Skip to content

Commit

Permalink
ARM: tegra: decouple uncompress.h and debug-macro.S
Browse files Browse the repository at this point in the history 
Prior to this change, Tegra's debug-macro.S relied on uncompress.h having
determined which UART to use, and whether it was safe to use the UART
(i.e. is it not in reset, and is clocked). This determination was
communicated from uncompress.h to debug-macro.S using a few bytes of
Tegra's IRAM (an on-SoC RAM). This had the disadvantage that uncompress.h
was a required part of the kernel boot process; booting a non-compressed
kernel would not allow earlyprintk to operate.

This change duplicates the UART selection and validation logic into
debug-macro.S so that the reliance on uncompress.h is removed.

This also helps out with single-zImage work, since there is currently no
support for using any uncompress.h with single-zImage.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
  • Loading branch information
Stephen Warren committed Nov 16, 2012
1 parent adc1831 commit 1a6d3da
Show file tree
Hide file tree
Showing 4 changed files with 134 additions and 43 deletions.
4 changes: 3 additions & 1 deletion arch/arm/mach-tegra/common.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,13 +44,15 @@
* kernel is loaded. The data is declared here rather than debug-macro.S so
* that multiple inclusions of debug-macro.S point at the same data.
*/
u32 tegra_uart_config[3] = {
u32 tegra_uart_config[4] = {
/* Debug UART initialization required */
1,
/* Debug UART physical address */
0,
/* Debug UART virtual address */
0,
/* Scratch space for debug macro */
0,
};

#ifdef CONFIG_OF
Expand Down
151 changes: 131 additions & 20 deletions arch/arm/mach-tegra/include/mach/debug-macro.S
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,42 @@
#include <linux/serial_reg.h>

#include "../../iomap.h"
#include "../../irammap.h"

#define UART_SHIFT 2

#define TEGRA_CLK_RST_DEVICES_L (TEGRA_CLK_RESET_BASE + 0x04)
#define TEGRA_CLK_RST_DEVICES_H (TEGRA_CLK_RESET_BASE + 0x08)
#define TEGRA_CLK_RST_DEVICES_U (TEGRA_CLK_RESET_BASE + 0x0c)
#define TEGRA_CLK_OUT_ENB_L (TEGRA_CLK_RESET_BASE + 0x10)
#define TEGRA_CLK_OUT_ENB_H (TEGRA_CLK_RESET_BASE + 0x14)
#define TEGRA_CLK_OUT_ENB_U (TEGRA_CLK_RESET_BASE + 0x18)
#define TEGRA_PMC_SCRATCH20 (TEGRA_PMC_BASE + 0xa0)
#define TEGRA_APB_MISC_GP_HIDREV (TEGRA_APB_MISC_BASE + 0x804)

#define checkuart(rp, rv, lhu, bit, uart) \
/* Load address of CLK_RST register */ \
movw rp, #TEGRA_CLK_RST_DEVICES_##lhu & 0xffff ; \
movt rp, #TEGRA_CLK_RST_DEVICES_##lhu >> 16 ; \
/* Load value from CLK_RST register */ \
ldr rp, [rp, #0] ; \
/* Test UART's reset bit */ \
tst rp, #(1 << bit) ; \
/* If set, can't use UART; jump to save no UART */ \
bne 90f ; \
/* Load address of CLK_OUT_ENB register */ \
movw rp, #TEGRA_CLK_OUT_ENB_##lhu & 0xffff ; \
movt rp, #TEGRA_CLK_OUT_ENB_##lhu >> 16 ; \
/* Load value from CLK_OUT_ENB register */ \
ldr rp, [rp, #0] ; \
/* Test UART's clock enable bit */ \
tst rp, #(1 << bit) ; \
/* If clear, can't use UART; jump to save no UART */ \
beq 90f ; \
/* Passed all tests, load address of UART registers */ \
movw rp, #TEGRA_UART##uart##_BASE & 0xffff ; \
movt rp, #TEGRA_UART##uart##_BASE >> 16 ; \
/* Jump to save UART address */ \
b 91f

