[PATCH 13/26] x86: apl: Adjust how the UART gets its platform data

Simon Glass
2020-12-19T17:40:05Z

At present this driver calls malloc() to start a new platform data
structure, fills it in and tells driver model to use it.

We want to avoid malloc, particularly with the new version of of-platdata.
Create a new struct which encompasses both the dtd struct and the ns16550
one, to avoid this. Unfortunately we must copy the data into the right
place for the ns16550 driver. Add some comments about this.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

arch/x86/cpu/apollolake/uart.c | 43 ++++++++++++---------
arch/x86/include/asm/arch-apollolake/uart.h | 19 ++++++++-
2 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/arch/x86/cpu/apollolake/uart.c b/arch/x86/cpu/apollolake/uart.c
index 69e5899235b..876fa592b8d 100644
--- a/arch/x86/cpu/apollolake/uart.c
+++ b/arch/x86/cpu/apollolake/uart.c
@@ -17,6 +17,7 @@
#include <asm/pci.h>
#include <asm/lpss.h>
#include <dm/device-internal.h>
+#include <asm/arch/uart.h>

/* Low-power Subsystem (LPSS) clock register */
enum {
@@ -69,7 +70,7 @@ void apl_uart_init(pci_dev_t bdf, ulong base)
* This driver uses its own compatible string but almost everything else from
* the standard ns16550 driver. This allows us to provide an of-platdata
* implementation, since the platdata produced by of-platdata does not match
- * struct ns16550_plat.
+ * struct apl_ns16550_plat.
*
* When running with of-platdata (generally TPL), the platdata is converted to
* something that ns16550 expects. When running withoutof-platdata (SPL, U-Boot
@@ -78,10 +79,10 @@ void apl_uart_init(pci_dev_t bdf, ulong base)

static int apl_ns16550_probe(struct udevice *dev)
{
- struct ns16550_plat *plat = dev_get_plat(dev);
+ struct apl_ns16550_plat *plat = dev_get_plat(dev);

if (!CONFIG_IS_ENABLED(PCI))
- apl_uart_init(plat->bdf, plat->base);
+ apl_uart_init(plat->ns16550.bdf, plat->ns16550.base);

return ns16550_serial_probe(dev);
}
@@ -89,24 +90,28 @@ static int apl_ns16550_probe(struct udevice *dev)
static int apl_ns16550_of_to_plat(struct udevice *dev)
{
#if CONFIG_IS_ENABLED(OF_PLATDATA)
- struct dtd_intel_apl_ns16550 *dtplat = dev_get_plat(dev);
- struct ns16550_plat *plat;
+ struct dtd_intel_apl_ns16550 *dtplat;
+ struct apl_ns16550_plat *plat = dev_get_plat(dev);
+ struct ns16550_plat ns;

/*
- * Convert our plat to the ns16550's plat, so we can just use
- * that driver
+ * The device's plat uses struct apl_ns16550_plat which starts with the
+ * dtd struct, but the ns16550 driver expects it to be struct ns16550.
+ * Set up what that driver expects. Note that this means that the values
+ * cannot be read in this driver when using of-platdata.
+ *
+ * TODO(sjg at chromium.org): Consider having a separate plat pointer for
+ * of-platdata so that it is not necessary to overwrite this.
*/
- plat = malloc(sizeof(*plat));
- if (!plat)
- return -ENOMEM;
- plat->base = dtplat->early_regs[0];
- plat->reg_width = 1;
- plat->reg_shift = dtplat->reg_shift;
- plat->reg_offset = 0;
- plat->clock = dtplat->clock_frequency;
- plat->fcr = UART_FCR_DEFVAL;
- plat->bdf = pci_ofplat_get_devfn(dtplat->reg[0]);
- dev_set_plat(dev, plat);
+ dtplat = &plat->dtplat;
+ ns.base = dtplat->early_regs[0];
+ ns.reg_width = 1;
+ ns.reg_shift = dtplat->reg_shift;
+ ns.reg_offset = 0;
+ ns.clock = dtplat->clock_frequency;
+ ns.fcr = UART_FCR_DEFVAL;
+ ns.bdf = pci_ofplat_get_devfn(dtplat->reg[0]);
+ memcpy(plat, &ns, sizeof(ns));
#else
int ret;

@@ -129,7 +134,7 @@ U_BOOT_DRIVER(intel_apl_ns16550) = {
.name = "intel_apl_ns16550",
.id = UCLASS_SERIAL,
.of_match = of_match_ptr(apl_ns16550_serial_ids),
- .plat_auto = sizeof(struct ns16550_plat),
+ .plat_auto = sizeof(struct apl_ns16550_plat),
.priv_auto = sizeof(struct ns16550),
.ops = &ns16550_serial_ops,
.of_to_plat = apl_ns16550_of_to_plat,
diff --git a/arch/x86/include/asm/arch-apollolake/uart.h b/arch/x86/include/asm/arch-apollolake/uart.h
index d4fffe6525c..38335b04903 100644
--- a/arch/x86/include/asm/arch-apollolake/uart.h
+++ b/arch/x86/include/asm/arch-apollolake/uart.h
@@ -6,6 +6,23 @@
#ifndef _ASM_ARCH_UART_H
#define _ASM_ARCH_UART_H

+#include <ns16550.h>
+
+/**
+ * struct apl_ns16550_plat - platform data for the APL UART
+ *
+ * Note that when of-platdata is in use, apl_ns16550_of_to_plat() actually
+ * copies the ns16550_plat contents to the start of this struct, meaning that
+ * dtplat is no-longer valid. This is done so that the ns16550 driver can use
+ * dev_get_plat() without any offsets or adjustments.
+ */
+struct apl_ns16550_plat {
+#if CONFIG_IS_ENABLED(OF_PLATDATA)
+ struct dtd_intel_apl_ns16550 dtplat;
+#endif
+ struct ns16550_plat ns16550;
+};
+
/**
* apl_uart_init() - Set up the APL UART device and clock
*
@@ -15,6 +32,6 @@
* The UART won't actually work unless the GPIO settings are correct and the
* signals actually exit the SoC. See board_debug_uart_init() for that.
*/
-int apl_uart_init(pci_dev_t bdf, ulong base);
+void apl_uart_init(pci_dev_t bdf, ulong base);

#endif
--
2.29.2.684.gfbc64c5ab5-goog