Santosh Shilimkar <santosh.shilimkar@xxxxxx> writes:
> On OMAP4 when attempting MPU off-mode or OSWR, the GIC context is
> lost. This patch adds GIC context save and restore support.
>
> The context save is done by software and restore is done by
> ROM code from predefined SAR locations where the context suppose
s/suppose/supposed/
> to be saved. Refer to ROM code specs for the GIC layout details.
Does this doc have a name? I've never seen such a thing and would
really like to.
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> Reviewed-by: Kevin Hilman <khilman@xxxxxx>
> ---
> arch/arm/mach-omap2/omap-hotplug.c | 4 +
> arch/arm/mach-omap2/omap4-mpuss-lowpower.c | 176 +++++++++++++++++++++++++++-
> arch/arm/mach-omap2/omap4-sar-layout.h | 20 +++
> 3 files changed, 199 insertions(+), 1 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap-hotplug.c b/arch/arm/mach-omap2/omap-hotplug.c
> index cf4ab15..deab389 100644
> --- a/arch/arm/mach-omap2/omap-hotplug.c
> +++ b/arch/arm/mach-omap2/omap-hotplug.c
> @@ -19,6 +19,8 @@
> #include <linux/smp.h>
>
> #include <asm/cacheflush.h>
> +#include <asm/hardware/gic.h>
> +
> #include <mach/omap4-common.h>
> #include <mach/omap-wakeupgen.h>
>
> @@ -58,6 +60,7 @@ void platform_cpu_die(unsigned int cpu)
> * clear all interrupt wakeup sources
> */
> omap_wakeupgen_irqmask_all(cpu, 1);
> + gic_secondary_set(0, true);
> omap4_enter_lowpower(cpu, PWRDM_POWER_OFF);
> this_cpu = hard_smp_processor_id();
> if (omap_read_auxcoreboot0() == this_cpu) {
> @@ -65,6 +68,7 @@ void platform_cpu_die(unsigned int cpu)
> * OK, proper wakeup, we're done
> */
> omap_wakeupgen_irqmask_all(this_cpu, 0);
> + gic_secondary_set(0, false);
>
> /* Restore clockdomain to hardware supervised */
> clkdm_allow_idle(cpu1_clkdm);
> diff --git a/arch/arm/mach-omap2/omap4-mpuss-lowpower.c b/arch/arm/mach-omap2/omap4-mpuss-lowpower.c
> index c0f358d..4140251 100644
> --- a/arch/arm/mach-omap2/omap4-mpuss-lowpower.c
> +++ b/arch/arm/mach-omap2/omap4-mpuss-lowpower.c
> @@ -47,6 +47,8 @@
> #include <asm/tlbflush.h>
> #include <asm/smp_scu.h>
> #include <asm/system.h>
> +#include <asm/irq.h>
> +#include <asm/hardware/gic.h>
>
> #include <plat/omap44xx.h>
> #include <mach/omap4-common.h>
> @@ -59,6 +61,19 @@
>
> #define CPU0_ID 0x0
> #define CPU1_ID 0x1
> +#define GIC_MASK_ALL 0x0
> +#define GIC_ISR_NON_SECURE 0xffffffff
> +#define SPI_ENABLE_SET_OFFSET 0x04
> +#define PPI_PRI_OFFSET 0x1c
> +#define SPI_PRI_OFFSET 0x20
> +#define SPI_TARGET_OFFSET 0x20
> +#define SPI_CONFIG_OFFSET 0x20
> +
> +/* GIC save SAR bank base */
> +static struct powerdomain *mpuss_pd;
> +
> +/* Variables to store maximum spi(Shared Peripheral Interrupts) registers. */
> +static u32 max_spi_irq, max_spi_reg;
>
> struct omap4_cpu_pm_info {
> struct powerdomain *pwrdm;
> @@ -67,6 +82,17 @@ struct omap4_cpu_pm_info {
>
> static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
>
> +/* Helper functions */
> +static inline void sar_writel(u32 val, u32 offset, u8 idx)
> +{
> + __raw_writel(val, sar_ram_base + offset + 4 * idx);
> +}
aha, this is what I was thinking of in the earlier SAR patch.
