On Tue, 19 Sept 2023 at 02:47, Bin Meng bmeng.cn@gmail.com wrote:
Hi Simon,
On Mon, Sep 11, 2023 at 3:13 AM Simon Glass sjg@chromium.org wrote:
This driver is not actually built since a Kconfig was never created for it.
Add a Kconfig (which is already implied by COREBOOT) and update the implementation to avoid using unnecessary memory. Drop the #ifdef at the top since we can rely on Kconfig to get that right.
To enable it (in addition to serial and video), use:
setenv stdout serial,vidconsole,cbmem
Signed-off-by: Simon Glass sjg@chromium.org
Changes in v4:
- Add some comments to help understand the overflow mechanism
Changes in v2:
- Update to support the new overflow mechanism
drivers/misc/Kconfig | 8 +++++++ drivers/misc/cbmem_console.c | 43 ++++++++++++++++++++++-------------- 2 files changed, 34 insertions(+), 17 deletions(-)
diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index a6e3f62ecb09..c930e4a361bf 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -122,6 +122,14 @@ config VEXPRESS_CONFIG configuration bus on the Arm Versatile Express boards via a sysreg driver.
+config CBMEM_CONSOLE
bool "Write console output to coreboot cbmem"depends on X86helpEnables console output to the cbmem console, which is a memoryregion set up by coreboot to hold a record of all console output.Enable this only if booting from coreboot.config CMD_CROS_EC bool "Enable crosec command" depends on CROS_EC diff --git a/drivers/misc/cbmem_console.c b/drivers/misc/cbmem_console.c index 8bbe33d414da..3cbe9fb1a46a 100644 --- a/drivers/misc/cbmem_console.c +++ b/drivers/misc/cbmem_console.c @@ -5,27 +5,37 @@
#include <common.h> #include <console.h> -#ifndef CONFIG_SYS_COREBOOT -#error This driver requires coreboot -#endif
#include <asm/cb_sysinfo.h>
-struct cbmem_console {
u32 buffer_size;u32 buffer_cursor;u8 buffer_body[0];-} __attribute__ ((__packed__));
-static struct cbmem_console *cbmem_console_p;
void cbmemc_putc(struct stdio_dev *dev, char data) {
int cursor;
const struct sysinfo_t *sysinfo = cb_get_sysinfo();struct cbmem_console *cons;uint pos, flags;if (!sysinfo)return;cons = sysinfo->cbmem_cons;if (!cons)return;pos = cons->cursor & CBMC_CURSOR_MASK;/* preserve the overflow flag if present */flags = cons->cursor & ~CBMC_CURSOR_MASK;cons->body[pos++] = data;/** Deal with overflow - the flag may be cleared by another program which* reads the buffer out, e.g. Linux*/U-Boot is not memory resident, so this does not sound like a correct overflow mechanism to me.
I am not sure what you mean. This logic is used in coreboot and some payloads, so I want to do the same in U-Boot. It basically let's U-Boot handle an overflow properly by setting the overflow flag. A later program (e.g. Linux) can then tell that that an overflow occurred.
Okay, I modified the comment to
/* * Deal with overflow - the flag may be cleared by another program which * reads the buffer out later, e.g. Linux */
which makes more sense.
applied to u-boot-x86/next, thanks!
Regards, Bin