.macro addruart, rp, rv, tmp
adr \rp, 99f @ actual addr of 99f
Expand All @@ -36,50 +71,126 @@
ldr \rp, [\rp, #4] @ linked tegra_uart_config
sub \tmp, \rp, \rv @ actual tegra_uart_config
ldr \rp, [\tmp] @ Load tegra_uart_config
cmp \rp, #1 @ needs intitialization?
cmp \rp, #1 @ needs initialization?
bne 100f @ no; go load the addresses
mov \rv, #0 @ yes; record init is done
str \rv, [\tmp]
mov \rp, #TEGRA_IRAM_BASE @ See if cookie is in IRAM
ldr \rv, [\rp, #TEGRA_IRAM_DEBUG_UART_OFFSET]
movw \rp, #TEGRA_IRAM_DEBUG_UART_COOKIE & 0xffff
movt \rp, #TEGRA_IRAM_DEBUG_UART_COOKIE >> 16
cmp \rv, \rp @ Cookie present?
bne 100f @ No, use default UART
mov \rp, #TEGRA_IRAM_BASE @ Load UART address from IRAM
ldr \rv, [\rp, #TEGRA_IRAM_DEBUG_UART_OFFSET + 4]
str \rv, [\tmp, #4] @ Store in tegra_uart_phys
sub \rv, \rv, #IO_APB_PHYS @ Calculate virt address

#ifdef CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA
/* Check ODMDATA */
10: movw \rp, #TEGRA_PMC_SCRATCH20 & 0xffff
movt \rp, #TEGRA_PMC_SCRATCH20 >> 16
ldr \rp, [\rp, #0] @ Load PMC_SCRATCH20
ubfx \rv, \rp, #18, #2 @ 19:18 are console type
cmp \rv, #2 @ 2 and 3 mean DCC, UART
beq 11f @ some boards swap the meaning
cmp \rv, #3 @ so accept either
bne 90f
11: ubfx \rv, \rp, #15, #3 @ 17:15 are UART ID
cmp \rv, #0 @ UART 0?
beq 20f
cmp \rv, #1 @ UART 1?
beq 21f
cmp \rv, #2 @ UART 2?
beq 22f
cmp \rv, #3 @ UART 3?
beq 23f
cmp \rv, #4 @ UART 4?
beq 24f
b 90f @ invalid
#endif

#if defined(CONFIG_TEGRA_DEBUG_UARTA) || \
defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
/* Check UART A validity */
20: checkuart(\rp, \rv, L, 6, A)
#endif

#if defined(CONFIG_TEGRA_DEBUG_UARTB) || \
defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
/* Check UART B validity */
21: checkuart(\rp, \rv, L, 7, B)
#endif

#if defined(CONFIG_TEGRA_DEBUG_UARTC) || \
defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
/* Check UART C validity */
22: checkuart(\rp, \rv, H, 23, C)
#endif

#if defined(CONFIG_TEGRA_DEBUG_UARTD) || \
defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
/* Check UART D validity */
23: checkuart(\rp, \rv, U, 1, D)
#endif

#if defined(CONFIG_TEGRA_DEBUG_UARTE) || \
defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
/* Check UART E validity */
24:
checkuart(\rp, \rv, U, 2, E)
#endif

/* No valid UART found */
90: mov \rp, #0
/* fall through */

/* Record whichever UART we chose */
91: str \rp, [\tmp, #4] @ Store in tegra_uart_phys
cmp \rp, #0 @ Valid UART address?
bne 92f @ Yes, go process it
str \rp, [\tmp, #8] @ Store 0 in tegra_uart_phys
b 100f @ Done
92: sub \rv, \rp, #IO_APB_PHYS @ Calculate virt address
add \rv, \rv, #IO_APB_VIRT
str \rv, [\tmp, #8] @ Store in tegra_uart_virt
movw \rv, #TEGRA_APB_MISC_GP_HIDREV & 0xffff
movt \rv, #TEGRA_APB_MISC_GP_HIDREV >> 16
ldr \rv, [\rv, #0] @ Load HIDREV
ubfx \rv, \rv, #8, #8 @ 15:8 are SoC version
cmp \rv, #0x20 @ Tegra20?
moveq \rv, #0x75 @ Tegra20 divisor
movne \rv, #0xdd @ Tegra30 divisor
str \rv, [\tmp, #12] @ Save divisor to scratch
/* uart[UART_LCR] = UART_LCR_WLEN8 | UART_LCR_DLAB; */
mov \rv, #UART_LCR_WLEN8 | UART_LCR_DLAB
str \rv, [\rp, #UART_LCR << UART_SHIFT]
/* uart[UART_DLL] = div & 0xff; */
ldr \rv, [\tmp, #12]
and \rv, \rv, #0xff
str \rv, [\rp, #UART_DLL << UART_SHIFT]
/* uart[UART_DLM] = div >> 8; */
ldr \rv, [\tmp, #12]
lsr \rv, \rv, #8
str \rv, [\rp, #UART_DLM << UART_SHIFT]
/* uart[UART_LCR] = UART_LCR_WLEN8; */
mov \rv, #UART_LCR_WLEN8
str \rv, [\rp, #UART_LCR << UART_SHIFT]
b 100f