Something like this should be part of the SAR code, not here.
> +static inline u32 gic_readl(u32 offset, u8 idx)
> +{
> + return __raw_readl(gic_dist_base_addr + offset + 4 * idx);
> +}
Similarily, it would be nice tos see this as part of GIC code so
this code doesn't have to access a global base address pointer.
> /*
> * Set the CPUx powerdomain's previous power state
> */
> @@ -124,6 +150,85 @@ static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
> }
>
> /*
> + * Save GIC context in SAR RAM. Restore is done by ROM code
> + * GIC is lost only when MPU hits OSWR or OFF. It consists
> + * of a distributor and a per-CPU interface module. The GIC
> + * save restore is optimised to save only necessary registers.
> + */
> +static void gic_save_context(void)
> +{
> + u8 i;
> + u32 val;
> +
> + /*
> + * Interrupt Clear Enable registers are inverse of set enable
> + * and hence not needed to be saved. ROM code programs it
> + * based on Set Enable register values.
> + */
> +
> + /* Save CPU 0 Interrupt Set Enable register */
> + val = gic_readl(GIC_DIST_ENABLE_SET, 0);
> + sar_writel(val, ICDISER_CPU0_OFFSET, 0);
> +
> + /* Disable interrupts on CPU1 */
> + sar_writel(GIC_MASK_ALL, ICDISER_CPU1_OFFSET, 0);
> +
> + /* Save all SPI Set Enable register */
> + for (i = 0; i < max_spi_reg; i++) {
> + val = gic_readl(GIC_DIST_ENABLE_SET + SPI_ENABLE_SET_OFFSET, i);
> + sar_writel(val, ICDISER_SPI_OFFSET, i);
> + }
> +
> + /*
> + * Interrupt Priority Registers
> + * Secure sw accesses, last 5 bits of the 8 bits (bit[7:3] are used)
> + * Non-Secure sw accesses, last 4 bits (i.e. bits[7:4] are used)
> + * But the Secure Bits[7:3] are shifted by 1 in Non-Secure access.
> + * Secure (bits[7:3] << 1)== Non Secure bits[7:4]
> + * Hence right shift the value by 1 while saving the priority
> + */
> +
> + /* Save SGI priority registers (Software Generated Interrupt) */
> + for (i = 0; i < 4; i++) {
> + val = gic_readl(GIC_DIST_PRI, i);
> +
> + /* Save the priority bits of the Interrupts */
> + sar_writel(val >> 0x1, ICDIPR_SFI_CPU0_OFFSET, i);
> +
> + /* Disable the interrupts on CPU1 */
> + sar_writel(GIC_MASK_ALL, ICDIPR_SFI_CPU1_OFFSET, i);
> + }
> +
> + /* Save PPI priority registers (Private Peripheral Intterupts) */
> + val = gic_readl(GIC_DIST_PRI + PPI_PRI_OFFSET, 0);
> + sar_writel(val >> 0x1, ICDIPR_PPI_CPU0_OFFSET, 0);
> + sar_writel(GIC_MASK_ALL, ICDIPR_PPI_CPU1_OFFSET, 0);
> +
> + /* SPI priority registers - 4 interrupts/register */
> + for (i = 0; i < (max_spi_irq / 4); i++) {
> + val = gic_readl((GIC_DIST_PRI + SPI_PRI_OFFSET), i);
> + sar_writel(val >> 0x1, ICDIPR_SPI_OFFSET, i);
> + }
> +
> + /* SPI Interrupt Target registers - 4 interrupts/register */
> + for (i = 0; i < (max_spi_irq / 4); i++) {
> + val = gic_readl((GIC_DIST_TARGET + SPI_TARGET_OFFSET), i);
> + sar_writel(val, ICDIPTR_SPI_OFFSET, i);
> + }
> +
> + /* SPI Interrupt Congigeration eegisters- 16 interrupts/register */
> + for (i = 0; i < (max_spi_irq / 16); i++) {
> + val = gic_readl((GIC_DIST_CONFIG + SPI_CONFIG_OFFSET), i);
> + sar_writel(val, ICDICFR_OFFSET, i);
> + }
> +
> + /* Set the Backup Bit Mask status for GIC */
> + val = __raw_readl(sar_ram_base + SAR_BACKUP_STATUS_OFFSET);
> + val |= (SAR_BACKUP_STATUS_GIC_CPU0 | SAR_BACKUP_STATUS_GIC_CPU1);
> + __raw_writel(val, sar_ram_base + SAR_BACKUP_STATUS_OFFSET);
> +}
> +
> +/*
> * OMAP4 MPUSS Low Power Entry Function
> *
> * The purpose of this function is to manage low power programming
> @@ -131,11 +236,25 @@ static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
> * Paramenters:
> * cpu : CPU ID
> * power_state: Targetted Low power state.
