drivers/intel/fsp2_0: Add options to config VGA mode 12

This commit adds new Kconfig options and a code snippet to support
VGA mode 12 within the FSP (Firmware Support Package) 2.0. The
changes allow platforms to select VGA mode 12 and configure it.

The key features are:
- Introduces `FSP_VGA_MODE12` to enable VGA mode 12 support.
- A new `FSP_VGA_MODE12_BPP` option defines the bits per pixel,
  defaulting to 4 for color mode.
- A bitmap buffer is allocated on the stack and supplied to FSP
  based on the configured bits per pixel.

BUG=b:406725440
TEST=Verify VGA text rotation on Google/Felino.

Change-Id: Iaa3a64b7c8c735d8329b3596f4be315871bc7fa4
Signed-off-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/89090
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>

src/drivers/intel/fsp2_0/Kconfig

@@ -500,4 +500,19 @@ config FSP_DIMM_INFO
 	  Select this option to retrieve DIMM (Memory) related information by relying on
 	  the Intel FSP. coreboot relies on this information to prepare SMBIOS table 17.
 
+config FSP_VGA_MODE12
+	bool
+	default n
+	depends on VGA || ROMSTAGE_VGA
+	help
+	  Select this if the FSP supports VGA mode 12.
+
+config FSP_VGA_MODE12_BPP
+	hex
+	default 0x4 if FSP_VGA_MODE12
+	default 0x0
+	help
+	  This is the number of bits per pixel used by FSP in VGA mode 12.
+	  A bitmap buffer is allocated based on this value and supplied to FSP.
+
 endif

src/drivers/intel/fsp2_0/include/fsp/api.h

@@ -129,6 +129,12 @@ static inline void soc_load_logo_by_coreboot(void) { /* nop */ }
 static inline int soc_mark_gfx_memory(void) { return -1; }
 #endif
 
+#if CONFIG(FSP_VGA_MODE12)
+void soc_set_vga_mode12_buffer(FSPM_UPD *fspm_upd, uintptr_t buffer);
+#else
+static inline void soc_set_vga_mode12_buffer(FSPM_UPD *fspm_upd, uintptr_t buffer) { /* nop */ }
+#endif
+
 /* Update the SOC specific memory config param for mma. */
 void soc_update_memory_params_for_mma(FSP_M_CONFIG *memory_cfg,
 	struct mma_config_param *mma_cfg);

src/drivers/intel/fsp2_0/memory_init.c

@@ -405,6 +405,16 @@ static void do_fsp_memory_init(const struct fspm_context *context, bool s3wake)
 	/* Reserve enough memory under TOLUD to save CBMEM header */
 	arch_upd->BootLoaderTolumSize = cbmem_overhead_size();
 
+#if CONFIG_FSP_VGA_MODE12_BPP
+	/* Allocate a buffer for VGA mode 12 on the stack since we do not have
+	 * memory available yet. It is done here to avoid deallocation before
+	 * calling FSP-M.
+	 */
+	unsigned char temp_vga_buffer[CONFIG_FSP_VGA_MODE12_BPP * VGA12_BITMAP_BUFFER_SZ];
+	memset(temp_vga_buffer, 0, sizeof(temp_vga_buffer));
+	soc_set_vga_mode12_buffer(&fspm_upd, (uintptr_t)temp_vga_buffer);
+#endif
+
 	/* Fill common settings on behalf of chipset. */
 	if (fsp_fill_common_arch_params(arch_upd, s3wake, version,
 					memmap) != CB_SUCCESS)