.align
99: .word .
.word tegra_uart_config
.ltorg

/* Load previously selected UART address */
100: ldr \rp, [\tmp, #4] @ Load tegra_uart_phys
ldr \rv, [\tmp, #8] @ Load tegra_uart_virt
.endm

#define UART_SHIFT 2

/*
* Code below is swiped from <asm/hardware/debug-8250.S>, but add an extra
* check to make sure that we aren't in the CONFIG_TEGRA_DEBUG_UART_NONE case.
* We use the fact that all 5 valid UART addresses all have something in the
* 2nd-to-lowest byte.
* check to make sure that the UART address is actually valid.
*/

.macro senduart, rd, rx
tst \rx, #0x0000ff00
cmp \rx, #0
strneb \rd, [\rx, #UART_TX << UART_SHIFT]
1001:
.endm

.macro busyuart, rd, rx
tst \rx, #0x0000ff00
cmp \rx, #0
beq 1002f
1001: ldrb \rd, [\rx, #UART_LSR << UART_SHIFT]
and \rd, \rd, #UART_LSR_TEMT | UART_LSR_THRE
Expand All @@ -90,7 +201,7 @@

.macro waituart, rd, rx
#ifdef FLOW_CONTROL
tst \rx, #0x0000ff00
cmp \rx, #0
beq 1002f
1001: ldrb \rd, [\rx, #UART_MSR << UART_SHIFT]
tst \rd, #UART_MSR_CTS
Expand Down
13 changes: 0 additions & 13 deletions arch/arm/mach-tegra/include/mach/uncompress.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,6 @@
#include <linux/serial_reg.h>

#include "../../iomap.h"
#include "../../irammap.h"

#define BIT(x) (1 << (x))
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
Expand All @@ -52,17 +51,6 @@ static inline void flush(void)
{
}

static inline void save_uart_address(void)
{
u32 *buf = (u32 *)(TEGRA_IRAM_BASE + TEGRA_IRAM_DEBUG_UART_OFFSET);

if (uart) {
buf[0] = TEGRA_IRAM_DEBUG_UART_COOKIE;
buf[1] = (u32)uart;
} else
buf[0] = 0;
}

static const struct {
u32 base;
u32 reset_reg;
Expand Down Expand Up @@ -169,7 +157,6 @@ static inline void arch_decomp_setup(void)
else
uart = (volatile u8 *)uarts[uart_id].base;

save_uart_address();
if (uart == NULL)
return;

Expand Down
9 changes: 0 additions & 9 deletions arch/arm/mach-tegra/irammap.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,13 +23,4 @@
#define TEGRA_IRAM_RESET_HANDLER_OFFSET 0
#define TEGRA_IRAM_RESET_HANDLER_SIZE SZ_1K

/*
* These locations are written to by uncompress.h, and read by debug-macro.S.
* The first word holds the cookie value if the data is valid. The second
* word holds the UART physical address.
*/
#define TEGRA_IRAM_DEBUG_UART_OFFSET SZ_1K
#define TEGRA_IRAM_DEBUG_UART_SIZE 8
#define TEGRA_IRAM_DEBUG_UART_COOKIE 0x55415254

#endif

0 comments on commit 1a6d3da

Please sign in to comment.