> + *
> + * MPUSS Low power states
> + * The basic rule is that the MPUSS power domain must be at the higher or
> + * equal power state (state that consume more power) than the higher of the
> + * two CPUs. For example, it is illegal for system power to be OFF, while
> + * the power of one or both of the CPU is DORMANT. When an illegal state is
> + * entered, then the hardware behavior is unpredictable.
> + *
> + * MPUSS state for the context save
> + * save_state =
> + * 0 - Nothing lost and no need to save: MPUSS INACTIVE
> + * 1 - CPUx L1 and logic lost: MPUSS CSWR
> + * 2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
> + * 3 - CPUx L1 and logic lost + GIC + L2 lost: MPUSS OFF
> */
> int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
> {
> unsigned int save_state = 0;
> - unsigned int wakeup_cpu = hard_smp_processor_id();
> + unsigned int wakeup_cpu;
>
> if ((cpu > NR_CPUS) || (omap_rev() == OMAP4430_REV_ES1_0))
> goto ret;
> @@ -159,6 +278,23 @@ int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
> goto ret;
> }
>
> + /*
> + * MPUSS book keeping should be executed by master
> + * CPU only which is also the last CPU to go down.
> + */
> + if (cpu)
> + goto cpu_prepare;
> +
> + /*
> + * Check MPUSS next state and save GIC if needed
> + * GIC lost during MPU OFF and OSWR
> + */
> + if (pwrdm_read_next_pwrst(mpuss_pd) == PWRDM_POWER_OFF) {
> + gic_save_context();
> + save_state = 3;
> + }
> +
> +cpu_prepare:
> clear_cpu_prev_pwrst(cpu);
> set_cpu_next_pwrst(cpu, power_state);
> scu_pwrst_prepare(cpu, power_state);
> @@ -179,6 +315,19 @@ int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
> wakeup_cpu = hard_smp_processor_id();
> set_cpu_next_pwrst(wakeup_cpu, PWRDM_POWER_ON);
>
> + /* If !master cpu return to hotplug-path */
> + if (wakeup_cpu)
> + goto ret;
> +
> + /* Check MPUSS previous power state and enable GIC if needed */
> + if (pwrdm_read_prev_pwrst(mpuss_pd) == PWRDM_POWER_OFF) {
> + /* Clear SAR BACKUP status */
> + __raw_writel(0x0, sar_ram_base + SAR_BACKUP_STATUS_OFFSET);
> + /* Enable GIC distributor and inteface on CPU0*/
> + gic_secondary_set(CPU0_ID, 1);
> + gic_dist_set(CPU0_ID, 1);
> + }
> +
> ret:
> return 0;
> }
> @@ -189,6 +338,7 @@ ret:
> int __init omap4_mpuss_init(void)
> {
> struct omap4_cpu_pm_info *pm_info;
> + u8 i;
>
> if (omap_rev() == OMAP4430_REV_ES1_0) {
> WARN(1, "Power Management not supported on OMAP4430 ES1.0\n");
> @@ -234,6 +384,30 @@ int __init omap4_mpuss_init(void)
> __raw_writel(virt_to_phys(omap4_cpu_resume),
> sar_ram_base + CPU0_WAKEUP_NS_PA_ADDR_OFFSET);
>
> + mpuss_pd = pwrdm_lookup("mpu_pwrdm");
> + if (!mpuss_pd) {
> + pr_err("Failed to get lookup for MPUSS pwrdm\n");
> + return -ENODEV;
> + }
> +
> + /*
> + * Find out how many interrupts are supported.
