PPC440EP(x)/PPC440GR(x): In asynchronous PCI mode, the synchronous PCI clock must meet certain requirements. The following equation describes the relationship that must be maintained between the asynchronous PCI clock and synchronous PCI clock. Select an appropriate PCI:PLB ratio to maintain the relationship:
AsyncPCIClk - 1MHz <= SyncPCIclock <= (2 * AsyncPCIClk) - 1MHz
This patch now adds a function to check and reconfigure the sync PCI clock to meet this requirement. This is in preparation for some AMCC boards (Sequoia/Rainier and Yosemite/Yellowstone) using this function to not violate the PCI clocking rules.
Signed-off-by: Stefan Roese sr@denx.de --- cpu/ppc4xx/cpu_init.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++ include/ppc440.h | 7 ++++- include/ppc4xx.h | 2 + 3 files changed, 77 insertions(+), 1 deletions(-)
diff --git a/cpu/ppc4xx/cpu_init.c b/cpu/ppc4xx/cpu_init.c index a00da40..ccd9993 100644 --- a/cpu/ppc4xx/cpu_init.c +++ b/cpu/ppc4xx/cpu_init.c @@ -330,3 +330,72 @@ int cpu_init_r (void)
return 0; } + +#if defined(CONFIG_PCI) && \ + (defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \ + defined(CONFIG_440GR) || defined(CONFIG_440GRX)) +/* + * 440EP(x)/GR(x) PCI async/sync clocking restriction: + * + * In asynchronous PCI mode, the synchronous PCI clock must meet + * certain requirements. The following equation describes the + * relationship that must be maintained between the asynchronous PCI + * clock and synchronous PCI clock. Select an appropriate PCI:PLB + * ratio to maintain the relationship: + * + * AsyncPCIClk - 1MHz <= SyncPCIclock <= (2 * AsyncPCIClk) - 1MHz + */ +static int ppc4xx_pci_sync_clock_ok(u32 sync, u32 async) +{ + if (((async - 1000000) > sync) || (sync > ((2 * async) - 1000000))) + return 0; + else + return 1; +} + +int ppc4xx_pci_sync_clock_config(u32 async) +{ + sys_info_t sys_info; + u32 sync; + int div; + u32 reg; + u32 spcid_val[] = { + CPR0_SPCID_SPCIDV0_DIV1, CPR0_SPCID_SPCIDV0_DIV2, + CPR0_SPCID_SPCIDV0_DIV3, CPR0_SPCID_SPCIDV0_DIV4 }; + + get_sys_info(&sys_info); + sync = sys_info.freqPCI; + + /* + * First check if the equation above is met + */ + if (!ppc4xx_pci_sync_clock_ok(sync, async)) { + /* + * Reconfigure PCI sync clock to meet the equation. + * Start with highest possible PCI sync frequency + * (divider 1). + */ + for (div = 1; div <= 4; div++) { + sync = sys_info.freqPLB / div; + if (ppc4xx_pci_sync_clock_ok(sync, async)) + break; + } + + if (div <= 4) { + mtcpr(CPR0_SPCID, spcid_val[div]); + + mfcpr(CPR0_ICFG, reg); + reg |= CPR0_ICFG_RLI_MASK; + mtcpr(CPR0_ICFG, reg); + + /* do chip reset */ + mtspr(SPRN_DBCR0, 0x20000000); + } else { + /* Impossible to configure the PCI sync clock */ + return -1; + } + } + + return 0; +} +#endif diff --git a/include/ppc440.h b/include/ppc440.h index fe0db93..e54a977 100644 --- a/include/ppc440.h +++ b/include/ppc440.h @@ -1701,9 +1701,14 @@ #define PLLSYS1_NTO1_MASK 0x00000001 /* CPU:PLB N-to-1 ratio */ #endif /* CONFIG_440GX */
-#if defined (CONFIG_440EPX) || defined (CONFIG_440GRX) +#if defined(CONFIG_440EP) || defined(CONFIG_440GR) || \ + defined(CONFIG_440EPX) || defined(CONFIG_440GRX) #define CPR0_ICFG_RLI_MASK 0x80000000 #define CPR0_SPCID_SPCIDV0_MASK 0x03000000 +#define CPR0_SPCID_SPCIDV0_DIV1 0x01000000 +#define CPR0_SPCID_SPCIDV0_DIV2 0x02000000 +#define CPR0_SPCID_SPCIDV0_DIV3 0x03000000 +#define CPR0_SPCID_SPCIDV0_DIV4 0x00000000 #define CPR0_PERD_PERDV0_MASK 0x07000000 #endif
diff --git a/include/ppc4xx.h b/include/ppc4xx.h index 3bff00a..5024db4 100644 --- a/include/ppc4xx.h +++ b/include/ppc4xx.h @@ -221,6 +221,8 @@ static inline void set_mcsr(u32 val) asm volatile("mtspr 0x23c, %0" : "=r" (val) :); }
+int ppc4xx_pci_sync_clock_config(u32 async); + #endif /* __ASSEMBLY__ */
/* for multi-cpu support */