> + * OMAP4 supports max of 128 SPIs where as GIC can support
> + * up to 1020 interrupt sources.
> + */
> + max_spi_reg = __raw_readl(gic_dist_base_addr + GIC_DIST_CTR) & 0x1f;
> + max_spi_irq = max_spi_reg * 32;
Based on the spec, this should also be max'd at 1020 so you never write
the reserved values after 1020.
Kevin
> + /*
> + * Mark the PPI and SPI interrupts as non-secure.
> + * program the SAR locations for interrupt security registers to
> + * reflect the same.
> + */
> + sar_writel(GIC_ISR_NON_SECURE, ICDISR_CPU0_OFFSET, 0);
> + sar_writel(GIC_ISR_NON_SECURE, ICDISR_CPU1_OFFSET, 0);
> + for (i = 0; i < max_spi_reg; i++)
> + sar_writel(GIC_ISR_NON_SECURE, ICDISR_SPI_OFFSET, i);
> +
> return 0;
> }
>
> diff --git a/arch/arm/mach-omap2/omap4-sar-layout.h b/arch/arm/mach-omap2/omap4-sar-layout.h
> index c4251db..0a19f49 100644
> --- a/arch/arm/mach-omap2/omap4-sar-layout.h
> +++ b/arch/arm/mach-omap2/omap4-sar-layout.h
> @@ -30,6 +30,26 @@
> #define CPU0_WAKEUP_NS_PA_ADDR_OFFSET 0xa04
> #define CPU1_WAKEUP_NS_PA_ADDR_OFFSET 0xa08
>
> + /* GIC save restore offset from SAR_BANK3 */
> +#define SAR_BACKUP_STATUS_OFFSET (SAR_BANK3_OFFSET + 0x500)
> +#define SAR_SECURE_RAM_SIZE_OFFSET (SAR_BANK3_OFFSET + 0x504)
> +#define SAR_SECRAM_SAVED_AT_OFFSET (SAR_BANK3_OFFSET + 0x508)
> +#define ICDISR_CPU0_OFFSET (SAR_BANK3_OFFSET + 0x50c)
> +#define ICDISR_CPU1_OFFSET (SAR_BANK3_OFFSET + 0x510)
> +#define ICDISR_SPI_OFFSET (SAR_BANK3_OFFSET + 0x514)
> +#define ICDISER_CPU0_OFFSET (SAR_BANK3_OFFSET + 0x524)
> +#define ICDISER_CPU1_OFFSET (SAR_BANK3_OFFSET + 0x528)
> +#define ICDISER_SPI_OFFSET (SAR_BANK3_OFFSET + 0x52c)
> +#define ICDIPR_SFI_CPU0_OFFSET (SAR_BANK3_OFFSET + 0x53c)
> +#define ICDIPR_PPI_CPU0_OFFSET (SAR_BANK3_OFFSET + 0x54c)
> +#define ICDIPR_SFI_CPU1_OFFSET (SAR_BANK3_OFFSET + 0x550)
> +#define ICDIPR_PPI_CPU1_OFFSET (SAR_BANK3_OFFSET + 0x560)
> +#define ICDIPR_SPI_OFFSET (SAR_BANK3_OFFSET + 0x564)
> +#define ICDIPTR_SPI_OFFSET (SAR_BANK3_OFFSET + 0x5e4)
> +#define ICDICFR_OFFSET (SAR_BANK3_OFFSET + 0x664)
> +#define SAR_BACKUP_STATUS_GIC_CPU0 0x1
> +#define SAR_BACKUP_STATUS_GIC_CPU1 0x2
> +
> #ifndef __ASSEMBLER__
>
> extern void __iomem *sar_ram_base;
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
